#65304 - Add commons-io as a dependency

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1889871 13f79535-47bb-0310-9956-ffa450edef68

288 files changed, 8170 insertions, 9147 deletions

diff --git a/build.gradle b/build.gradle
index 2ee40a3092..debb97b3bf 100644
--- a/build.gradle
+++ b/build.gradle
@@ -100,6 +100,7 @@ subprojects {
         bouncyCastleVersion = '1.68'
         commonsCodecVersion = '1.15'
         commonsCompressVersion = '1.20'
+        commonsIoVersion = '2.8.0'
         commonsMathVersion = '3.6.1'
         junitVersion = '5.7.1'
         log4jVersion = '2.14.0'
@@ -117,6 +118,8 @@ subprojects {
 
     tasks.withType(JavaCompile) {
         options.encoding = 'UTF-8'
+        options.compilerArgs << '-Xlint:unchecked'
+        options.deprecation = true
     }
 
     tasks.withType(Jar) {
@@ -371,6 +374,7 @@ rat {
     excludes.add("**/out/**")
     excludes.add("**/*.iml")
     excludes.add("**/*.log")
+    excludes.add("**/gradle-wrapper.properties")
     excludes.add("**/main/java/org/apache/poi/**/*-chart-data.txt")
     excludes.add("poi/src/main/resources/org/apache/poi/sl/draw/geom/presetShapeDefinitions.xml")
     excludes.add("poi-ooxml/src/main/resources/org/apache/poi/xslf/usermodel/notesMaster.xml")
diff --git a/build.xml b/build.xml
index afe0ef2663..f5557a5470 100644
--- a/build.xml
+++ b/build.xml
@@ -266,6 +266,7 @@ under the License.
     <dependency prefix="main.commons-codec" artifact="commons-codec:commons-codec:1.15" usage="main"/>
     <dependency prefix="main.commons-collections4" artifact="org.apache.commons:commons-collections4:4.4" usage="main"/>
     <dependency prefix="main.commons-math3" artifact="org.apache.commons:commons-math3:3.6.1" usage="main"/>
+    <dependency prefix="main.commons-io" artifact="commons-io:commons-io:2.8.0" usage="main"/>
     <dependency prefix="main.com.zaxxer" artifact="com.zaxxer:SparseBitSet:1.2" usage="main"/>
     <dependency prefix="main.log4j-api" artifact="org.apache.logging.log4j:log4j-api:2.14.0" usage="main"/>
 
@@ -430,6 +431,7 @@ under the License.
         <pathelement location="${main.commons-codec.jar}"/>
         <pathelement location="${main.commons-collections4.jar}"/>
         <pathelement location="${main.commons-math3.jar}"/>
+        <pathelement location="${main.commons-io.jar}"/>
         <pathelement location="${main.com.zaxxer.jar}"/>
         <pathelement location="${main.log4j-api.jar}"/>
     </path>
@@ -737,6 +739,7 @@ under the License.
                     <available file="${dsig.xmlsec.jar}"/>
                     <available file="${main.commons-collections4.jar}"/>
                     <available file="${main.commons-math3.jar}"/>
+                    <available file="${main.commons-io.jar}"/>
                     <available file="${main.com.zaxxer.jar}"/>
 
                     <!-- we had some CI failures when the extracted files for JaCoCo were missing somehow... -->
@@ -778,6 +781,7 @@ under the License.
         <downloadfile src="${jacoco.url}" dest="${jacoco.zip}"/>
         <downloadfile src="${main.commons-collections4.url}" dest="${main.commons-collections4.jar}"/>
         <downloadfile src="${main.commons-math3.url}" dest="${main.commons-math3.jar}"/>
+        <downloadfile src="${main.commons-io.url}" dest="${main.commons-io.jar}"/>
         <downloadfile src="${main.com.zaxxer.url}" dest="${main.com.zaxxer.jar}"/>
         <unzip src="${jacoco.zip}" dest="${util.lib}">
             <patternset>
@@ -2328,6 +2332,7 @@ under the License.
                     <include name="commons-codec-*.jar"/>
                     <include name="commons-collections4-*.jar"/>
                     <include name="commons-math3-*.jar"/>
+                    <include name="commons-io-*.jar"/>
                     <include name="log4j-api-*.jar"/>
                     <include name="SparseBitSet-*.jar"/>
                 </fileset>
@@ -2687,6 +2692,7 @@ under the License.
             <auxClasspath path="${ooxml.commons-compress.jar}" />
             <auxClasspath path="${main.commons-collections4.jar}" />
             <auxClasspath path="${main.commons-math3.jar}" />
+            <auxClasspath path="${main.commons-io.jar}" />
             <auxClasspath path="${main.commons-codec.jar}" />
             <auxClasspath path="${main.commons-logging.jar}" />
             <auxClasspath path="${main.log4j-api.jar}" />
diff --git a/maven/poi.pom b/maven/poi.pom
index 743a3f3d79..13d7344021 100644
--- a/maven/poi.pom
+++ b/maven/poi.pom
@@ -77,6 +77,11 @@
             <version>3.6.1</version>
         </dependency>
         <dependency>
+            <groupId>commons-io</groupId>
+            <artifactId>commons-io</artifactId>
+            <version>2.8.0</version>
+        </dependency>
+        <dependency>
             <groupId>com.zaxxer</groupId>
             <artifactId>SparseBitSet</artifactId>
             <version>1.2</version>
diff --git a/osgi/README.md b/osgi/README.md
index 01bbc68f49..f241dc973b 100644
--- a/osgi/README.md
+++ b/osgi/README.md
@@ -9,6 +9,7 @@ The bundle embeds all the jars from lib/main:
 - SparseBitSet
 - curvesapi
 - commons-math3
+- commons-io
 - commons-compress
 - commons-collections4
 - commons-codec
diff --git a/osgi/pom.xml b/osgi/pom.xml
index 97afc8b4bb..b16e9f9302 100644
--- a/osgi/pom.xml
+++ b/osgi/pom.xml
@@ -101,6 +101,7 @@
                             SparseBitSet,
                             curvesapi,
                             commons-math3,
+                            commons-io,
                             commons-compress,
                             commons-collections4,
                             commons-codec,
diff --git a/osgi/src/test/java/org/apache/poi/osgi/OSGiExtractorsIT.java b/osgi/src/test/java/org/apache/poi/osgi/OSGiExtractorsIT.java
index 8ee1258fa4..3bf58a2b61 100755
--- a/osgi/src/test/java/org/apache/poi/osgi/OSGiExtractorsIT.java
+++ b/osgi/src/test/java/org/apache/poi/osgi/OSGiExtractorsIT.java
@@ -36,7 +36,7 @@ import org.ops4j.pax.exam.spi.reactors.PerClass;
 
 import java.awt.*;
 import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 
 import static org.junit.Assert.assertEquals;
 
@@ -57,7 +57,7 @@ public class OSGiExtractorsIT extends BaseOSGiTestCase {
         box.setText("Hello, World!");
         box.setAnchor(new Rectangle(36, 15, 648, 65));
 
-        ByteArrayOutputStream out = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream out = new UnsynchronizedByteArrayOutputStream();
         ppt.write(out);
         return out.toByteArray();
     }
@@ -66,7 +66,7 @@ public class OSGiExtractorsIT extends BaseOSGiTestCase {
         Sheet s = wb.createSheet("OSGi");
         s.createRow(0).createCell(0).setCellValue("Hello, World!");
 
-        ByteArrayOutputStream out = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream out = new UnsynchronizedByteArrayOutputStream();
         wb.write(out);
         return out.toByteArray();
 
diff --git a/osgi/src/test/java/org/apache/poi/osgi/OSGiSlideShowIT.java b/osgi/src/test/java/org/apache/poi/osgi/OSGiSlideShowIT.java
index ef18f1cc95..9744c36ca9 100755
--- a/osgi/src/test/java/org/apache/poi/osgi/OSGiSlideShowIT.java
+++ b/osgi/src/test/java/org/apache/poi/osgi/OSGiSlideShowIT.java
@@ -28,7 +28,7 @@ import org.ops4j.pax.exam.spi.reactors.PerClass;
 
 import java.awt.*;
 import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import java.util.List;
 
 import static org.junit.Assert.assertEquals;
@@ -75,11 +75,12 @@ public class OSGiSlideShowIT extends BaseOSGiTestCase {
         }
         box2.setAnchor(new Rectangle(36, 80, 648, 400));
 
-        ByteArrayOutputStream baos = new ByteArrayOutputStream();
-        ppt.write(baos);
-        ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
-
-        ppt = SlideShowFactory.create(bais);
+        try (UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream()) {
+            ppt.write(baos);
+            try (InputStream bais = baos.toInputStream()) {
+                ppt = SlideShowFactory.create(bais);
+            }
+        }
         assertEquals(1, ppt.getSlides().size());
         slide = (Slide) ppt.getSlides().iterator().next();
         assertEquals(2, slide.getShapes().size());
diff --git a/osgi/src/test/java/org/apache/poi/osgi/OSGiSpreadsheetIT.java b/osgi/src/test/java/org/apache/poi/osgi/OSGiSpreadsheetIT.java
index 0ea95602c9..618b76e36c 100644
--- a/osgi/src/test/java/org/apache/poi/osgi/OSGiSpreadsheetIT.java
+++ b/osgi/src/test/java/org/apache/poi/osgi/OSGiSpreadsheetIT.java
@@ -29,7 +29,7 @@ import org.ops4j.pax.exam.spi.reactors.ExamReactorStrategy;
 import org.ops4j.pax.exam.spi.reactors.PerClass;
 
 import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 
 import static org.junit.Assert.assertEquals;
 
@@ -48,11 +48,12 @@ public class OSGiSpreadsheetIT extends BaseOSGiTestCase {
         s.createRow(0).createCell(0).setCellValue("With OSGi");
         s.createRow(1).createCell(0).setCellFormula("SUM(A1:B3)");
 
-        ByteArrayOutputStream baos = new ByteArrayOutputStream();
-        wb.write(baos);
-        ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
-
-        wb = WorkbookFactory.create(bais);
+        try (UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream()) {
+            wb.write(baos);
+            try (InputStream bais = baos.toInputStream()) {
+                wb = WorkbookFactory.create(bais);
+            }
+        }
         assertEquals(1, wb.getNumberOfSheets());
 
         s = wb.getSheet("OSGi");
diff --git a/poi-examples/src/main/java/org/apache/poi/examples/hpsf/WriteAuthorAndTitle.java b/poi-examples/src/main/java/org/apache/poi/examples/hpsf/WriteAuthorAndTitle.java
index 94ceaf6c03..71f4d8aa93 100644
--- a/poi-examples/src/main/java/org/apache/poi/examples/hpsf/WriteAuthorAndTitle.java
+++ b/poi-examples/src/main/java/org/apache/poi/examples/hpsf/WriteAuthorAndTitle.java
@@ -24,7 +24,6 @@ import java.io.InputStream;
 import java.io.OutputStream;
 
 import org.apache.poi.hpsf.HPSFRuntimeException;
-import org.apache.poi.hpsf.MarkUnsupportedException;
 import org.apache.poi.hpsf.NoPropertySetStreamException;
 import org.apache.poi.hpsf.PropertySet;
 import org.apache.poi.hpsf.PropertySetFactory;
@@ -165,7 +164,7 @@ public final class WriteAuthorAndTitle {
                 de.createDocument(event.getName(), is);
             }
 
-        } catch (MarkUnsupportedException | WritingNotSupportedException | IOException | NoPropertySetStreamException ex) {
+        } catch (WritingNotSupportedException | IOException | NoPropertySetStreamException ex) {
             // According to the definition of the processPOIFSReaderEvent method we cannot pass checked
             // exceptions to the caller.
             throw new HPSFRuntimeException("Could not read file " + event.getPath() + "/" + event.getName(), ex);
diff --git a/poi-examples/src/main/java/org/apache/poi/examples/hssf/usermodel/OfficeDrawing.java b/poi-examples/src/main/java/org/apache/poi/examples/hssf/usermodel/OfficeDrawing.java
index 4603864d86..2cefd3d87f 100644
--- a/poi-examples/src/main/java/org/apache/poi/examples/hssf/usermodel/OfficeDrawing.java
+++ b/poi-examples/src/main/java/org/apache/poi/examples/hssf/usermodel/OfficeDrawing.java
@@ -17,11 +17,12 @@
 
 package org.apache.poi.examples.hssf.usermodel;
 
-import java.io.ByteArrayOutputStream;
 import java.io.FileInputStream;
 import java.io.FileOutputStream;
 import java.io.IOException;
 
+import org.apache.commons.io.IOUtils;
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.hssf.usermodel.HSSFChildAnchor;
 import org.apache.poi.hssf.usermodel.HSSFClientAnchor;
 import org.apache.poi.hssf.usermodel.HSSFFont;
@@ -188,14 +189,11 @@ public final class OfficeDrawing {
 
     }
 
-    private static int loadPicture( String path, HSSFWorkbook wb ) throws IOException
-    {
+    private static int loadPicture( String path, HSSFWorkbook wb ) throws IOException {
         int pictureIndex;
         try (FileInputStream fis = new FileInputStream(path);
-             ByteArrayOutputStream bos = new ByteArrayOutputStream()) {
-            int c;
-            while ((c = fis.read()) != -1)
-                bos.write(c);
+             UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream()) {
+            IOUtils.copy(fis, bos);
             pictureIndex = wb.addPicture(bos.toByteArray(), Workbook.PICTURE_TYPE_PNG);
         }
         return pictureIndex;
diff --git a/poi-examples/src/main/java/org/apache/poi/examples/xssf/usermodel/CustomXMLMapping.java b/poi-examples/src/main/java/org/apache/poi/examples/xssf/usermodel/CustomXMLMapping.java
index ebc04a4d33..edba46bba3 100644
--- a/poi-examples/src/main/java/org/apache/poi/examples/xssf/usermodel/CustomXMLMapping.java
+++ b/poi-examples/src/main/java/org/apache/poi/examples/xssf/usermodel/CustomXMLMapping.java
@@ -16,8 +16,9 @@
 ==================================================================== */
 package org.apache.poi.examples.xssf.usermodel;
 
-import java.io.ByteArrayOutputStream;
+import java.nio.charset.StandardCharsets;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.openxml4j.opc.OPCPackage;
 import org.apache.poi.xssf.extractor.XSSFExportToXml;
 import org.apache.poi.xssf.usermodel.XSSFMap;
@@ -37,9 +38,9 @@ public final class CustomXMLMapping {
             for (XSSFMap map : wb.getCustomXMLMappings()) {
                 XSSFExportToXml exporter = new XSSFExportToXml(map);
 
-                ByteArrayOutputStream os = new ByteArrayOutputStream();
+                UnsynchronizedByteArrayOutputStream os = new UnsynchronizedByteArrayOutputStream();
                 exporter.exportToXML(os, true);
-                String xml = os.toString("UTF-8");
+                String xml = os.toString(StandardCharsets.UTF_8);
                 System.out.println(xml);
             }
         }
diff --git a/poi-examples/src/test/java/org/apache/poi/integration/TestXLSX2CSV.java b/poi-examples/src/test/java/org/apache/poi/integration/TestXLSX2CSV.java
index 6863fc9bbe..f21f512284 100644
--- a/poi-examples/src/test/java/org/apache/poi/integration/TestXLSX2CSV.java
+++ b/poi-examples/src/test/java/org/apache/poi/integration/TestXLSX2CSV.java
@@ -20,9 +20,10 @@ package org.apache.poi.integration;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import java.io.ByteArrayOutputStream;
 import java.io.PrintStream;
+import java.nio.charset.StandardCharsets;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.examples.xssf.eventusermodel.XLSX2CSV;
 import org.apache.poi.openxml4j.opc.OPCPackage;
 import org.apache.poi.openxml4j.opc.PackageAccess;
@@ -33,7 +34,7 @@ import org.junit.jupiter.api.Test;
 
 public class TestXLSX2CSV {
 	private PrintStream err;
-	private final ByteArrayOutputStream errorBytes = new ByteArrayOutputStream();
+	private final UnsynchronizedByteArrayOutputStream errorBytes = new UnsynchronizedByteArrayOutputStream();
 
 	@BeforeEach
 	public void setUp() {
@@ -45,13 +46,13 @@ public class TestXLSX2CSV {
 	}
 
 	@AfterEach
-	public void tearDown() throws Exception {
+	public void tearDown() {
 		// restore output-streams again
 		System.setErr(err);
 
 		// Print out found error
 		if (errorBytes.size() > 0) {
-			System.err.println("Had stderr: " + errorBytes.toString("UTF-8"));
+			System.err.println("Had stderr: " + errorBytes.toString(StandardCharsets.UTF_8));
 		}
 	}
 
@@ -60,7 +61,7 @@ public class TestXLSX2CSV {
 		// returns with some System.err
 		XLSX2CSV.main(new String[0]);
 
-		String output = errorBytes.toString("UTF-8");
+		String output = errorBytes.toString(StandardCharsets.UTF_8);
 		assertTrue(output.contains("XLSX2CSV <xlsx file>"), "Had: " + output);
 	}
 
@@ -75,7 +76,7 @@ public class TestXLSX2CSV {
 
 	@Test
 	public void testSampleFile() throws Exception {
-		final ByteArrayOutputStream outputBytes = new ByteArrayOutputStream();
+		final UnsynchronizedByteArrayOutputStream outputBytes = new UnsynchronizedByteArrayOutputStream();
 		PrintStream out = new PrintStream(outputBytes);
 
 		// The package open is instantaneous, as it should be.
@@ -84,17 +85,17 @@ public class TestXLSX2CSV {
 			xlsx2csv.process();
 		}
 
-		String errorOutput = errorBytes.toString("UTF-8");
+		String errorOutput = errorBytes.toString(StandardCharsets.UTF_8);
 		assertEquals(errorOutput.length(), 0);
 
-		String output = outputBytes.toString("UTF-8");
+		String output = outputBytes.toString(StandardCharsets.UTF_8);
 		assertTrue(output.contains("\"Lorem\",111"), "Had: " + output);
 		assertTrue(output.contains(",\"hello, xssf\",,\"hello, xssf\""), "Had: " + output);
 	}
 
 	@Test
 	public void testMinColumns() throws Exception {
-		final ByteArrayOutputStream outputBytes = new ByteArrayOutputStream();
+		final UnsynchronizedByteArrayOutputStream outputBytes = new UnsynchronizedByteArrayOutputStream();
 		PrintStream out = new PrintStream(outputBytes);
 
 		// The package open is instantaneous, as it should be.
@@ -103,10 +104,10 @@ public class TestXLSX2CSV {
 			xlsx2csv.process();
 		}
 
-		String errorOutput = errorBytes.toString("UTF-8");
+		String errorOutput = errorBytes.toString(StandardCharsets.UTF_8);
 		assertEquals(errorOutput.length(), 0);
 
-		String output = outputBytes.toString("UTF-8");
+		String output = outputBytes.toString(StandardCharsets.UTF_8);
 		assertTrue(output.contains("\"Lorem\",111,,,"), "Had: " + output);
 		assertTrue(output.contains(",\"hello, xssf\",,\"hello, xssf\","), "Had: " + output);
 	}
diff --git a/poi-excelant/src/test/java/org/apache/poi/ss/excelant/TestBuildFile.java b/poi-excelant/src/test/java/org/apache/poi/ss/excelant/TestBuildFile.java
index 2a2b36b827..df3509cd74 100644
--- a/poi-excelant/src/test/java/org/apache/poi/ss/excelant/TestBuildFile.java
+++ b/poi-excelant/src/test/java/org/apache/poi/ss/excelant/TestBuildFile.java
@@ -28,7 +28,7 @@ import java.io.File;
 import java.io.PrintStream;
 
 import org.apache.poi.POIDataSamples;
-import org.apache.poi.util.NullPrintStream;
+import org.apache.commons.io.output.NullPrintStream;
 import org.apache.tools.ant.BuildEvent;
 import org.apache.tools.ant.BuildListener;
 import org.apache.tools.ant.Project;
diff --git a/poi-integration/src/test/java/org/apache/poi/stress/HPSFFileHandler.java b/poi-integration/src/test/java/org/apache/poi/stress/HPSFFileHandler.java
index 088f77ef45..53ca398b5c 100644
--- a/poi-integration/src/test/java/org/apache/poi/stress/HPSFFileHandler.java
+++ b/poi-integration/src/test/java/org/apache/poi/stress/HPSFFileHandler.java
@@ -21,7 +21,6 @@ import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.fail;
 import static org.junit.jupiter.api.Assumptions.assumeFalse;
 
-import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.IOException;
@@ -33,6 +32,7 @@ import java.util.Collections;
 import java.util.HashSet;
 import java.util.Set;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.examples.hpsf.CopyCompare;
 import org.apache.poi.hpsf.DocumentSummaryInformation;
 import org.apache.poi.hpsf.HPSFPropertiesOnlyDocument;
@@ -104,11 +104,11 @@ class HPSFFileHandler extends POIFSFileHandler {
     public void handleAdditional(File file) throws Exception {
         assumeFalse(EXCLUDES_HANDLE_ADD.contains(file.getParentFile().getName()+"/"+file.getName()));
 
-        ByteArrayOutputStream bos = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream();
         PrintStream psNew = new PrintStream(bos, true, "ISO-8859-1");
         CopyCompare.setOut(psNew);
         CopyCompare.main(new String[]{file.getAbsolutePath(), copyOutput.get().getAbsolutePath()});
-        assertEquals("Equal" + NL, bos.toString(StandardCharsets.UTF_8.name()));
+        assertEquals("Equal" + NL, bos.toString(StandardCharsets.UTF_8));
     }
 
 
diff --git a/poi-integration/src/test/java/org/apache/poi/stress/HSSFFileHandler.java b/poi-integration/src/test/java/org/apache/poi/stress/HSSFFileHandler.java
index 1e0348cac5..f8e0de4ff1 100644
--- a/poi-integration/src/test/java/org/apache/poi/stress/HSSFFileHandler.java
+++ b/poi-integration/src/test/java/org/apache/poi/stress/HSSFFileHandler.java
@@ -33,7 +33,7 @@ import org.apache.poi.hssf.usermodel.HSSFWorkbook;
 import org.apache.poi.ss.usermodel.Cell;
 import org.apache.poi.ss.usermodel.Row;
 import org.apache.poi.ss.usermodel.Sheet;
-import org.apache.poi.util.NullPrintStream;
+import org.apache.commons.io.output.NullPrintStream;
 import org.junit.jupiter.api.Test;
 
 class HSSFFileHandler extends SpreadsheetHandler {
diff --git a/poi-integration/src/test/java/org/apache/poi/stress/POIFSFileHandler.java b/poi-integration/src/test/java/org/apache/poi/stress/POIFSFileHandler.java
index b92f91f5f9..d492979992 100644
--- a/poi-integration/src/test/java/org/apache/poi/stress/POIFSFileHandler.java
+++ b/poi-integration/src/test/java/org/apache/poi/stress/POIFSFileHandler.java
@@ -18,13 +18,12 @@ package org.apache.poi.stress;
 
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.IOException;
 import java.io.InputStream;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.POIDocument;
 import org.apache.poi.hpsf.extractor.HPSFPropertiesExtractor;
 import org.apache.poi.poifs.filesystem.POIFSFileSystem;
@@ -58,13 +57,14 @@ class POIFSFileHandler extends AbstractFileHandler {
 	}
 
 	protected void handlePOIDocument(POIDocument doc) throws Exception {
-		ByteArrayOutputStream out = new ByteArrayOutputStream();
-		doc.write(out);
+		try (UnsynchronizedByteArrayOutputStream out = new UnsynchronizedByteArrayOutputStream()) {
+            doc.write(out);
 
-		ByteArrayInputStream in = new ByteArrayInputStream(out.toByteArray());
-		POIFSFileSystem fs = new POIFSFileSystem(in);
-		handlePOIFSFileSystem(fs);
-		fs.close();
+            try (InputStream in = out.toInputStream();
+                POIFSFileSystem fs = new POIFSFileSystem(in)) {
+                handlePOIFSFileSystem(fs);
+            }
+        }
 	}
 
     // a test-case to test this locally without executing the full TestAllFiles
diff --git a/poi-integration/src/test/java/org/apache/poi/stress/SlideShowHandler.java b/poi-integration/src/test/java/org/apache/poi/stress/SlideShowHandler.java
index 9a1defbf21..ec291e1c0b 100644
--- a/poi-integration/src/test/java/org/apache/poi/stress/SlideShowHandler.java
+++ b/poi-integration/src/test/java/org/apache/poi/stress/SlideShowHandler.java
@@ -23,11 +23,10 @@ import java.awt.Dimension;
 import java.awt.Graphics2D;
 import java.awt.RenderingHints;
 import java.awt.image.BufferedImage;
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.lang.ref.WeakReference;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.sl.draw.Drawable;
 import org.apache.poi.sl.usermodel.GroupShape;
 import org.apache.poi.sl.usermodel.Notes;
@@ -40,7 +39,6 @@ import org.apache.poi.sl.usermodel.SlideShowFactory;
 import org.apache.poi.sl.usermodel.TextParagraph;
 import org.apache.poi.sl.usermodel.TextRun;
 import org.apache.poi.sl.usermodel.TextShape;
-import org.junit.jupiter.api.Assumptions;
 import org.junit.platform.commons.util.ExceptionUtils;
 
 public abstract class SlideShowHandler extends POIFSFileHandler {
@@ -51,29 +49,18 @@ public abstract class SlideShowHandler extends POIFSFileHandler {
         readPictures(ss);
 
         // write out the file
-        ByteArrayOutputStream out = writeToArray(ss);
+        UnsynchronizedByteArrayOutputStream out = new UnsynchronizedByteArrayOutputStream();
+        ss.write(out);
 
         readContent(ss);
 
         // read in the written file
-        try (SlideShow<?, ?> read = SlideShowFactory.create(new ByteArrayInputStream(out.toByteArray()))) {
+        try (SlideShow<?, ?> read = SlideShowFactory.create(out.toInputStream())) {
             assertNotNull(read);
             readContent(read);
         }
     }
 
-    private ByteArrayOutputStream writeToArray(SlideShow<?,?> ss) throws IOException {
-        ByteArrayOutputStream stream = new ByteArrayOutputStream();
-        try {
-            ss.write(stream);
-        } finally {
-            stream.close();
-        }
-
-        return stream;
-    }
-
-
     private void readContent(SlideShow<?,?> ss) {
         for (Slide<?,?> s : ss.getSlides()) {
             s.getTitle();
diff --git a/poi-integration/src/test/java/org/apache/poi/stress/SpreadsheetHandler.java b/poi-integration/src/test/java/org/apache/poi/stress/SpreadsheetHandler.java
index dcee603bf2..341902b4ea 100644
--- a/poi-integration/src/test/java/org/apache/poi/stress/SpreadsheetHandler.java
+++ b/poi-integration/src/test/java/org/apache/poi/stress/SpreadsheetHandler.java
@@ -18,10 +18,9 @@ package org.apache.poi.stress;
 
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.ss.extractor.EmbeddedData;
 import org.apache.poi.ss.extractor.EmbeddedExtractor;
 import org.apache.poi.ss.usermodel.Cell;
@@ -45,10 +44,10 @@ public abstract class SpreadsheetHandler extends AbstractFileHandler {
 		readContent(wb);
 
 		// write once more
-		ByteArrayOutputStream out = writeToArray(wb);
+		UnsynchronizedByteArrayOutputStream out = writeToArray(wb);
 
 		// read in the written file
-		Workbook read = WorkbookFactory.create(new ByteArrayInputStream(out.toByteArray()));
+		Workbook read = WorkbookFactory.create(out.toInputStream());
 
 		assertNotNull(read);
 
@@ -61,14 +60,9 @@ public abstract class SpreadsheetHandler extends AbstractFileHandler {
 		read.close();
 	}
 
-	private ByteArrayOutputStream writeToArray(Workbook wb) throws IOException {
-		ByteArrayOutputStream stream = new ByteArrayOutputStream();
-		try {
-			wb.write(stream);
-		} finally {
-			stream.close();
-		}
-
+	private UnsynchronizedByteArrayOutputStream writeToArray(Workbook wb) throws IOException {
+		UnsynchronizedByteArrayOutputStream stream = new UnsynchronizedByteArrayOutputStream();
+		wb.write(stream);
 		return stream;
 	}
 
diff --git a/poi-integration/src/test/java/org/apache/poi/stress/XSSFBFileHandler.java b/poi-integration/src/test/java/org/apache/poi/stress/XSSFBFileHandler.java
index 1bc23c49ed..dd25e4148d 100644
--- a/poi-integration/src/test/java/org/apache/poi/stress/XSSFBFileHandler.java
+++ b/poi-integration/src/test/java/org/apache/poi/stress/XSSFBFileHandler.java
@@ -17,7 +17,6 @@
 package org.apache.poi.stress;
 
 import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.IOException;
@@ -40,10 +39,8 @@ class XSSFBFileHandler extends AbstractFileHandler {
 
     @Override
     public void handleFile(InputStream stream, String path) throws Exception {
-        ByteArrayOutputStream out = new ByteArrayOutputStream();
-        IOUtils.copy(stream, out);
+        byte[] bytes = IOUtils.toByteArray(stream);
 
-        final byte[] bytes = out.toByteArray();
         try (OPCPackage opcPackage = OPCPackage.open(new ByteArrayInputStream(bytes))) {
             testOne(opcPackage);
         }
diff --git a/poi-integration/src/test/java/org/apache/poi/stress/XSSFFileHandler.java b/poi-integration/src/test/java/org/apache/poi/stress/XSSFFileHandler.java
index beb3a8edf8..6f9571564f 100644
--- a/poi-integration/src/test/java/org/apache/poi/stress/XSSFFileHandler.java
+++ b/poi-integration/src/test/java/org/apache/poi/stress/XSSFFileHandler.java
@@ -16,14 +16,13 @@
 ==================================================================== */
 package org.apache.poi.stress;
 
+import static org.apache.commons.io.output.NullOutputStream.NULL_OUTPUT_STREAM;
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 import static org.junit.jupiter.api.Assumptions.assumeFalse;
 
 import java.io.BufferedInputStream;
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.IOException;
@@ -35,6 +34,8 @@ import java.util.Set;
 
 import javax.xml.transform.TransformerException;
 
+import org.apache.commons.io.output.NullPrintStream;
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.EncryptedDocumentException;
 import org.apache.poi.examples.ss.ExcelComparator;
 import org.apache.poi.examples.xssf.eventusermodel.FromHowTo;
@@ -50,7 +51,6 @@ import org.apache.poi.poifs.crypt.EncryptionInfo;
 import org.apache.poi.poifs.filesystem.POIFSFileSystem;
 import org.apache.poi.ss.usermodel.Sheet;
 import org.apache.poi.util.IOUtils;
-import org.apache.poi.util.NullPrintStream;
 import org.apache.poi.xssf.eventusermodel.XSSFReader;
 import org.apache.poi.xssf.extractor.XSSFExportToXml;
 import org.apache.poi.xssf.usermodel.XSSFMap;
@@ -70,12 +70,12 @@ class XSSFFileHandler extends SpreadsheetHandler {
 
         // make sure the potentially large byte-array is freed up quickly again
         {
-            ByteArrayOutputStream out = new ByteArrayOutputStream();
+
+            UnsynchronizedByteArrayOutputStream out = new UnsynchronizedByteArrayOutputStream();
             IOUtils.copy(stream, out);
-            ByteArrayInputStream bytes = new ByteArrayInputStream(out.toByteArray());
 
             if (pass != null) {
-                POIFSFileSystem poifs = new POIFSFileSystem(bytes);
+                POIFSFileSystem poifs = new POIFSFileSystem(out.toInputStream());
                 EncryptionInfo ei = new EncryptionInfo(poifs);
                 Decryptor dec = ei.getDecryptor();
                 try {
@@ -91,11 +91,9 @@ class XSSFFileHandler extends SpreadsheetHandler {
                 IOUtils.copy(is, out);
                 is.close();
                 poifs.close();
-                bytes = new ByteArrayInputStream(out.toByteArray());
             }
-            checkXSSFReader(OPCPackage.open(bytes));
-            bytes.reset();
-            wb = new XSSFWorkbook(bytes);
+            checkXSSFReader(OPCPackage.open(out.toInputStream()));
+            wb = new XSSFWorkbook(out.toInputStream());
         }
 
         // use the combined handler for HSSF/XSSF
@@ -157,9 +155,7 @@ class XSSFFileHandler extends SpreadsheetHandler {
             TransformerException {
         for (XSSFMap map : wb.getCustomXMLMappings()) {
             XSSFExportToXml exporter = new XSSFExportToXml(map);
-
-            ByteArrayOutputStream os = new ByteArrayOutputStream();
-            exporter.exportToXML(os, true);
+            exporter.exportToXML(NULL_OUTPUT_STREAM, true);
         }
     }
 
diff --git a/poi-ooxml/src/main/java/org/apache/poi/openxml4j/opc/OPCPackage.java b/poi-ooxml/src/main/java/org/apache/poi/openxml4j/opc/OPCPackage.java
index 9c92fb5f3e..70b50e4d63 100644
--- a/poi-ooxml/src/main/java/org/apache/poi/openxml4j/opc/OPCPackage.java
+++ b/poi-ooxml/src/main/java/org/apache/poi/openxml4j/opc/OPCPackage.java
@@ -898,16 +898,12 @@ public abstract class OPCPackage implements RelationshipSource, Closeable {
 		}
 		// Extract the zip entry content to put it in the part content
 		if (content != null) {
-			try {
-				OutputStream partOutput = addedPart.getOutputStream();
+			try (OutputStream partOutput = addedPart.getOutputStream()) {
 				if (partOutput == null) {
 					return null;
 				}
-
-				partOutput.write(content.toByteArray(), 0, content.size());
-				partOutput.close();
-
-			} catch (IOException ioe) {
+				content.writeTo(partOutput);
+			} catch (IOException ignored) {
 				return null;
 			}
 		} else {
diff --git a/poi-ooxml/src/main/java/org/apache/poi/openxml4j/opc/internal/MemoryPackagePart.java b/poi-ooxml/src/main/java/org/apache/poi/openxml4j/opc/internal/MemoryPackagePart.java
index 0df7364903..c4ab456fd8 100644
--- a/poi-ooxml/src/main/java/org/apache/poi/openxml4j/opc/internal/MemoryPackagePart.java
+++ b/poi-ooxml/src/main/java/org/apache/poi/openxml4j/opc/internal/MemoryPackagePart.java
@@ -18,11 +18,11 @@
 package org.apache.poi.openxml4j.opc.internal;
 
 import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.openxml4j.exceptions.InvalidFormatException;
 import org.apache.poi.openxml4j.exceptions.OpenXML4JException;
 import org.apache.poi.openxml4j.opc.OPCPackage;
@@ -113,17 +113,15 @@ public final class MemoryPackagePart extends PackagePart {
 
 	@Override
 	public boolean load(InputStream ios) throws InvalidFormatException {
-	   // Grab the data
-	   ByteArrayOutputStream baos = new ByteArrayOutputStream();
-	   try {
+	   try (UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream()) {
+		   // Grab the data
 	      IOUtils.copy(ios, baos);
+		   // Save it
+		   data = baos.toByteArray();
 	   } catch(IOException e) {
 	      throw new InvalidFormatException(e.getMessage());
 	   }
 
-	   // Save it
-	   data = baos.toByteArray();
-
 	   // All done
 	   return true;
 	}
diff --git a/poi-ooxml/src/main/java/org/apache/poi/openxml4j/opc/internal/MemoryPackagePartOutputStream.java b/poi-ooxml/src/main/java/org/apache/poi/openxml4j/opc/internal/MemoryPackagePartOutputStream.java
index 5cd07238e3..7fce830721 100644
--- a/poi-ooxml/src/main/java/org/apache/poi/openxml4j/opc/internal/MemoryPackagePartOutputStream.java
+++ b/poi-ooxml/src/main/java/org/apache/poi/openxml4j/opc/internal/MemoryPackagePartOutputStream.java
@@ -17,22 +17,23 @@
 
 package org.apache.poi.openxml4j.opc.internal;
 
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.OutputStream;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
+
 /**
  * Build an output stream for MemoryPackagePart.
  */
 public final class MemoryPackagePartOutputStream extends OutputStream {
 
-	private MemoryPackagePart _part;
+	private final MemoryPackagePart _part;
 
-	private ByteArrayOutputStream _buff;
+	private final UnsynchronizedByteArrayOutputStream _buff;
 
 	public MemoryPackagePartOutputStream(MemoryPackagePart part) {
 		this._part = part;
-		_buff = new ByteArrayOutputStream();
+		_buff = new UnsynchronizedByteArrayOutputStream();
 	}
 
 	@Override
diff --git a/poi-ooxml/src/main/java/org/apache/poi/openxml4j/opc/internal/PackagePropertiesPart.java b/poi-ooxml/src/main/java/org/apache/poi/openxml4j/opc/internal/PackagePropertiesPart.java
index 0658a03c6d..d6a625baeb 100644
--- a/poi-ooxml/src/main/java/org/apache/poi/openxml4j/opc/internal/PackagePropertiesPart.java
+++ b/poi-ooxml/src/main/java/org/apache/poi/openxml4j/opc/internal/PackagePropertiesPart.java
@@ -202,8 +202,8 @@ public final class PackagePropertiesPart extends PackagePart implements PackageP
     /**
      * Get the category property.
      *
-     * @see org.apache.poi.openxml4j.opc.PackageProperties#getCategoryProperty()
      */
+    @Override
     public Optional<String> getCategoryProperty() {
         return category;
     }
@@ -211,8 +211,8 @@ public final class PackagePropertiesPart extends PackagePart implements PackageP
     /**
      * Get content status.
      *
-     * @see org.apache.poi.openxml4j.opc.PackageProperties#getContentStatusProperty()
      */
+    @Override
     public Optional<String> getContentStatusProperty() {
         return contentStatus;
     }
@@ -220,8 +220,8 @@ public final class PackagePropertiesPart extends PackagePart implements PackageP
     /**
      * Get content type.
      *
-     * @see org.apache.poi.openxml4j.opc.PackageProperties#getContentTypeProperty()
      */
+    @Override
     public Optional<String> getContentTypeProperty() {
         return contentType;
     }
@@ -229,8 +229,8 @@ public final class PackagePropertiesPart extends PackagePart implements PackageP
     /**
      * Get created date.
      *
-     * @see org.apache.poi.openxml4j.opc.PackageProperties#getCreatedProperty()
      */
+    @Override
     public Optional<Date> getCreatedProperty() {
         return created;
     }
@@ -247,8 +247,8 @@ public final class PackagePropertiesPart extends PackagePart implements PackageP
     /**
      * Get creator.
      *
-     * @see org.apache.poi.openxml4j.opc.PackageProperties#getCreatorProperty()
      */
+    @Override
     public Optional<String> getCreatorProperty() {
         return creator;
     }
@@ -256,8 +256,8 @@ public final class PackagePropertiesPart extends PackagePart implements PackageP
     /**
      * Get description.
      *
-     * @see org.apache.poi.openxml4j.opc.PackageProperties#getDescriptionProperty()
      */
+    @Override
     public Optional<String> getDescriptionProperty() {
         return description;
     }
@@ -265,8 +265,8 @@ public final class PackagePropertiesPart extends PackagePart implements PackageP
     /**
      * Get identifier.
      *
-     * @see org.apache.poi.openxml4j.opc.PackageProperties#getIdentifierProperty()
      */
+    @Override
     public Optional<String> getIdentifierProperty() {
         return identifier;
     }
@@ -274,8 +274,8 @@ public final class PackagePropertiesPart extends PackagePart implements PackageP
     /**
      * Get keywords.
      *
-     * @see org.apache.poi.openxml4j.opc.PackageProperties#getKeywordsProperty()
      */
+    @Override
     public Optional<String> getKeywordsProperty() {
         return keywords;
     }
@@ -283,8 +283,8 @@ public final class PackagePropertiesPart extends PackagePart implements PackageP
     /**
      * Get the language.
      *
-     * @see org.apache.poi.openxml4j.opc.PackageProperties#getLanguageProperty()
      */
+    @Override
     public Optional<String> getLanguageProperty() {
         return language;
     }
@@ -292,8 +292,8 @@ public final class PackagePropertiesPart extends PackagePart implements PackageP
     /**
      * Get the author of last modifications.
      *
-     * @see org.apache.poi.openxml4j.opc.PackageProperties#getLastModifiedByProperty()
      */
+    @Override
     public Optional<String> getLastModifiedByProperty() {
         return lastModifiedBy;
     }
@@ -301,8 +301,8 @@ public final class PackagePropertiesPart extends PackagePart implements PackageP
     /**
      * Get last printed date.
      *
-     * @see org.apache.poi.openxml4j.opc.PackageProperties#getLastPrintedProperty()
      */
+    @Override
     public Optional<Date> getLastPrintedProperty() {
         return lastPrinted;
     }
@@ -319,8 +319,8 @@ public final class PackagePropertiesPart extends PackagePart implements PackageP
     /**
      * Get modified date.
      *
-     * @see org.apache.poi.openxml4j.opc.PackageProperties#getModifiedProperty()
      */
+    @Override
     public Optional<Date> getModifiedProperty() {
         return modified;
     }
@@ -340,8 +340,8 @@ public final class PackagePropertiesPart extends PackagePart implements PackageP
     /**
      * Get revision.
      *
-     * @see org.apache.poi.openxml4j.opc.PackageProperties#getRevisionProperty()
      */
+    @Override
     public Optional<String> getRevisionProperty() {
         return revision;
     }
@@ -349,8 +349,8 @@ public final class PackagePropertiesPart extends PackagePart implements PackageP
     /**
      * Get subject.
      *
-     * @see org.apache.poi.openxml4j.opc.PackageProperties#getSubjectProperty()
      */
+    @Override
     public Optional<String> getSubjectProperty() {
         return subject;
     }
@@ -358,8 +358,8 @@ public final class PackagePropertiesPart extends PackagePart implements PackageP
     /**
      * Get title.
      *
-     * @see org.apache.poi.openxml4j.opc.PackageProperties#getTitleProperty()
      */
+    @Override
     public Optional<String> getTitleProperty() {
         return title;
     }
@@ -367,8 +367,8 @@ public final class PackagePropertiesPart extends PackagePart implements PackageP
     /**
      * Get version.
      *
-     * @see org.apache.poi.openxml4j.opc.PackageProperties#getVersionProperty()
      */
+    @Override
     public Optional<String> getVersionProperty() {
         return version;
     }
@@ -376,8 +376,8 @@ public final class PackagePropertiesPart extends PackagePart implements PackageP
     /**
      * Set the category.
      *
-     * @see org.apache.poi.openxml4j.opc.PackageProperties#setCategoryProperty(java.lang.String)
      */
+    @Override
     public void setCategoryProperty(String category) {
         this.category = setStringValue(category);
     }
@@ -385,15 +385,15 @@ public final class PackagePropertiesPart extends PackagePart implements PackageP
     /**
      * Set the category.
      *
-     * @see org.apache.poi.openxml4j.opc.PackageProperties#setCategoryProperty(java.util.Optional)
      */
+    @Override
     public void setCategoryProperty(Optional<String> category) { this.category = category; }
 
     /**
      * Set the content status.
      *
-     * @see org.apache.poi.openxml4j.opc.PackageProperties#setContentStatusProperty(java.lang.String)
      */
+    @Override
     public void setContentStatusProperty(String contentStatus) {
         this.contentStatus = setStringValue(contentStatus);
     }
@@ -401,15 +401,15 @@ public final class PackagePropertiesPart extends PackagePart implements PackageP
     /**
      * Set the content status.
      *
-     * @see org.apache.poi.openxml4j.opc.PackageProperties#setContentStatusProperty(java.util.Optional)
      */
+    @Override
     public void setContentStatusProperty(Optional<String> contentStatus) { this.contentStatus = contentStatus; }
 
     /**
      * Set the content type.
      *
-     * @see org.apache.poi.openxml4j.opc.PackageProperties#setContentTypeProperty(java.lang.String)
      */
+    @Override
     public void setContentTypeProperty(String contentType) {
         this.contentType = setStringValue(contentType);
     }
@@ -417,8 +417,8 @@ public final class PackagePropertiesPart extends PackagePart implements PackageP
     /**
      * Set the content type.
      *
-     * @see org.apache.poi.openxml4j.opc.PackageProperties#setContentTypeProperty(java.util.Optional)
      */
+    @Override
     public void setContentTypeProperty(Optional<String> contentType) { this.contentType = contentType; }
 
     /**
@@ -426,6 +426,7 @@ public final class PackagePropertiesPart extends PackagePart implements PackageP
      *
      * @see org.apache.poi.openxml4j.opc.PackageProperties#setCreatedProperty(java.util.Optional)
      */
+    @Override
     public void setCreatedProperty(String created) {
         try {
             this.created = setDateValue(created);
@@ -437,8 +438,8 @@ public final class PackagePropertiesPart extends PackagePart implements PackageP
     /**
      * Set the created date.
      *
-     * @see org.apache.poi.openxml4j.opc.PackageProperties#setCreatedProperty(java.util.Optional)
      */
+    @Override
     public void setCreatedProperty(Optional<Date> created) {
         if (created.isPresent())
             this.created = created;
@@ -447,8 +448,8 @@ public final class PackagePropertiesPart extends PackagePart implements PackageP
     /**
      * Set the creator.
      *
-     * @see org.apache.poi.openxml4j.opc.PackageProperties#setCreatorProperty(java.lang.String)
      */
+    @Override
     public void setCreatorProperty(String creator) {
         this.creator = setStringValue(creator);
     }
@@ -456,15 +457,15 @@ public final class PackagePropertiesPart extends PackagePart implements PackageP
     /**
      * Set the creator.
      *
-     * @see org.apache.poi.openxml4j.opc.PackageProperties#setCreatorProperty(java.util.Optional)
      */
+    @Override
     public void setCreatorProperty(Optional<String> creator) { this.creator = creator; }
 
     /**
      * Set the description.
      *
-     * @see org.apache.poi.openxml4j.opc.PackageProperties#setDescriptionProperty(java.lang.String)
      */
+    @Override
     public void setDescriptionProperty(String description) {
         this.description = setStringValue(description);
     }
@@ -472,15 +473,15 @@ public final class PackagePropertiesPart extends PackagePart implements PackageP
     /**
      * Set the description.
      *
-     * @see org.apache.poi.openxml4j.opc.PackageProperties#setDescriptionProperty(java.util.Optional)
      */
+    @Override
     public void setDescriptionProperty(Optional<String> description) { this.description = description; }
 
     /**
      * Set identifier.
      *
-     * @see org.apache.poi.openxml4j.opc.PackageProperties#setIdentifierProperty(java.lang.String)
      */
+    @Override
     public void setIdentifierProperty(String identifier) {
         this.identifier = setStringValue(identifier);
     }
@@ -488,15 +489,15 @@ public final class PackagePropertiesPart extends PackagePart implements PackageP
     /**
      * Set identifier.
      *
-     * @see org.apache.poi.openxml4j.opc.PackageProperties#setIdentifierProperty(java.util.Optional)
      */
+    @Override
     public void setIdentifierProperty(Optional<String> identifier) { this.identifier = identifier; }
 
     /**
      * Set keywords.
      *
-     * @see org.apache.poi.openxml4j.opc.PackageProperties#setKeywordsProperty(java.lang.String)
      */
+    @Override
     public void setKeywordsProperty(String keywords) {
         this.keywords = setStringValue(keywords);
     }
@@ -504,15 +505,15 @@ public final class PackagePropertiesPart extends PackagePart implements PackageP
     /**
      * Set keywords.
      *
-     * @see org.apache.poi.openxml4j.opc.PackageProperties#setKeywordsProperty(java.util.Optional)
      */
+    @Override
     public void setKeywordsProperty(Optional<String> keywords) { this.keywords = keywords; }
 
     /**
      * Set language.
      *
-     * @see org.apache.poi.openxml4j.opc.PackageProperties#setLanguageProperty(java.lang.String)
      */
+    @Override
     public void setLanguageProperty(String language) {
         this.language = setStringValue(language);
     }
@@ -520,15 +521,15 @@ public final class PackagePropertiesPart extends PackagePart implements PackageP
     /**
      * Set language.
      *
-     * @see org.apache.poi.openxml4j.opc.PackageProperties#setLanguageProperty(java.util.Optional)
      */
+    @Override
     public void setLanguageProperty(Optional<String> language) { this.language = language; }
 
     /**
      * Set last modifications author.
      *
-     * @see org.apache.poi.openxml4j.opc.PackageProperties#setLastModifiedByProperty(java.lang.String)
      */
+    @Override
     public void setLastModifiedByProperty(String lastModifiedBy) {
         this.lastModifiedBy = setStringValue(lastModifiedBy);
     }
@@ -536,8 +537,8 @@ public final class PackagePropertiesPart extends PackagePart implements PackageP
     /**
      * Set last modifications author.
      *
-     * @see org.apache.poi.openxml4j.opc.PackageProperties#setLastModifiedByProperty(java.util.Optional)
      */
+    @Override
     public void setLastModifiedByProperty(Optional<String> lastModifiedBy) {
         this.lastModifiedBy = lastModifiedBy;
     }
@@ -547,6 +548,7 @@ public final class PackagePropertiesPart extends PackagePart implements PackageP
      *
      * @see org.apache.poi.openxml4j.opc.PackageProperties#setLastPrintedProperty(java.util.Optional)
      */
+    @Override
     public void setLastPrintedProperty(String lastPrinted) {
         try {
             this.lastPrinted = setDateValue(lastPrinted);
@@ -559,8 +561,8 @@ public final class PackagePropertiesPart extends PackagePart implements PackageP
     /**
      * Set last printed date.
      *
-     * @see org.apache.poi.openxml4j.opc.PackageProperties#setLastPrintedProperty(java.util.Optional)
      */
+    @Override
     public void setLastPrintedProperty(Optional<Date> lastPrinted) {
         if (lastPrinted.isPresent())
             this.lastPrinted = lastPrinted;
@@ -571,6 +573,7 @@ public final class PackagePropertiesPart extends PackagePart implements PackageP
      *
      * @see org.apache.poi.openxml4j.opc.PackageProperties#setModifiedProperty(java.util.Optional)
      */
+    @Override
     public void setModifiedProperty(String modified) {
         try {
             this.modified = setDateValue(modified);
@@ -583,8 +586,8 @@ public final class PackagePropertiesPart extends PackagePart implements PackageP
     /**
      * Set last modification date.
      *
-     * @see org.apache.poi.openxml4j.opc.PackageProperties#setModifiedProperty(java.util.Optional)
      */
+    @Override
     public void setModifiedProperty(Optional<Date> modified) {
         if (modified.isPresent())
             this.modified = modified;
@@ -593,23 +596,23 @@ public final class PackagePropertiesPart extends PackagePart implements PackageP
     /**
      * Set revision.
      *
-     * @see org.apache.poi.openxml4j.opc.PackageProperties#setRevisionProperty(java.util.Optional)
      */
+    @Override
     public void setRevisionProperty(Optional<String> revision) { this.revision = revision; }
 
     /**
      * Set revision.
      *
-     * @see org.apache.poi.openxml4j.opc.PackageProperties#setRevisionProperty(java.lang.String)
      */
+    @Override
     public void setRevisionProperty(String revision) {
         this.revision = setStringValue(revision);
     }
     /**
      * Set subject.
      *
-     * @see org.apache.poi.openxml4j.opc.PackageProperties#setSubjectProperty(java.lang.String)
      */
+    @Override
     public void setSubjectProperty(String subject) {
         this.subject = setStringValue(subject);
     }
@@ -617,15 +620,15 @@ public final class PackagePropertiesPart extends PackagePart implements PackageP
     /**
      * Set subject.
      *
-     * @see org.apache.poi.openxml4j.opc.PackageProperties#setSubjectProperty(java.util.Optional)
      */
+    @Override
     public void setSubjectProperty(Optional<String> subject) { this.subject = subject; }
 
     /**
      * Set title.
      *
-     * @see org.apache.poi.openxml4j.opc.PackageProperties#setTitleProperty(java.lang.String)
      */
+    @Override
     public void setTitleProperty(String title) {
         this.title = setStringValue(title);
     }
@@ -633,15 +636,15 @@ public final class PackagePropertiesPart extends PackagePart implements PackageP
     /**
      * Set title.
      *
-     * @see org.apache.poi.openxml4j.opc.PackageProperties#setTitleProperty(java.util.Optional)
      */
+    @Override
     public void setTitleProperty(Optional<String> title) { this.title = title; }
 
     /**
      * Set version.
      *
-     * @see org.apache.poi.openxml4j.opc.PackageProperties#setVersionProperty(java.lang.String)
      */
+    @Override
     public void setVersionProperty(String version) {
         this.version = setStringValue(version);
     }
@@ -649,12 +652,12 @@ public final class PackagePropertiesPart extends PackagePart implements PackageP
     /**
      * Set version.
      *
-     * @see org.apache.poi.openxml4j.opc.PackageProperties#setVersionProperty(java.util.Optional)
      */
+    @Override
     public void setVersionProperty(Optional<String> version) { this.version = version; }
 
     /**
-     * Convert a string value into a Optional<String>
+     * Convert a string value into a {@code Optional<String>}
      */
     private Optional<String> setStringValue(String s) {
         if (s == null || s.isEmpty()) {
@@ -664,7 +667,7 @@ public final class PackagePropertiesPart extends PackagePart implements PackageP
     }
 
     /**
-     * Convert a string value represented a date into a Optional<Date>.
+     * Convert a string value represented a date into a {@code Optional<Date>}
      *
      * @throws InvalidFormatException
      *             Throws if the date format isnot valid.
@@ -707,7 +710,7 @@ public final class PackagePropertiesPart extends PackagePart implements PackageP
     }
 
     /**
-     * Convert a Optional<Date> into a String.
+     * Convert a {@code Optional<Date>} into a String.
      *
      * @param d
      *            The Date to convert.
diff --git a/poi-ooxml/src/main/java/org/apache/poi/poifs/crypt/dsig/DigestOutputStream.java b/poi-ooxml/src/main/java/org/apache/poi/poifs/crypt/dsig/DigestOutputStream.java
index f8ad4a33e5..35e0f4924a 100644
--- a/poi-ooxml/src/main/java/org/apache/poi/poifs/crypt/dsig/DigestOutputStream.java
+++ b/poi-ooxml/src/main/java/org/apache/poi/poifs/crypt/dsig/DigestOutputStream.java
@@ -17,7 +17,6 @@
 
 package org.apache.poi.poifs.crypt.dsig;
 
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.OutputStream;
 import java.security.GeneralSecurityException;
@@ -26,6 +25,7 @@ import java.security.PrivateKey;
 
 import javax.crypto.Cipher;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.EncryptedDocumentException;
 import org.apache.poi.poifs.crypt.ChainingMode;
 import org.apache.poi.poifs.crypt.CipherAlgorithm;
@@ -54,7 +54,7 @@ import org.ietf.jgss.Oid;
         }
         md = CryptoFunctions.getMessageDigest(algo);
     }
-    
+
     @Override
     public void write(final int b) throws IOException {
         md.update((byte)b);
@@ -66,7 +66,7 @@ import org.ietf.jgss.Oid;
     }
 
     public byte[] sign() throws IOException, GeneralSecurityException {
-        ByteArrayOutputStream bos = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream();
         bos.write(getHashMagic());
         bos.write(md.digest());
 
@@ -74,7 +74,7 @@ import org.ietf.jgss.Oid;
             , ChainingMode.ecb, null, Cipher.ENCRYPT_MODE, "PKCS1Padding");
         return cipher.doFinal(bos.toByteArray());
     }
-    
+
     static boolean isMSCapi(final PrivateKey key) {
         return key != null && key.getClass().getName().contains("mscapi");
     }
@@ -84,7 +84,7 @@ import org.ietf.jgss.Oid;
      * Each digest method has its own ASN1 header
      *
      * @return the ASN1 header bytes for the signatureValue / digestInfo
-     * 
+     *
      * @see <a href="https://tools.ietf.org/html/rfc2313#section-10.1.2">Data encoding</a>
      */
     byte[] getHashMagic() {
@@ -94,7 +94,7 @@ import org.ietf.jgss.Oid;
         try {
             final byte[] oidBytes = new Oid(algo.rsaOid).getDER();
 
-            final ByteArrayOutputStream bos = new ByteArrayOutputStream();
+            final UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream();
             bos.write(0x30);
             bos.write(algo.hashSize+oidBytes.length+6);
             bos.write(0x30);
@@ -102,7 +102,7 @@ import org.ietf.jgss.Oid;
             bos.write(oidBytes);
             bos.write(new byte[] {5,0,4});
             bos.write(algo.hashSize);
-            
+
             return bos.toByteArray();
         } catch (GSSException|IOException e) {
             throw new IllegalStateException(e);
diff --git a/poi-ooxml/src/main/java/org/apache/poi/poifs/crypt/dsig/OOXMLURIDereferencer.java b/poi-ooxml/src/main/java/org/apache/poi/poifs/crypt/dsig/OOXMLURIDereferencer.java
index d38088c68c..ff977fa45a 100644
--- a/poi-ooxml/src/main/java/org/apache/poi/poifs/crypt/dsig/OOXMLURIDereferencer.java
+++ b/poi-ooxml/src/main/java/org/apache/poi/poifs/crypt/dsig/OOXMLURIDereferencer.java
@@ -24,8 +24,6 @@
 
 package org.apache.poi.poifs.crypt.dsig;
 
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.net.URI;
@@ -38,6 +36,7 @@ import javax.xml.crypto.URIReference;
 import javax.xml.crypto.URIReferenceException;
 import javax.xml.crypto.XMLCryptoContext;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.poi.openxml4j.exceptions.InvalidFormatException;
@@ -60,6 +59,7 @@ public class OOXMLURIDereferencer implements URIDereferencer {
         baseUriDereferencer = signatureInfo.getSignatureFactory().getURIDereferencer();
     }
 
+    @Override
     public Data dereference(URIReference uriReference, XMLCryptoContext context) throws URIReferenceException {
         if (uriReference == null) {
             throw new NullPointerException("URIReference cannot be null - call setSignatureInfo(...) before");
@@ -90,12 +90,12 @@ public class OOXMLURIDereferencer implements URIDereferencer {
                 // although xmlsec has an option to ignore line breaks, currently this
                 // only affects .rels files, so we only modify these
                 // http://stackoverflow.com/questions/4728300
-                ByteArrayOutputStream bos = new ByteArrayOutputStream();
+                UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream();
                 for (int ch; (ch = dataStream.read()) != -1; ) {
                     if (ch == 10 || ch == 13) continue;
                     bos.write(ch);
                 }
-                dataStream = new ByteArrayInputStream(bos.toByteArray());
+                dataStream = bos.toInputStream();
             }
         } catch (IOException e) {
             throw new URIReferenceException("I/O error: " + e.getMessage(), e);
diff --git a/poi-ooxml/src/main/java/org/apache/poi/poifs/crypt/dsig/SignatureLine.java b/poi-ooxml/src/main/java/org/apache/poi/poifs/crypt/dsig/SignatureLine.java
index 06067ea531..34fc8d30d1 100644
--- a/poi-ooxml/src/main/java/org/apache/poi/poifs/crypt/dsig/SignatureLine.java
+++ b/poi-ooxml/src/main/java/org/apache/poi/poifs/crypt/dsig/SignatureLine.java
@@ -32,7 +32,6 @@ import java.awt.geom.AffineTransform;
 import java.awt.geom.Dimension2D;
 import java.awt.geom.Rectangle2D;
 import java.awt.image.BufferedImage;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.text.AttributedCharacterIterator;
 import java.text.AttributedString;
@@ -46,6 +45,7 @@ import com.microsoft.schemas.vml.CTGroup;
 import com.microsoft.schemas.vml.CTImageData;
 import com.microsoft.schemas.vml.CTShape;
 import com.microsoft.schemas.vml.STExt;
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.common.usermodel.PictureType;
 import org.apache.poi.hpsf.ClassID;
 import org.apache.poi.ooxml.POIXMLException;
@@ -290,7 +290,7 @@ public abstract class SignatureLine {
                 xsl.setSuggestedsigneremail(suggestedSignerEmail);
             }
             if (setupId == null) {
-                setupId = new ClassID("{"+ UUID.randomUUID().toString()+"}");
+                setupId = new ClassID("{"+ UUID.randomUUID() +"}");
             }
             xsl.setId(setupId.toString());
             xsl.setAllowcomments(STTrueFalse.T);
@@ -344,7 +344,7 @@ public abstract class SignatureLine {
         rnd.drawImage(gfx, new Rectangle2D.Double(0, 0, defaultWidth, defaultHeight));
         gfx.dispose();
 
-        ByteArrayOutputStream bos = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream();
         ImageIO.write(bi, "PNG", bos);
         return bos.toByteArray();
     }
@@ -429,7 +429,7 @@ public abstract class SignatureLine {
 
         gfx.dispose();
 
-        ByteArrayOutputStream bos = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream();
         ImageIO.write(bi, "PNG", bos);
         return bos.toByteArray();
     }
diff --git a/poi-ooxml/src/main/java/org/apache/poi/poifs/crypt/dsig/facets/XAdESXLSignatureFacet.java b/poi-ooxml/src/main/java/org/apache/poi/poifs/crypt/dsig/facets/XAdESXLSignatureFacet.java
index 3b00748156..5a82f4152c 100644
--- a/poi-ooxml/src/main/java/org/apache/poi/poifs/crypt/dsig/facets/XAdESXLSignatureFacet.java
+++ b/poi-ooxml/src/main/java/org/apache/poi/poifs/crypt/dsig/facets/XAdESXLSignatureFacet.java
@@ -28,7 +28,6 @@ import static org.apache.poi.ooxml.POIXMLTypeLoader.DEFAULT_XML_OPTIONS;
 import static org.apache.poi.poifs.crypt.dsig.facets.XAdESSignatureFacet.insertXChild;
 
 import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.math.BigInteger;
 import java.security.cert.CRLException;
@@ -47,6 +46,7 @@ import java.util.UUID;
 
 import javax.xml.crypto.MarshalException;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.poi.poifs.crypt.dsig.SignatureConfig;
@@ -104,8 +104,8 @@ public class XAdESXLSignatureFacet implements SignatureFacet {
 
         SignatureConfig signatureConfig = signatureInfo.getSignatureConfig();
 
-        QualifyingPropertiesDocument qualDoc = null;
-        QualifyingPropertiesType qualProps = null;
+        QualifyingPropertiesDocument qualDoc;
+        QualifyingPropertiesType qualProps;
 
         // check for XAdES-BES
         NodeList qualNl = document.getElementsByTagNameNS(XADES_132_NS, "QualifyingProperties");
@@ -289,7 +289,7 @@ public class XAdESXLSignatureFacet implements SignatureFacet {
     }
 
     public static byte[] getC14nValue(List<Node> nodeList, String c14nAlgoId) {
-        ByteArrayOutputStream c14nValue = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream c14nValue = new UnsynchronizedByteArrayOutputStream();
         try {
             for (Node node : nodeList) {
                 /*
diff --git a/poi-ooxml/src/main/java/org/apache/poi/poifs/crypt/dsig/services/TSPTimeStampService.java b/poi-ooxml/src/main/java/org/apache/poi/poifs/crypt/dsig/services/TSPTimeStampService.java
index e0746f60eb..40b05b483d 100644
--- a/poi-ooxml/src/main/java/org/apache/poi/poifs/crypt/dsig/services/TSPTimeStampService.java
+++ b/poi-ooxml/src/main/java/org/apache/poi/poifs/crypt/dsig/services/TSPTimeStampService.java
@@ -24,7 +24,8 @@
 
 package org.apache.poi.poifs.crypt.dsig.services;
 
-import java.io.ByteArrayOutputStream;
+import static org.apache.logging.log4j.util.Unbox.box;
+
 import java.io.IOException;
 import java.io.OutputStream;
 import java.math.BigInteger;
@@ -44,6 +45,7 @@ import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.SimpleMessage;
@@ -72,8 +74,6 @@ import org.bouncycastle.tsp.TimeStampRequestGenerator;
 import org.bouncycastle.tsp.TimeStampResponse;
 import org.bouncycastle.tsp.TimeStampToken;
 
-import static org.apache.logging.log4j.util.Unbox.box;
-
 /**
  * A TSP time-stamp service implementation.
  */
@@ -95,7 +95,8 @@ public class TSPTimeStampService implements TimeStampService {
         }
     }
 
-    @SuppressWarnings({"unchecked","squid:S2647"})
+    @Override
+    @SuppressWarnings({"squid:S2647"})
     public byte[] timeStamp(SignatureInfo signatureInfo, byte[] data, RevocationData revocationData) throws Exception {
         SignatureConfig signatureConfig = signatureInfo.getSignatureConfig();
 
@@ -124,7 +125,7 @@ public class TSPTimeStampService implements TimeStampService {
             proxy = new Proxy(Proxy.Type.HTTP, new InetSocketAddress(InetAddress.getByName(host), (port == -1 ? 80 : port)));
         }
 
-        ByteArrayOutputStream bos;
+        UnsynchronizedByteArrayOutputStream bos;
         String contentType;
         HttpURLConnection huc = (HttpURLConnection)new URL(signatureConfig.getTspUrl()).openConnection(proxy);
         try {
@@ -163,7 +164,7 @@ public class TSPTimeStampService implements TimeStampService {
                 throw new RuntimeException("missing Content-Type header");
             }
 
-            bos = new ByteArrayOutputStream();
+            bos = new UnsynchronizedByteArrayOutputStream();
             IOUtils.copy(huc.getInputStream(), bos);
             LOG.atDebug().log(() -> new SimpleMessage("response content: " + HexDump.dump(bos.toByteArray(), 0, 0)));
         } finally {
diff --git a/poi-ooxml/src/main/java/org/apache/poi/xslf/draw/SVGRenderExtension.java b/poi-ooxml/src/main/java/org/apache/poi/xslf/draw/SVGRenderExtension.java
index e6e72058b8..8dba51f77e 100644
--- a/poi-ooxml/src/main/java/org/apache/poi/xslf/draw/SVGRenderExtension.java
+++ b/poi-ooxml/src/main/java/org/apache/poi/xslf/draw/SVGRenderExtension.java
@@ -43,7 +43,6 @@ import java.awt.geom.Rectangle2D;
 import java.awt.image.BufferedImage;
 import java.awt.image.ColorModel;
 import java.awt.image.WritableRaster;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.lang.ref.WeakReference;
 import java.nio.charset.StandardCharsets;
@@ -60,6 +59,7 @@ import org.apache.batik.svggen.SVGGeneratorContext;
 import org.apache.batik.svggen.SVGGraphics2D;
 import org.apache.batik.svggen.SVGPaintDescriptor;
 import org.apache.batik.svggen.SVGTexturePaint;
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.sl.draw.BitmapImageRenderer;
 import org.apache.poi.sl.draw.DrawTexturePaint;
 import org.apache.poi.sl.draw.Drawable;
@@ -274,12 +274,12 @@ public class SVGRenderExtension extends DefaultExtensionHandler {
             null, SVG_VIEW_BOX_ATTRIBUTE, x+" "+ y+" "+ w+" "+h
         );
 
-        org.apache.poi.sl.usermodel.Shape slShape = fill.getShape();
+        org.apache.poi.sl.usermodel.Shape<?,?> slShape = fill.getShape();
 
         // TODO: the rotation handling is incomplete and the scale handling is missing
         //  see DrawTexturePaint on how to do it for AWT
         if (!fill.isRotatedWithShape() && slShape instanceof SimpleShape) {
-            double rot = ((SimpleShape)slShape).getRotation();
+            double rot = ((SimpleShape<?,?>)slShape).getRotation();
             if (rot != 0) {
                 setAttribute(genCtx, patternDef,
                     null, SVG_PATTERN_TRANSFORM_ATTRIBUTE, "rotate(" + genCtx.doubleString(-rot) + ")");
@@ -311,7 +311,7 @@ public class SVGRenderExtension extends DefaultExtensionHandler {
         }
         if (imgData == null) {
             BufferedImage bi = imgRdr.getImage();
-            ByteArrayOutputStream bos = new ByteArrayOutputStream();
+            UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream();
             try {
                 ImageIO.write(bi, "PNG", bos);
             } catch (IOException e) {
diff --git a/poi-ooxml/src/main/java/org/apache/poi/xslf/usermodel/XSLFObjectShape.java b/poi-ooxml/src/main/java/org/apache/poi/xslf/usermodel/XSLFObjectShape.java
index 8ee5017d1f..9b5b9d63dd 100644
--- a/poi-ooxml/src/main/java/org/apache/poi/xslf/usermodel/XSLFObjectShape.java
+++ b/poi-ooxml/src/main/java/org/apache/poi/xslf/usermodel/XSLFObjectShape.java
@@ -19,14 +19,14 @@
 
 package org.apache.poi.xslf.usermodel;
 
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
+import java.io.InputStream;
 import java.io.OutputStream;
 
 import javax.xml.namespace.QName;
 import javax.xml.stream.XMLStreamReader;
 
+import org.apache.commons.io.output.ByteArrayOutputStream;
 import org.apache.poi.hpsf.ClassID;
 import org.apache.poi.ooxml.POIXMLDocumentPart.RelationPart;
 import org.apache.poi.ooxml.POIXMLException;
@@ -68,7 +68,7 @@ public class XSLFObjectShape extends XSLFGraphicFrame implements ObjectShape<XSL
     private static final QName[] OLE_OBJ = { new QName(PML_NS, "oleObj") };
     private static final QName[] CT_PICTURE = { new QName(PML_NS, "pic") };
 
-    private CTOleObject _oleObject;
+    private final CTOleObject _oleObject;
     private XSLFPictureData _data;
 
     /*package*/ XSLFObjectShape(CTGraphicalObjectFrame shape, XSLFSheet sheet){
@@ -193,56 +193,45 @@ public class XSLFObjectShape extends XSLFGraphicFrame implements ObjectShape<XSL
         _oleObject.setProgId(md.getProgId());
         _oleObject.setName(md.getObjectName());
 
-        return new XSLFObjectOutputStream(rp.getDocumentPart().getPackagePart(),md);
+        return new ByteArrayOutputStream() {
+            @Override
+            public void close() throws IOException {
+                addUpdatedData(rp.getDocumentPart().getPackagePart(),md,this);
+            }
+        };
     }
 
-    private static class XSLFObjectOutputStream extends ByteArrayOutputStream {
-        final PackagePart objectPart;
-        final ObjectMetaData metaData;
-        private XSLFObjectOutputStream(final PackagePart objectPart, final ObjectMetaData metaData) {
-            super(100000);
-            this.objectPart = objectPart;
-            this.metaData = metaData;
-        }
-
-        public void close() throws IOException {
-            objectPart.clear();
-            try (final OutputStream os = objectPart.getOutputStream()) {
-                final ByteArrayInputStream bis = new ByteArrayInputStream(this.buf, 0, size());
-                final FileMagic fm = FileMagic.valueOf(this.buf);
+    private void addUpdatedData(PackagePart objectPart, ObjectMetaData metaData, ByteArrayOutputStream baos) throws IOException {
+        objectPart.clear();
+        try (InputStream bis = FileMagic.prepareToCheckMagic(baos.toInputStream());
+             final OutputStream os = objectPart.getOutputStream()) {
+            final FileMagic fm = FileMagic.valueOf(bis);
 
-                if (fm == FileMagic.OLE2) {
-                    try (final POIFSFileSystem poifs = new POIFSFileSystem(bis)) {
-                        poifs.getRoot().setStorageClsid(metaData.getClassID());
-                        poifs.writeFilesystem(os);
-                    }
-                } else if (metaData.getOleEntry() == null) {
-                    // OLE Name hasn't been specified, pass the input through
-                    os.write(this.buf, 0, size());
-                } else {
-                    try (final POIFSFileSystem poifs = new POIFSFileSystem()) {
-                        final ClassID clsId = metaData.getClassID();
-                        if (clsId != null) {
-                            poifs.getRoot().setStorageClsid(clsId);
-                        }
-                        poifs.createDocument(bis, metaData.getOleEntry());
-
-                        Ole10Native.createOleMarkerEntry(poifs);
-
-                        poifs.writeFilesystem(os);
+            if (fm == FileMagic.OLE2) {
+                try (final POIFSFileSystem poifs = new POIFSFileSystem(bis)) {
+                    poifs.getRoot().setStorageClsid(metaData.getClassID());
+                    poifs.writeFilesystem(os);
+                }
+            } else if (metaData.getOleEntry() == null) {
+                // OLE Name hasn't been specified, pass the input through
+                baos.writeTo(os);
+            } else {
+                try (final POIFSFileSystem poifs = new POIFSFileSystem()) {
+                    final ClassID clsId = metaData.getClassID();
+                    if (clsId != null) {
+                        poifs.getRoot().setStorageClsid(clsId);
                     }
+                    poifs.createDocument(bis, metaData.getOleEntry());
+                    Ole10Native.createOleMarkerEntry(poifs);
+                    poifs.writeFilesystem(os);
                 }
             }
         }
     }
 
-
     /**
-     *
-     *
      * @param shapeId 1-based shapeId
      * @param picRel relationship to the picture data in the ooxml package
-     * @return
      */
     static CTGraphicalObjectFrame prototype(int shapeId, String picRel){
         CTGraphicalObjectFrame frame = CTGraphicalObjectFrame.Factory.newInstance();
diff --git a/poi-ooxml/src/main/java/org/apache/poi/xslf/usermodel/XSLFPictureShape.java b/poi-ooxml/src/main/java/org/apache/poi/xslf/usermodel/XSLFPictureShape.java
index 9c4fc5902e..21462607d9 100644
--- a/poi-ooxml/src/main/java/org/apache/poi/xslf/usermodel/XSLFPictureShape.java
+++ b/poi-ooxml/src/main/java/org/apache/poi/xslf/usermodel/XSLFPictureShape.java
@@ -25,8 +25,6 @@ import java.awt.Insets;
 import java.awt.geom.Dimension2D;
 import java.awt.geom.Rectangle2D;
 import java.awt.image.BufferedImage;
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.net.URI;
@@ -35,6 +33,7 @@ import javax.imageio.ImageIO;
 import javax.xml.namespace.QName;
 import javax.xml.stream.XMLStreamReader;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.poi.ooxml.util.POIXMLUnits;
@@ -127,6 +126,7 @@ public class XSLFPictureShape extends XSLFSimpleShape
      * Return the data on the (internal) picture.
      * For an external linked picture, will return null
      */
+    @Override
     public XSLFPictureData getPictureData() {
         if(_data == null){
             String blipId = getBlipId();
@@ -320,16 +320,16 @@ public class XSLFPictureShape extends XSLFSimpleShape
             : new Rectangle2D.Double(0,0, Units.pixelToPoints((int)dim.getWidth()), Units.pixelToPoints((int)dim.getHeight()));
 
         PictureType pt = (previewType != null) ? previewType : PictureType.PNG;
-        if (pt != PictureType.JPEG || pt != PictureType.GIF || pt != PictureType.PNG) {
+        if (pt != PictureType.JPEG && pt != PictureType.GIF && pt != PictureType.PNG) {
             pt = PictureType.PNG;
         }
 
         BufferedImage thmBI = renderer.getImage(dim);
-        ByteArrayOutputStream bos = new ByteArrayOutputStream(100000);
+        UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream(100000);
         // use extension instead of enum name, because of "jpeg"
         ImageIO.write(thmBI, pt.extension.substring(1), bos);
 
-        XSLFPictureData pngPic = sheet.getSlideShow().addPicture(new ByteArrayInputStream(bos.toByteArray()), pt);
+        XSLFPictureData pngPic = sheet.getSlideShow().addPicture(bos.toInputStream(), pt);
 
         XSLFPictureShape shape = sheet.createPicture(pngPic);
         shape.setAnchor(anc);
@@ -375,7 +375,6 @@ public class XSLFPictureShape extends XSLFSimpleShape
         if(blip.isSetExtLst()) {
             // TODO: check for SVG copying
             CTOfficeArtExtensionList extLst = blip.getExtLst();
-            //noinspection deprecation
             for(CTOfficeArtExtension ext : extLst.getExtArray()){
                 String xpath = "declare namespace a14='"+ MS_DML_NS +"' $this//a14:imgProps/a14:imgLayer";
                 XmlObject[] obj = ext.selectPath(xpath);
diff --git a/poi-ooxml/src/main/java/org/apache/poi/xslf/util/DummyFormat.java b/poi-ooxml/src/main/java/org/apache/poi/xslf/util/DummyFormat.java
index f3dfe26d72..c1cf538c8f 100644
--- a/poi-ooxml/src/main/java/org/apache/poi/xslf/util/DummyFormat.java
+++ b/poi-ooxml/src/main/java/org/apache/poi/xslf/util/DummyFormat.java
@@ -18,7 +18,6 @@
 package org.apache.poi.xslf.util;
 
 import java.awt.Graphics2D;
-import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.FileOutputStream;
 import java.io.IOException;
@@ -26,14 +25,16 @@ import java.io.PrintStream;
 import java.io.UnsupportedEncodingException;
 import java.nio.charset.StandardCharsets;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
+
 public class DummyFormat implements OutputFormat {
 
-    private final ByteArrayOutputStream bos;
+    private final UnsynchronizedByteArrayOutputStream bos;
     private final DummyGraphics2d dummy2d;
 
     public DummyFormat() {
         try {
-            bos = new ByteArrayOutputStream();
+            bos = new UnsynchronizedByteArrayOutputStream();
             dummy2d = new DummyGraphics2d(new PrintStream(bos, true, StandardCharsets.UTF_8.name()));
         } catch (UnsupportedEncodingException e) {
             throw new RuntimeException(e);
@@ -41,7 +42,7 @@ public class DummyFormat implements OutputFormat {
     }
 
     @Override
-    public Graphics2D addSlide(double width, double height) throws IOException {
+    public Graphics2D addSlide(double width, double height) {
         bos.reset();
         return dummy2d;
     }
@@ -55,7 +56,7 @@ public class DummyFormat implements OutputFormat {
     }
 
     @Override
-    public void writeDocument(MFProxy proxy, File outFile) throws IOException {
+    public void writeDocument(MFProxy proxy, File outFile) {
 
     }
 
diff --git a/poi-ooxml/src/main/java/org/apache/poi/xslf/util/PPTX2PNG.java b/poi-ooxml/src/main/java/org/apache/poi/xslf/util/PPTX2PNG.java
index 27f053dc85..81fe1f85cc 100644
--- a/poi-ooxml/src/main/java/org/apache/poi/xslf/util/PPTX2PNG.java
+++ b/poi-ooxml/src/main/java/org/apache/poi/xslf/util/PPTX2PNG.java
@@ -121,6 +121,7 @@ public final class PPTX2PNG {
     private PPTX2PNG() {
     }
 
+    @SuppressWarnings("AssignmentToForLoopParameter")
     private boolean parseCommandLine(String[] args) {
         if (args.length == 0) {
             usage(null);
@@ -403,6 +404,7 @@ public final class PPTX2PNG {
         }
         GenericRecord gr = proxy.getRoot();
         try (GenericRecordJsonWriter fw = new GenericRecordJsonWriter(dumpfile) {
+            @Override
             protected boolean printBytes(String name, Object o) {
                 return false;
             }
diff --git a/poi-ooxml/src/main/java/org/apache/poi/xssf/usermodel/XSSFChartSheet.java b/poi-ooxml/src/main/java/org/apache/poi/xssf/usermodel/XSSFChartSheet.java
index 4cf1ec13a0..6aa3c9f579 100644
--- a/poi-ooxml/src/main/java/org/apache/poi/xssf/usermodel/XSSFChartSheet.java
+++ b/poi-ooxml/src/main/java/org/apache/poi/xssf/usermodel/XSSFChartSheet.java
@@ -20,13 +20,13 @@ package org.apache.poi.xssf.usermodel;
 import static org.apache.poi.ooxml.POIXMLTypeLoader.DEFAULT_XML_OPTIONS;
 
 import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
 
 import javax.xml.namespace.QName;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.ooxml.POIXMLException;
 import org.apache.poi.openxml4j.opc.PackagePart;
 import org.apache.xmlbeans.XmlException;
@@ -95,7 +95,7 @@ public class XSSFChartSheet extends XSSFSheet  {
     }
 
     private static byte[] blankWorksheet(){
-        ByteArrayOutputStream out = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream out = new UnsynchronizedByteArrayOutputStream();
         try {
             new XSSFSheet().write(out);
         } catch (IOException e){
diff --git a/poi-ooxml/src/main/java/org/apache/poi/xssf/usermodel/XSSFObjectData.java b/poi-ooxml/src/main/java/org/apache/poi/xssf/usermodel/XSSFObjectData.java
index 16d04085f2..7001c88b5c 100644
--- a/poi-ooxml/src/main/java/org/apache/poi/xssf/usermodel/XSSFObjectData.java
+++ b/poi-ooxml/src/main/java/org/apache/poi/xssf/usermodel/XSSFObjectData.java
@@ -17,7 +17,6 @@
 
 package org.apache.poi.xssf.usermodel;
 
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 
@@ -68,9 +67,6 @@ public class XSSFObjectData extends XSSFSimpleShape implements ObjectData {
     /**
      * Prototype with the default structure of a new auto-shape.
      */
-    /**
-     * Prototype with the default structure of a new auto-shape.
-     */
     protected static CTShape prototype() {
         final String drawNS = "http://schemas.microsoft.com/office/drawing/2010/main";
 
@@ -92,7 +88,7 @@ public class XSSFObjectData extends XSSFSimpleShape implements ObjectData {
             cur.insertNamespace("a14", drawNS);
             cur.insertAttributeWithValue("spid", "_x0000_s1");
             cur.dispose();
-            
+
             nv.addNewCNvSpPr();
 
             CTShapeProperties sp = shape.addNewSpPr();
@@ -113,16 +109,16 @@ public class XSSFObjectData extends XSSFSimpleShape implements ObjectData {
         return prototype;
     }
 
-    
-    
-    
+
+
+
     @Override
     public String getOLE2ClassName() {
         return getOleObject().getProgId();
     }
 
     /**
-     * @return the CTOleObject associated with the shape 
+     * @return the CTOleObject associated with the shape
      */
     public CTOleObject getOleObject() {
         if (oleObject == null) {
@@ -134,16 +130,14 @@ public class XSSFObjectData extends XSSFSimpleShape implements ObjectData {
         }
         return oleObject;
     }
-    
+
     @Override
     public byte[] getObjectData() throws IOException {
-        InputStream is = getObjectPart().getInputStream();
-        ByteArrayOutputStream bos = new ByteArrayOutputStream();
-        IOUtils.copy(is, bos);
-        is.close();
-        return bos.toByteArray();
+        try (InputStream is = getObjectPart().getInputStream()) {
+            return IOUtils.toByteArray(is);
+        }
     }
-    
+
     /**
      * @return the package part of the object data
      */
@@ -184,7 +178,7 @@ public class XSSFObjectData extends XSSFSimpleShape implements ObjectData {
     public String getFileName() {
         return getObjectPart().getPartName().getName();
     }
-    
+
     protected XSSFSheet getSheet() {
         return (XSSFSheet)getDrawing().getParent();
     }
diff --git a/poi-ooxml/src/main/java/org/apache/poi/xssf/usermodel/XSSFWorkbook.java b/poi-ooxml/src/main/java/org/apache/poi/xssf/usermodel/XSSFWorkbook.java
index 45216a8cdd..5255538ef1 100644
--- a/poi-ooxml/src/main/java/org/apache/poi/xssf/usermodel/XSSFWorkbook.java
+++ b/poi-ooxml/src/main/java/org/apache/poi/xssf/usermodel/XSSFWorkbook.java
@@ -21,8 +21,6 @@ import static org.apache.poi.ooxml.POIXMLTypeLoader.DEFAULT_XML_OPTIONS;
 import static org.apache.poi.xssf.usermodel.helpers.XSSFPasswordHelper.setPassword;
 import static org.apache.poi.xssf.usermodel.helpers.XSSFPasswordHelper.validatePassword;
 
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
@@ -43,6 +41,7 @@ import javax.xml.namespace.QName;
 
 import org.apache.commons.collections4.ListValuedMap;
 import org.apache.commons.collections4.multimap.ArrayListValuedHashMap;
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.poi.hpsf.ClassIDPredefined;
@@ -485,7 +484,7 @@ public class XSSFWorkbook extends POIXMLDocument implements Workbook, Date1904Su
     protected static OPCPackage newPackage(XSSFWorkbookType workbookType) {
         OPCPackage pkg = null;
         try {
-            pkg = OPCPackage.create(new ByteArrayOutputStream());    // NOSONAR - we do not want to close this here
+            pkg = OPCPackage.create(new UnsynchronizedByteArrayOutputStream());    // NOSONAR - we do not want to close this here
             // Main part
             PackagePartName corePartName = PackagingURIHelper.createPartName(XSSFRelation.WORKBOOK.getDefaultFileName());
             // Create main part relationship
@@ -639,9 +638,9 @@ public class XSSFWorkbook extends POIXMLDocument implements Workbook, Date1904Su
         }
 
 
-        try (ByteArrayOutputStream out = new ByteArrayOutputStream()) {
+        try (UnsynchronizedByteArrayOutputStream out = new UnsynchronizedByteArrayOutputStream()) {
             srcSheet.write(out);
-            try (ByteArrayInputStream bis = new ByteArrayInputStream(out.toByteArray())) {
+            try (InputStream bis = out.toInputStream()) {
                 clonedSheet.read(bis);
             }
         } catch (IOException e){
@@ -2346,12 +2345,12 @@ public class XSSFWorkbook extends POIXMLDocument implements Workbook, Date1904Su
 
         Ole10Native ole10 = new Ole10Native(label, fileName, command, oleData);
 
-        try (ByteArrayOutputStream bos = new ByteArrayOutputStream(oleData.length+500)) {
+        try (UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream(oleData.length+500)) {
             ole10.writeOut(bos);
 
             try (POIFSFileSystem poifs = new POIFSFileSystem()) {
                 DirectoryNode root = poifs.getRoot();
-                root.createDocument(Ole10Native.OLE10_NATIVE, new ByteArrayInputStream(bos.toByteArray()));
+                root.createDocument(Ole10Native.OLE10_NATIVE, bos.toInputStream());
                 root.setStorageClsid(ClassIDPredefined.OLE_V1_PACKAGE.getClassID());
 
                 // TODO: generate CombObj stream
diff --git a/poi-ooxml/src/main/java/org/apache/poi/xwpf/usermodel/XWPFDocument.java b/poi-ooxml/src/main/java/org/apache/poi/xwpf/usermodel/XWPFDocument.java
index fcf58ed692..eeed142563 100644
--- a/poi-ooxml/src/main/java/org/apache/poi/xwpf/usermodel/XWPFDocument.java
+++ b/poi-ooxml/src/main/java/org/apache/poi/xwpf/usermodel/XWPFDocument.java
@@ -20,7 +20,6 @@ package org.apache.poi.xwpf.usermodel;
 
 import static org.apache.poi.ooxml.POIXMLTypeLoader.DEFAULT_XML_OPTIONS;
 
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
@@ -36,6 +35,7 @@ import java.util.Map;
 
 import javax.xml.namespace.QName;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.poi.ooxml.POIXMLDocument;
@@ -65,19 +65,37 @@ import org.apache.xmlbeans.XmlException;
 import org.apache.xmlbeans.XmlObject;
 import org.apache.xmlbeans.XmlOptions;
 import org.openxmlformats.schemas.officeDocument.x2006.sharedTypes.STOnOff1;
-import org.openxmlformats.schemas.wordprocessingml.x2006.main.*;
+import org.openxmlformats.schemas.wordprocessingml.x2006.main.CTBody;
+import org.openxmlformats.schemas.wordprocessingml.x2006.main.CTDocument1;
+import org.openxmlformats.schemas.wordprocessingml.x2006.main.CTFtnEdn;
+import org.openxmlformats.schemas.wordprocessingml.x2006.main.CTOnOff;
+import org.openxmlformats.schemas.wordprocessingml.x2006.main.CTP;
+import org.openxmlformats.schemas.wordprocessingml.x2006.main.CTRow;
+import org.openxmlformats.schemas.wordprocessingml.x2006.main.CTSdtBlock;
+import org.openxmlformats.schemas.wordprocessingml.x2006.main.CTSectPr;
+import org.openxmlformats.schemas.wordprocessingml.x2006.main.CTStyles;
+import org.openxmlformats.schemas.wordprocessingml.x2006.main.CTTbl;
+import org.openxmlformats.schemas.wordprocessingml.x2006.main.CTTc;
+import org.openxmlformats.schemas.wordprocessingml.x2006.main.CommentsDocument;
+import org.openxmlformats.schemas.wordprocessingml.x2006.main.DocumentDocument;
+import org.openxmlformats.schemas.wordprocessingml.x2006.main.EndnotesDocument;
+import org.openxmlformats.schemas.wordprocessingml.x2006.main.FootnotesDocument;
+import org.openxmlformats.schemas.wordprocessingml.x2006.main.NumberingDocument;
+import org.openxmlformats.schemas.wordprocessingml.x2006.main.STDocProtect;
+import org.openxmlformats.schemas.wordprocessingml.x2006.main.STHdrFtr;
+import org.openxmlformats.schemas.wordprocessingml.x2006.main.StylesDocument;
 
 /**
- * <p>High(ish) level class for working with .docx files.</p>
+ * High(ish) level class for working with .docx files.
  * <p>
- * <p>This class tries to hide some of the complexity
+ * This class tries to hide some of the complexity
  * of the underlying file format, but as it's not a
  * mature and stable API yet, certain parts of the
  * XML structure come through. You'll therefore almost
  * certainly need to refer to the OOXML specifications
  * from
  * http://www.ecma-international.org/publications/standards/Ecma-376.htm
- * at some point in your use.</p>
+ * at some point in your use.
  */
 @SuppressWarnings("unused")
 public class XWPFDocument extends POIXMLDocument implements Document, IBody {
@@ -103,9 +121,9 @@ public class XWPFDocument extends POIXMLDocument implements Document, IBody {
     /**
      * Keeps track on all id-values used in this document and included parts, like headers, footers, etc.
      */
-    private IdentifierManager drawingIdManager = new IdentifierManager(0L, 4294967295L);
+    private final IdentifierManager drawingIdManager = new IdentifierManager(0L, 4294967295L);
 
-    private FootnoteEndnoteIdManager footnoteIdManager = new FootnoteEndnoteIdManager(this);
+    private final FootnoteEndnoteIdManager footnoteIdManager = new FootnoteEndnoteIdManager(this);
 
     /**
      * Handles the joy of different headers/footers for different pages
@@ -137,7 +155,7 @@ public class XWPFDocument extends POIXMLDocument implements Document, IBody {
     protected static OPCPackage newPackage() {
         OPCPackage pkg = null;
         try {
-            pkg = OPCPackage.create(new ByteArrayOutputStream());    // NOSONAR - we do not want to close this here
+            pkg = OPCPackage.create(new UnsynchronizedByteArrayOutputStream());    // NOSONAR - we do not want to close this here
             // Main part
             PackagePartName corePartName = PackagingURIHelper.createPartName(XWPFRelation.DOCUMENT.getDefaultFileName());
             // Create main part relationship
@@ -306,8 +324,6 @@ public class XWPFDocument extends POIXMLDocument implements Document, IBody {
 
     /**
      * returns an Iterator with paragraphs and tables
-     *
-     * @see IBody#getBodyElements()
      */
     @Override
     public List<IBodyElement> getBodyElements() {
@@ -318,17 +334,11 @@ public class XWPFDocument extends POIXMLDocument implements Document, IBody {
         return bodyElements.iterator();
     }
 
-    /**
-     * @see IBody#getParagraphs()
-     */
     @Override
     public List<XWPFParagraph> getParagraphs() {
         return Collections.unmodifiableList(paragraphs);
     }
 
-    /**
-     * @see IBody#getTables()
-     */
     @Override
     public List<XWPFTable> getTables() {
         return Collections.unmodifiableList(tables);
@@ -341,9 +351,6 @@ public class XWPFDocument extends POIXMLDocument implements Document, IBody {
         return Collections.unmodifiableList(charts);
     }
 
-    /**
-     * @see IBody#getTableArray(int)
-     */
     @Override
     public XWPFTable getTableArray(int pos) {
         if (pos >= 0 && pos < tables.size()) {
@@ -755,8 +762,6 @@ public class XWPFDocument extends POIXMLDocument implements Document, IBody {
 
     /**
      * verifies that cursor is on the right position
-     *
-     * @param cursor
      */
     private boolean isCursorInBody(XmlCursor cursor) {
         XmlCursor verify = cursor.newCursor();
@@ -818,9 +823,6 @@ public class XWPFDocument extends POIXMLDocument implements Document, IBody {
 
     /**
      * Gets the index of the relation we're trying to create
-     *
-     * @param relation
-     * @return i
      */
     private int getRelationIndex(XWPFRelation relation) {
         int i = 1;
@@ -843,11 +845,11 @@ public class XWPFDocument extends POIXMLDocument implements Document, IBody {
         paragraphs.add(p);
         return p;
     }
-    
-    
+
+
     /**
      * Creates an empty comments for the document if one does not already exist
-     * 
+     *
      * @return comments
      */
     public XWPFComments createComments() {
@@ -953,7 +955,6 @@ public class XWPFDocument extends POIXMLDocument implements Document, IBody {
     /**
      * remove a BodyElement from bodyElements array list
      *
-     * @param pos
      * @return true if removing was successfully, else return false
      */
     public boolean removeBodyElement(int pos) {
@@ -977,9 +978,6 @@ public class XWPFDocument extends POIXMLDocument implements Document, IBody {
 
     /**
      * copies content of a paragraph to a existing paragraph in the list paragraphs at position pos
-     *
-     * @param paragraph
-     * @param pos
      */
     public void setParagraph(XWPFParagraph paragraph, int pos) {
         paragraphs.set(pos, paragraph);
@@ -1012,10 +1010,6 @@ public class XWPFDocument extends POIXMLDocument implements Document, IBody {
 
     /**
      * Create an empty table with a number of rows and cols specified
-     *
-     * @param rows
-     * @param cols
-     * @return table
      */
     public XWPFTable createTable(int rows, int cols) {
         XWPFTable table = new XWPFTable(ctDocument.getBody().addNewTbl(), this, rows, cols);
@@ -1045,9 +1039,6 @@ public class XWPFDocument extends POIXMLDocument implements Document, IBody {
 
     /**
      * Replace content of table in array tables at position pos with a
-     *
-     * @param pos
-     * @param table
      */
     public void setTable(int pos, XWPFTable table) {
         tables.set(pos, table);
@@ -1289,7 +1280,6 @@ public class XWPFDocument extends POIXMLDocument implements Document, IBody {
     /**
      * Validates the existing password
      *
-     * @param password
      * @return true, only if password was set and equals, false otherwise
      */
     public boolean validateProtectionPassword(String password) {
@@ -1324,7 +1314,7 @@ public class XWPFDocument extends POIXMLDocument implements Document, IBody {
     /**
      * Check if revision tracking is turned on.
      *
-     * @return <code>true</code> if revision tracking is turned on
+     * @return {@code true} if revision tracking is turned on
      */
     public boolean isTrackRevisions() {
         return settings.isTrackRevisions();
@@ -1333,7 +1323,7 @@ public class XWPFDocument extends POIXMLDocument implements Document, IBody {
     /**
      * Enable or disable revision tracking.
      *
-     * @param enable <code>true</code> to turn on revision tracking, <code>false</code> to turn off revision tracking
+     * @param enable {@code true} to turn on revision tracking, {@code false} to turn off revision tracking
      */
     public void setTrackRevisions(boolean enable) {
         settings.setTrackRevisions(enable);
@@ -1394,9 +1384,6 @@ public class XWPFDocument extends POIXMLDocument implements Document, IBody {
 
     /**
      * inserts an existing XWPFTable to the arrays bodyElements and tables
-     *
-     * @param pos
-     * @param table
      */
     @Override
     public void insertTable(int pos, XWPFTable table) {
@@ -1506,7 +1493,6 @@ public class XWPFDocument extends POIXMLDocument implements Document, IBody {
     /**
      * get the next free ImageNumber
      *
-     * @param format
      * @return the next free ImageNumber
      * @throws InvalidFormatException If the format of the picture is not known.
      */
@@ -1525,7 +1511,6 @@ public class XWPFDocument extends POIXMLDocument implements Document, IBody {
     /**
      * returns the PictureData by blipID
      *
-     * @param blipID
      * @return XWPFPictureData of a specificID
      */
     public XWPFPictureData getPictureDataByID(String blipID) {
@@ -1567,9 +1552,7 @@ public class XWPFDocument extends POIXMLDocument implements Document, IBody {
     /**
      * get a table by its CTTbl-Object
      *
-     * @param ctTbl
      * @return a table by its CTTbl-Object or null
-     * @see IBody#getTable(CTTbl)
      */
     @Override
     public XWPFTable getTable(CTTbl ctTbl) {
@@ -1591,8 +1574,6 @@ public class XWPFDocument extends POIXMLDocument implements Document, IBody {
 
     /**
      * Returns the paragraph that of position pos
-     *
-     * @see IBody#getParagraphArray(int)
      */
     @Override
     public XWPFParagraph getParagraphArray(int pos) {
@@ -1606,8 +1587,6 @@ public class XWPFDocument extends POIXMLDocument implements Document, IBody {
      * returns the Part, to which the body belongs, which you need for adding relationship to other parts
      * Actually it is needed of the class XWPFTableCell. Because you have to know to which part the tableCell
      * belongs.
-     *
-     * @see IBody#getPart()
      */
     @Override
     public POIXMLDocumentPart getPart() {
@@ -1618,8 +1597,6 @@ public class XWPFDocument extends POIXMLDocument implements Document, IBody {
     /**
      * get the PartType of the body, for example
      * DOCUMENT, HEADER, FOOTER, FOOTNOTE,
-     *
-     * @see IBody#getPartType()
      */
     @Override
     public BodyType getPartType() {
@@ -1628,8 +1605,6 @@ public class XWPFDocument extends POIXMLDocument implements Document, IBody {
 
     /**
      * get the TableCell which belongs to the TableCell
-     *
-     * @param cell
      */
     @Override
     public XWPFTableCell getTableCell(CTTc cell) {
@@ -1668,8 +1643,6 @@ public class XWPFDocument extends POIXMLDocument implements Document, IBody {
      * no need to read MS-Word file and modify charts
      *
      * @return This method return object of XWPFChart Object with default height and width
-     * @throws InvalidFormatException
-     * @throws IOException
      * @since POI 4.0.0
      */
     public XWPFChart createChart() throws InvalidFormatException, IOException {
@@ -1683,8 +1656,6 @@ public class XWPFDocument extends POIXMLDocument implements Document, IBody {
      * @param width  width of chart in document
      * @param height height of chart in document
      * @return This method return object of XWPFChart
-     * @throws InvalidFormatException
-     * @throws IOException
      * @since POI 4.0.0
      */
     public XWPFChart createChart(int width, int height) throws InvalidFormatException, IOException {
@@ -1697,8 +1668,6 @@ public class XWPFDocument extends POIXMLDocument implements Document, IBody {
      * @param width in EMU.
      * @param height in EMU.
      * @return the new chart.
-     * @throws InvalidFormatException
-     * @throws IOException
      * @since POI 4.1.2
      */
     public XWPFChart createChart(XWPFRun run, int width, int height) throws InvalidFormatException, IOException {
@@ -1729,8 +1698,7 @@ public class XWPFDocument extends POIXMLDocument implements Document, IBody {
     public XWPFFootnote createFootnote() {
         XWPFFootnotes footnotes = this.createFootnotes();
 
-        XWPFFootnote footnote = footnotes.createFootnote();
-        return footnote;
+        return footnotes.createFootnote();
     }
 
     /**
@@ -1757,8 +1725,7 @@ public class XWPFDocument extends POIXMLDocument implements Document, IBody {
     public XWPFEndnote createEndnote() {
         XWPFEndnotes endnotes = this.createEndnotes();
 
-        XWPFEndnote endnote = endnotes.createEndnote();
-        return endnote;
+        return endnotes.createEndnote();
 
     }
 
diff --git a/poi-ooxml/src/test/java/org/apache/poi/ooxml/TestPOIXMLDocument.java b/poi-ooxml/src/test/java/org/apache/poi/ooxml/TestPOIXMLDocument.java
index 2104a418a8..ca4d10a135 100644
--- a/poi-ooxml/src/test/java/org/apache/poi/ooxml/TestPOIXMLDocument.java
+++ b/poi-ooxml/src/test/java/org/apache/poi/ooxml/TestPOIXMLDocument.java
@@ -17,6 +17,7 @@
 
 package org.apache.poi.ooxml;
 
+import static org.apache.commons.io.output.NullOutputStream.NULL_OUTPUT_STREAM;
 import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
@@ -25,7 +26,6 @@ import static org.junit.jupiter.api.Assertions.assertNull;
 import static org.junit.jupiter.api.Assertions.assertSame;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
-import static org.junit.jupiter.api.Assertions.fail;
 
 import java.io.ByteArrayInputStream;
 import java.io.File;
@@ -46,7 +46,6 @@ import org.apache.poi.openxml4j.opc.OPCPackage;
 import org.apache.poi.openxml4j.opc.PackagePart;
 import org.apache.poi.openxml4j.opc.PackageRelationshipTypes;
 import org.apache.poi.util.IOUtils;
-import org.apache.poi.util.NullOutputStream;
 import org.apache.poi.util.TempFile;
 import org.apache.poi.xslf.usermodel.XMLSlideShow;
 import org.apache.poi.xssf.usermodel.XSSFRelation;
@@ -142,7 +141,7 @@ public final class TestPOIXMLDocument {
 
                 // Should not be able to write a document that has been closed
                 doc.close();
-                IOException e2 = assertThrows(IOException.class, () -> doc.write(new NullOutputStream()),
+                IOException e2 = assertThrows(IOException.class, () -> doc.write(NULL_OUTPUT_STREAM),
                     "Should not be able to write a document that has been closed.");
                 assertEquals("Cannot write data, document seems to have been closed already", e2.getMessage());
 
@@ -292,7 +291,7 @@ public final class TestPOIXMLDocument {
             XMLSlideShow ppt = new XMLSlideShow(is)) {
             POIXMLDocumentPart doc = ppt.getSlides().get(12).getRelationById("rId3");
             assertNotNull(doc);
-            assertEquals(POIXMLDocumentPart.class, doc.getClass());
+            assertSame(POIXMLDocumentPart.class, doc.getClass());
         }
     }
 
@@ -334,6 +333,7 @@ public final class TestPOIXMLDocument {
     private static class UncaughtHandler implements UncaughtExceptionHandler {
         Throwable e;
 
+        @Override
         public synchronized void uncaughtException(Thread t, Throwable e) {
             this.e = e;
         }
diff --git a/poi-ooxml/src/test/java/org/apache/poi/openxml4j/OpenXML4JTestDataSamples.java b/poi-ooxml/src/test/java/org/apache/poi/openxml4j/OpenXML4JTestDataSamples.java
index 1c6b942a58..4068a8e80d 100644
--- a/poi-ooxml/src/test/java/org/apache/poi/openxml4j/OpenXML4JTestDataSamples.java
+++ b/poi-ooxml/src/test/java/org/apache/poi/openxml4j/OpenXML4JTestDataSamples.java
@@ -25,7 +25,7 @@ import java.io.InputStream;
 import java.io.IOException;
 
 /**
- * Centralises logic for finding/opening sample files for ooxml4j unit tests 
+ * Centralises logic for finding/opening sample files for ooxml4j unit tests
  */
 public final class OpenXML4JTestDataSamples {
     private static final POIDataSamples _samples = POIDataSamples.getOpenXML4JInstance();
@@ -40,19 +40,13 @@ public final class OpenXML4JTestDataSamples {
 	public static String getSampleFileName(String sampleFileName) {
 		return getSampleFile(sampleFileName).getAbsolutePath();
 	}
-	
+
 	public static File getSampleFile(String sampleFileName) {
 		return _samples.getFile(sampleFileName);
 	}
-	
-	public static File getOutputFile(String outputFileName) throws IOException {
-        String suffix = outputFileName.substring(outputFileName.lastIndexOf('.'));
-        return TempFile.createTempFile(outputFileName, suffix);
-	}
 
-
-	public static InputStream openComplianceSampleStream(String sampleFileName) {
-        return _samples.openResourceAsStream(sampleFileName);
+	public static File getOutputFile(String outputFileName) throws IOException {
+		int idx = outputFileName.lastIndexOf('.');
+        return TempFile.createTempFile(outputFileName.substring(0,idx), outputFileName.substring(idx));
 	}
-
 }
diff --git a/poi-ooxml/src/test/java/org/apache/poi/openxml4j/opc/TestPackage.java b/poi-ooxml/src/test/java/org/apache/poi/openxml4j/opc/TestPackage.java
index 9f297f66c6..9e9997d38f 100644
--- a/poi-ooxml/src/test/java/org/apache/poi/openxml4j/opc/TestPackage.java
+++ b/poi-ooxml/src/test/java/org/apache/poi/openxml4j/opc/TestPackage.java
@@ -33,7 +33,6 @@ import static org.junit.jupiter.api.Assertions.fail;
 
 import java.io.BufferedInputStream;
 import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.FileOutputStream;
@@ -58,6 +57,8 @@ import com.google.common.io.Files;
 import org.apache.commons.compress.archivers.zip.ZipArchiveEntry;
 import org.apache.commons.compress.archivers.zip.ZipArchiveOutputStream;
 import org.apache.commons.compress.archivers.zip.ZipFile;
+import org.apache.commons.io.output.CountingOutputStream;
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.poi.EncryptedDocumentException;
@@ -217,7 +218,7 @@ public final class TestPackage {
 	 */
     @Test
 	void createPackageWithCoreDocument() throws IOException, InvalidFormatException, URISyntaxException, SAXException {
-		ByteArrayOutputStream baos = new ByteArrayOutputStream();
+		UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
 		try (OPCPackage pkg = OPCPackage.create(baos)) {
 
 			// Add a core document
@@ -675,7 +676,7 @@ public final class TestPackage {
     @Test
     void zipBombCreateAndHandle()
     throws IOException, EncryptedDocumentException {
-		ByteArrayOutputStream bos = new ByteArrayOutputStream(2500000);
+		UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream(2500000);
 
         try (ZipFile zipFile = ZipHelper.openZipFile(getSampleFile("sample.xlsx"));
 			 ZipArchiveOutputStream append = new ZipArchiveOutputStream(bos)) {
@@ -693,21 +694,19 @@ public final class TestPackage {
 				append.putArchiveEntry(eOut);
 				if (!eOut.isDirectory()) {
 					try (InputStream is = zipFile.getInputStream(eIn)) {
-						if (eOut.getName().equals("[Content_Types].xml")) {
-							ByteArrayOutputStream bos2 = new ByteArrayOutputStream();
-							IOUtils.copy(is, bos2);
-							long size = bos2.size() - "</Types>".length();
-							append.write(bos2.toByteArray(), 0, (int) size);
+						if ("[Content_Types].xml".equals(eOut.getName())) {
+							byte[] suffix = "</Types>".getBytes(StandardCharsets.UTF_8);
+							CountingOutputStream cos = new CountingOutputStream(append);
+							IOUtils.copy(is, cos, eOut.getSize() - suffix.length);
+
                             byte[] spam = new byte[0x7FFF];
 							Arrays.fill(spam, (byte) ' ');
 							// 0x7FFF0000 is the maximum for 32-bit zips, but less still works
-							while (size < 0x7FFF00) {
-								append.write(spam);
-								size += spam.length;
+							while (cos.getByteCount() < 0x7FFF00) {
+								cos.write(spam);
 							}
-							append.write("</Types>".getBytes(StandardCharsets.UTF_8));
-							size += 8;
-							eOut.setSize(size);
+							cos.write(suffix);
+							eOut.setSize(cos.getByteCount());
 						} else {
 							IOUtils.copy(is, append);
 						}
@@ -717,10 +716,7 @@ public final class TestPackage {
 			}
 		}
 
-		IOException ex = assertThrows(
-			IOException.class,
-			() -> WorkbookFactory.create(new ByteArrayInputStream(bos.toByteArray()))
-		);
+		IOException ex = assertThrows(IOException.class, () -> WorkbookFactory.create(bos.toInputStream()));
         assertTrue(ex.getMessage().contains("Zip bomb detected!"));
     }
 
diff --git a/poi-ooxml/src/test/java/org/apache/poi/openxml4j/opc/TestPackageCoreProperties.java b/poi-ooxml/src/test/java/org/apache/poi/openxml4j/opc/TestPackageCoreProperties.java
index 317d1009a0..6dbfcf0dc9 100644
--- a/poi-ooxml/src/test/java/org/apache/poi/openxml4j/opc/TestPackageCoreProperties.java
+++ b/poi-ooxml/src/test/java/org/apache/poi/openxml4j/opc/TestPackageCoreProperties.java
@@ -17,8 +17,17 @@
 
 package org.apache.poi.openxml4j.opc;
 
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
+import static org.apache.poi.openxml4j.OpenXML4JTestDataSamples.getSampleFileName;
+import static org.apache.poi.openxml4j.OpenXML4JTestDataSamples.openSampleStream;
+import static org.apache.poi.openxml4j.opc.PackageRelationshipTypes.CORE_DOCUMENT;
+import static org.apache.poi.openxml4j.opc.PackageRelationshipTypes.CORE_PROPERTIES;
+import static org.apache.poi.openxml4j.opc.PackageRelationshipTypes.EXTENDED_PROPERTIES;
+import static org.apache.poi.openxml4j.opc.TestContentType.isOldXercesActive;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
 import java.io.File;
 import java.io.InputStream;
 import java.text.ParsePosition;
@@ -27,6 +36,7 @@ import java.util.Date;
 import java.util.Locale;
 import java.util.Optional;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.POIDataSamples;
 import org.apache.poi.openxml4j.OpenXML4JTestDataSamples;
 import org.apache.poi.openxml4j.exceptions.InvalidFormatException;
@@ -36,9 +46,6 @@ import org.apache.poi.xssf.usermodel.XSSFWorkbook;
 import org.junit.jupiter.api.Test;
 import org.openxmlformats.schemas.officeDocument.x2006.customProperties.CTProperty;
 
-import static org.apache.poi.openxml4j.opc.TestContentType.isOldXercesActive;
-import static org.junit.jupiter.api.Assertions.*;
-
 public final class TestPackageCoreProperties {
 	/**
 	 * Test package core properties getters.
@@ -47,7 +54,7 @@ public final class TestPackageCoreProperties {
 	void testGetProperties() throws Exception {
 		// Open the package
 		@SuppressWarnings("resource")
-        OPCPackage p = OPCPackage.open(OpenXML4JTestDataSamples.openSampleStream("TestPackageCoreProperiesGetters.docx"));
+        OPCPackage p = OPCPackage.open(openSampleStream("TestPackageCoreProperiesGetters.docx"));
 		compareProperties(p);
 		p.revert();
 	}
@@ -57,7 +64,7 @@ public final class TestPackageCoreProperties {
 	 */
     @Test
     void testSetProperties() throws Exception {
-		String inputPath = OpenXML4JTestDataSamples.getSampleFileName("TestPackageCoreProperiesSetters.docx");
+		String inputPath = getSampleFileName("TestPackageCoreProperiesSetters.docx");
 
 		File outputFile = OpenXML4JTestDataSamples.getOutputFile("TestPackageCoreProperiesSettersOUTPUT.docx");
 
@@ -75,28 +82,28 @@ public final class TestPackageCoreProperties {
 
         //test various date formats
         props.setCreatedProperty("2007-05-12T08:00:00Z");
-        assertEquals(dateToInsert, props.getCreatedProperty().get());
+        assertEquals(dateToInsert, props.getCreatedProperty().orElse(null));
 
         props.setCreatedProperty("2007-05-12T08:00:00"); //no Z, assume Z
-        assertEquals(dateToInsert, props.getCreatedProperty().get());
+        assertEquals(dateToInsert, props.getCreatedProperty().orElse(null));
 
         props.setCreatedProperty("2007-05-12T08:00:00.123Z");//millis
-        assertEquals(msdf.parse("2007-05-12T08:00:00.123Z"), props.getCreatedProperty().get());
+        assertEquals(msdf.parse("2007-05-12T08:00:00.123Z"), props.getCreatedProperty().orElse(null));
 
         props.setCreatedProperty("2007-05-12T10:00:00+0200");
-        assertEquals(dateToInsert, props.getCreatedProperty().get());
+        assertEquals(dateToInsert, props.getCreatedProperty().orElse(null));
 
         props.setCreatedProperty("2007-05-12T10:00:00+02:00");//colon in tz
-        assertEquals(dateToInsert, props.getCreatedProperty().get());
+        assertEquals(dateToInsert, props.getCreatedProperty().orElse(null));
 
         props.setCreatedProperty("2007-05-12T06:00:00-0200");
-        assertEquals(dateToInsert, props.getCreatedProperty().get());
+        assertEquals(dateToInsert, props.getCreatedProperty().orElse(null));
 
         props.setCreatedProperty("2015-07-27");
-        assertEquals(msdf.parse("2015-07-27T00:00:00.000Z"), props.getCreatedProperty().get());
+        assertEquals(msdf.parse("2015-07-27T00:00:00.000Z"), props.getCreatedProperty().orElse(null));
 
         props.setCreatedProperty("2007-05-12T10:00:00.123+0200");
-        assertEquals(msdf.parse("2007-05-12T08:00:00.123Z"), props.getCreatedProperty().get());
+        assertEquals(msdf.parse("2007-05-12T08:00:00.123Z"), props.getCreatedProperty().orElse(null));
 
         props.setCategoryProperty("MyCategory");
 		props.setContentStatusProperty("MyContentStatus");
@@ -122,7 +129,7 @@ public final class TestPackageCoreProperties {
         OPCPackage p2 = OPCPackage.open(outputFile.getAbsolutePath(), PackageAccess.READ);
 	    compareProperties(p2);
 	    p2.revert();
-		outputFile.delete();
+		assertTrue(outputFile.delete());
 	}
 
 	private void compareProperties(OPCPackage p) throws InvalidFormatException {
@@ -132,22 +139,22 @@ public final class TestPackageCoreProperties {
 
 		// Gets the core properties
 		PackageProperties props = p.getPackageProperties();
-		assertEquals("MyCategory", props.getCategoryProperty().get());
-		assertEquals("MyContentStatus", props.getContentStatusProperty().get());
-		assertEquals("MyContentType", props.getContentTypeProperty().get());
-		assertEquals(expectedDate, props.getCreatedProperty().get());
-		assertEquals("MyCreator", props.getCreatorProperty().get());
-		assertEquals("MyDescription", props.getDescriptionProperty().get());
-		assertEquals("MyIdentifier", props.getIdentifierProperty().get());
-		assertEquals("MyKeywords", props.getKeywordsProperty().get());
-		assertEquals("MyLanguage", props.getLanguageProperty().get());
-		assertEquals("Julien Chable", props.getLastModifiedByProperty().get());
-		assertEquals(expectedDate, props.getLastPrintedProperty().get());
-		assertEquals(expectedDate, props.getModifiedProperty().get());
-		assertEquals("2", props.getRevisionProperty().get());
-		assertEquals("MySubject", props.getSubjectProperty().get());
-		assertEquals("MyTitle", props.getTitleProperty().get());
-		assertEquals("2", props.getVersionProperty().get());
+		assertEquals("MyCategory", props.getCategoryProperty().orElse(null));
+		assertEquals("MyContentStatus", props.getContentStatusProperty().orElse(null));
+		assertEquals("MyContentType", props.getContentTypeProperty().orElse(null));
+		assertEquals(expectedDate, props.getCreatedProperty().orElse(null));
+		assertEquals("MyCreator", props.getCreatorProperty().orElse(null));
+		assertEquals("MyDescription", props.getDescriptionProperty().orElse(null));
+		assertEquals("MyIdentifier", props.getIdentifierProperty().orElse(null));
+		assertEquals("MyKeywords", props.getKeywordsProperty().orElse(null));
+		assertEquals("MyLanguage", props.getLanguageProperty().orElse(null));
+		assertEquals("Julien Chable", props.getLastModifiedByProperty().orElse(null));
+		assertEquals(expectedDate, props.getLastPrintedProperty().orElse(null));
+		assertEquals(expectedDate, props.getModifiedProperty().orElse(null));
+		assertEquals("2", props.getRevisionProperty().orElse(null));
+		assertEquals("MySubject", props.getSubjectProperty().orElse(null));
+		assertEquals("MyTitle", props.getTitleProperty().orElse(null));
+		assertEquals("2", props.getVersionProperty().orElse(null));
 	}
 
 	@Test
@@ -157,90 +164,92 @@ public final class TestPackageCoreProperties {
         String strDate = "2007-05-12T08:00:00Z";
         Date date = df.parse(strDate);
 
-        OPCPackage pkg = new ZipPackage();
-        PackagePropertiesPart props = (PackagePropertiesPart)pkg.getPackageProperties();
-
-        // created
-        assertEquals("", props.getCreatedPropertyString());
-        assertFalse(props.getCreatedProperty().isPresent());
-        props.setCreatedProperty((String)null);
-        assertEquals("", props.getCreatedPropertyString());
-        assertFalse(props.getCreatedProperty().isPresent());
-        props.setCreatedProperty(Optional.empty());
-        assertEquals("", props.getCreatedPropertyString());
-        assertFalse(props.getCreatedProperty().isPresent());
-        props.setCreatedProperty(Optional.of(date));
-        assertEquals(strDate, props.getCreatedPropertyString());
-        assertEquals(date, props.getCreatedProperty().get());
-        props.setCreatedProperty(strDate);
-        assertEquals(strDate, props.getCreatedPropertyString());
-        assertEquals(date, props.getCreatedProperty().get());
-
-        // lastPrinted
-        assertEquals("", props.getLastPrintedPropertyString());
-        assertFalse(props.getLastPrintedProperty().isPresent());
-        props.setLastPrintedProperty((String)null);
-        assertEquals("", props.getLastPrintedPropertyString());
-        assertFalse(props.getLastPrintedProperty().isPresent());
-        props.setLastPrintedProperty(Optional.empty());
-        assertEquals("", props.getLastPrintedPropertyString());
-        assertFalse(props.getLastPrintedProperty().isPresent());
-        props.setLastPrintedProperty(Optional.of(date));
-        assertEquals(strDate, props.getLastPrintedPropertyString());
-        assertEquals(date, props.getLastPrintedProperty().get());
-        props.setLastPrintedProperty(strDate);
-        assertEquals(strDate, props.getLastPrintedPropertyString());
-        assertEquals(date, props.getLastPrintedProperty().get());
-
-        // modified
-        assertFalse(props.getModifiedProperty().isPresent());
-        props.setModifiedProperty((String)null);
-        assertFalse(props.getModifiedProperty().isPresent());
-        props.setModifiedProperty(Optional.empty());
-        assertFalse(props.getModifiedProperty().isPresent());
-        props.setModifiedProperty(Optional.of(date));
-        assertEquals(strDate, props.getModifiedPropertyString());
-        assertEquals(date, props.getModifiedProperty().get());
-        props.setModifiedProperty(strDate);
-        assertEquals(strDate, props.getModifiedPropertyString());
-        assertEquals(date, props.getModifiedProperty().get());
-
-        // Tidy
-        pkg.close();
+        try (OPCPackage pkg = new ZipPackage()) {
+            PackagePropertiesPart props = (PackagePropertiesPart) pkg.getPackageProperties();
+
+            // created
+            assertEquals("", props.getCreatedPropertyString());
+            assertFalse(props.getCreatedProperty().isPresent());
+            props.setCreatedProperty((String) null);
+            assertEquals("", props.getCreatedPropertyString());
+            assertFalse(props.getCreatedProperty().isPresent());
+            props.setCreatedProperty(Optional.empty());
+            assertEquals("", props.getCreatedPropertyString());
+            assertFalse(props.getCreatedProperty().isPresent());
+            props.setCreatedProperty(Optional.of(date));
+            assertEquals(strDate, props.getCreatedPropertyString());
+            assertEquals(date, props.getCreatedProperty().get());
+            props.setCreatedProperty(strDate);
+            assertEquals(strDate, props.getCreatedPropertyString());
+            assertEquals(date, props.getCreatedProperty().get());
+
+            // lastPrinted
+            assertEquals("", props.getLastPrintedPropertyString());
+            assertFalse(props.getLastPrintedProperty().isPresent());
+            props.setLastPrintedProperty((String) null);
+            assertEquals("", props.getLastPrintedPropertyString());
+            assertFalse(props.getLastPrintedProperty().isPresent());
+            props.setLastPrintedProperty(Optional.empty());
+            assertEquals("", props.getLastPrintedPropertyString());
+            assertFalse(props.getLastPrintedProperty().isPresent());
+            props.setLastPrintedProperty(Optional.of(date));
+            assertEquals(strDate, props.getLastPrintedPropertyString());
+            assertEquals(date, props.getLastPrintedProperty().get());
+            props.setLastPrintedProperty(strDate);
+            assertEquals(strDate, props.getLastPrintedPropertyString());
+            assertEquals(date, props.getLastPrintedProperty().get());
+
+            // modified
+            assertFalse(props.getModifiedProperty().isPresent());
+            props.setModifiedProperty((String) null);
+            assertFalse(props.getModifiedProperty().isPresent());
+            props.setModifiedProperty(Optional.empty());
+            assertFalse(props.getModifiedProperty().isPresent());
+            props.setModifiedProperty(Optional.of(date));
+            assertEquals(strDate, props.getModifiedPropertyString());
+            assertEquals(date, props.getModifiedProperty().get());
+            props.setModifiedProperty(strDate);
+            assertEquals(strDate, props.getModifiedPropertyString());
+            assertEquals(date, props.getModifiedProperty().get());
+        }
     }
 
 	@Test
 	void testGetPropertiesLO() throws Exception {
+        UnsynchronizedByteArrayOutputStream out = new UnsynchronizedByteArrayOutputStream();
         // Open the package
-        OPCPackage pkg1 = OPCPackage.open(OpenXML4JTestDataSamples.openSampleStream("51444.xlsx"));
-        PackageProperties props1 = pkg1.getPackageProperties();
-        assertFalse(props1.getTitleProperty().isPresent());
-        props1.setTitleProperty("Bug 51444 fixed");
-        ByteArrayOutputStream out = new ByteArrayOutputStream();
-        pkg1.save(out);
-        out.close();
-        pkg1.close();
-
-        OPCPackage pkg2 = OPCPackage.open(new ByteArrayInputStream(out.toByteArray()));
-        PackageProperties props2 = pkg2.getPackageProperties();
-        props2.setTitleProperty("Bug 51444 fixed");
-        pkg2.close();
+        try (OPCPackage pkg1 = OPCPackage.open(openSampleStream("51444.xlsx"))) {
+            PackageProperties props1 = pkg1.getPackageProperties();
+            assertFalse(props1.getTitleProperty().isPresent());
+            props1.setTitleProperty("Bug 51444 fixed");
+            pkg1.save(out);
+        }
+
+        try (OPCPackage pkg2 = OPCPackage.open(out.toInputStream())) {
+            PackageProperties props2 = pkg2.getPackageProperties();
+            props2.setTitleProperty("Bug 51444 fixed");
+        }
     }
 
 	@Test
 	void testEntitiesInCoreProps_56164() throws Exception {
-        try (InputStream is = OpenXML4JTestDataSamples.openSampleStream("CorePropertiesHasEntities.ooxml");
-        OPCPackage p = OPCPackage.open(is)) {
+        try (InputStream is = openSampleStream("CorePropertiesHasEntities.ooxml");
+             OPCPackage p = OPCPackage.open(is)) {
 
             // Should have 3 root relationships
             boolean foundDocRel = false, foundCorePropRel = false, foundExtPropRel = false;
             for (PackageRelationship pr : p.getRelationships()) {
-                if (pr.getRelationshipType().equals(PackageRelationshipTypes.CORE_DOCUMENT))
-                    foundDocRel = true;
-                if (pr.getRelationshipType().equals(PackageRelationshipTypes.CORE_PROPERTIES))
-                    foundCorePropRel = true;
-                if (pr.getRelationshipType().equals(PackageRelationshipTypes.EXTENDED_PROPERTIES))
-                    foundExtPropRel = true;
+                switch (pr.getRelationshipType()) {
+                    case CORE_DOCUMENT:
+                        foundDocRel = true;
+                        break;
+                    case CORE_PROPERTIES:
+                        foundCorePropRel = true;
+                        break;
+                    case EXTENDED_PROPERTIES:
+                        foundExtPropRel = true;
+                        break;
+                }
             }
             assertTrue(foundDocRel, "Core Doc Relationship not found in " + p.getRelationships());
             assertTrue(foundCorePropRel, "Core Props Relationship not found in " + p.getRelationships());
@@ -257,67 +266,68 @@ public final class TestPackageCoreProperties {
 	@Test
 	void testListOfCustomProperties() throws Exception {
         File inp = POIDataSamples.getSpreadSheetInstance().getFile("ExcelWithAttachments.xlsm");
-        OPCPackage pkg = OPCPackage.open(inp, PackageAccess.READ);
-        XSSFWorkbook wb = new XSSFWorkbook(pkg);
+        try (OPCPackage pkg = OPCPackage.open(inp, PackageAccess.READ);
+             XSSFWorkbook wb = new XSSFWorkbook(pkg)) {
 
-        assertNotNull(wb.getProperties());
-        assertNotNull(wb.getProperties().getCustomProperties());
+            assertNotNull(wb.getProperties());
+            assertNotNull(wb.getProperties().getCustomProperties());
 
-        for (CTProperty prop : wb.getProperties().getCustomProperties().getUnderlyingProperties().getPropertyList()) {
-            assertNotNull(prop);
+            for (CTProperty prop : wb.getProperties().getCustomProperties().getUnderlyingProperties().getPropertyList()) {
+                assertNotNull(prop);
+            }
         }
-
-        wb.close();
-        pkg.close();
     }
 
 	@Test
 	void testAlternateCorePropertyTimezones() throws Exception {
-        InputStream is = OpenXML4JTestDataSamples.openSampleStream("OPCCompliance_CoreProperties_AlternateTimezones.docx");
-        OPCPackage pkg = OPCPackage.open(is);
-        PackagePropertiesPart props = (PackagePropertiesPart)pkg.getPackageProperties();
-        is.close();
-
         // We need predictable dates for testing!
         SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'", Locale.ROOT);
         df.setTimeZone(LocaleUtil.TIMEZONE_UTC);
 
-        // Check text properties first
-        assertEquals("Lorem Ipsum", props.getTitleProperty().get());
-        assertEquals("Apache POI", props.getCreatorProperty().get());
-
-        // Created at has a +3 timezone and milliseconds
-        //   2006-10-13T18:06:00.123+03:00
-        // = 2006-10-13T15:06:00.123+00:00
-        assertEquals("2006-10-13T15:06:00Z", props.getCreatedPropertyString());
-        assertEquals("2006-10-13T15:06:00.123Z", df.format(props.getCreatedProperty().get()));
+        UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
+        try (InputStream is = openSampleStream("OPCCompliance_CoreProperties_AlternateTimezones.docx");
+            OPCPackage pkg1 = OPCPackage.open(is)) {
+            PackagePropertiesPart props1 = (PackagePropertiesPart) pkg1.getPackageProperties();
 
-        // Modified at has a -13 timezone but no milliseconds
-        //   2007-06-20T07:59:00-13:00
-        // = 2007-06-20T20:59:00-13:00
-        assertEquals("2007-06-20T20:59:00Z", props.getModifiedPropertyString());
-        assertEquals("2007-06-20T20:59:00.000Z", df.format(props.getModifiedProperty().get()));
+            // Check text properties first
+            assertEquals("Lorem Ipsum", props1.getTitleProperty().orElse(null));
+            assertEquals("Apache POI", props1.getCreatorProperty().orElse(null));
 
+            // Created at has a +3 timezone and milliseconds
+            //   2006-10-13T18:06:00.123+03:00
+            // = 2006-10-13T15:06:00.123+00:00
+            assertEquals("2006-10-13T15:06:00Z", props1.getCreatedPropertyString());
+            assertEquals("2006-10-13T15:06:00.123Z", df.format(props1.getCreatedProperty().orElse(null)));
 
-        // Ensure we can change them with other timezones and still read back OK
-        props.setCreatedProperty("2007-06-20T20:57:00+13:00");
-        props.setModifiedProperty("2007-06-20T20:59:00.123-13:00");
+            // Modified at has a -13 timezone but no milliseconds
+            //   2007-06-20T07:59:00-13:00
+            // = 2007-06-20T20:59:00-13:00
+            assertEquals("2007-06-20T20:59:00Z", props1.getModifiedPropertyString());
+            assertEquals("2007-06-20T20:59:00.000Z", df.format(props1.getModifiedProperty().orElse(null)));
 
-        ByteArrayOutputStream baos = new ByteArrayOutputStream();
-        pkg.save(baos);
-        pkg = OPCPackage.open(new ByteArrayInputStream(baos.toByteArray()));
 
-        // Check text properties first - should be unchanged
-        assertEquals("Lorem Ipsum", props.getTitleProperty().get());
-        assertEquals("Apache POI", props.getCreatorProperty().get());
+            // Ensure we can change them with other timezones and still read back OK
+            props1.setCreatedProperty("2007-06-20T20:57:00+13:00");
+            props1.setModifiedProperty("2007-06-20T20:59:00.123-13:00");
 
-        // Check the updated times
-        //   2007-06-20T20:57:00+13:00
-        // = 2007-06-20T07:57:00Z
-        assertEquals("2007-06-20T07:57:00.000Z", df.format(props.getCreatedProperty().get()));
-
-        //   2007-06-20T20:59:00.123-13:00
-        // = 2007-06-21T09:59:00.123Z
-        assertEquals("2007-06-21T09:59:00.123Z", df.format(props.getModifiedProperty().get()));
+            pkg1.save(baos);
+        }
+        try (OPCPackage pkg2 = OPCPackage.open(baos.toInputStream())) {
+            PackagePropertiesPart props2 = (PackagePropertiesPart) pkg2.getPackageProperties();
+
+            // Check text properties first - should be unchanged
+            assertEquals("Lorem Ipsum", props2.getTitleProperty().orElse(null));
+            assertEquals("Apache POI", props2.getCreatorProperty().orElse(null));
+
+            // Check the updated times
+            //   2007-06-20T20:57:00+13:00
+            // = 2007-06-20T07:57:00Z
+            assertEquals("2007-06-20T07:57:00.000Z", df.format(props2.getCreatedProperty().orElse(null)));
+
+            //   2007-06-20T20:59:00.123-13:00
+            // = 2007-06-21T09:59:00.123Z
+            // CoreProperties are stored as xs:dateTime -> no milliseconds are saved!
+            assertEquals("2007-06-21T09:59:00.000Z", df.format(props2.getModifiedProperty().orElse(null)));
+        }
 	}
 }
diff --git a/poi-ooxml/src/test/java/org/apache/poi/openxml4j/opc/TestRelationships.java b/poi-ooxml/src/test/java/org/apache/poi/openxml4j/opc/TestRelationships.java
index d80c88ae12..d6b81c9a54 100644
--- a/poi-ooxml/src/test/java/org/apache/poi/openxml4j/opc/TestRelationships.java
+++ b/poi-ooxml/src/test/java/org/apache/poi/openxml4j/opc/TestRelationships.java
@@ -24,12 +24,11 @@ import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertNull;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.InputStream;
 import java.net.URI;
 import java.util.regex.Pattern;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.poi.openxml4j.OpenXML4JTestDataSamples;
@@ -198,18 +197,16 @@ class TestRelationships {
 
 
 	    // Write out and re-load
-	    ByteArrayOutputStream baos = new ByteArrayOutputStream();
+	    UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
 	    pkg.save(baos);
 
 	    // use revert to not re-write the input file
         pkg.revert();
 
-        ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
-	    pkg = OPCPackage.open(bais);
+	    pkg = OPCPackage.open(baos.toInputStream());
 
 	    // Check again
-	    sheet = pkg.getPart(
-	    		PackagingURIHelper.createPartName(SHEET_WITH_COMMENTS));
+	    sheet = pkg.getPart(PackagingURIHelper.createPartName(SHEET_WITH_COMMENTS));
 
 	    assertEquals(6, sheet.getRelationshipsByType(HYPERLINK_REL_TYPE).size());
 
@@ -228,7 +225,7 @@ class TestRelationships {
 
     @Test
     void testCreateRelationsFromScratch() throws Exception {
-        ByteArrayOutputStream baos = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
         OPCPackage pkg = OPCPackage.create(baos);
 
         PackagePart partA =
@@ -255,8 +252,7 @@ class TestRelationships {
 
         // Save, and re-load
         pkg.close();
-        ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
-        pkg = OPCPackage.open(bais);
+        pkg = OPCPackage.open(baos.toInputStream());
 
         partA = pkg.getPart(PackagingURIHelper.createPartName("/partA"));
         partB = pkg.getPart(PackagingURIHelper.createPartName("/partB"));
@@ -297,20 +293,17 @@ class TestRelationships {
 
     @Test
     void testTargetWithSpecialChars() throws Exception{
-        OPCPackage pkg;
-
         String filepath = OpenXML4JTestDataSamples.getSampleFileName("50154.xlsx");
-        pkg = OPCPackage.open(filepath);
+        OPCPackage pkg = OPCPackage.open(filepath);
         assert_50154(pkg);
 
-        ByteArrayOutputStream baos = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
         pkg.save(baos);
 
         // use revert to not re-write the input file
         pkg.revert();
 
-        ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
-        pkg = OPCPackage.open(bais);
+        pkg = OPCPackage.open(baos.toInputStream());
 
         assert_50154(pkg);
     }
@@ -359,7 +352,7 @@ class TestRelationships {
 
    @Test
    void testSelfRelations_bug51187() throws Exception {
-    	ByteArrayOutputStream baos = new ByteArrayOutputStream();
+    	UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
         PackageRelationship rel1;
     	try (OPCPackage pkg = OPCPackage.create(baos)) {
 
@@ -374,8 +367,7 @@ class TestRelationships {
             // Save, and re-load
         }
 
-        ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
-    	try (OPCPackage pkg = OPCPackage.open(bais)) {
+    	try (OPCPackage pkg = OPCPackage.open(baos.toInputStream())) {
             PackagePart partA = pkg.getPart(PackagingURIHelper.createPartName("/partA"));
 
 
@@ -406,11 +398,10 @@ class TestRelationships {
             assertEquals("mailto:nobody@nowhere.uk%C2%A0", targetUri.toASCIIString());
             assertEquals("nobody@nowhere.uk\u00A0", targetUri.getSchemeSpecificPart());
 
-            ByteArrayOutputStream out = new ByteArrayOutputStream();
+            UnsynchronizedByteArrayOutputStream out = new UnsynchronizedByteArrayOutputStream();
             pkg1.save(out);
-            out.close();
 
-            try (OPCPackage pkg2 = OPCPackage.open(new ByteArrayInputStream(out.toByteArray()))) {
+            try (OPCPackage pkg2 = OPCPackage.open(out.toInputStream())) {
                 sheetRels = pkg2.getPartsByName(Pattern.compile("/xl/worksheets/sheet1.xml")).get(0).getRelationships();
                 assertEquals(3, sheetRels.size());
                 rId1 = sheetRels.getRelationshipByID("rId1");
diff --git a/poi-ooxml/src/test/java/org/apache/poi/openxml4j/opc/ZipFileAssert.java b/poi-ooxml/src/test/java/org/apache/poi/openxml4j/opc/ZipFileAssert.java
index 598630546b..9b21bb7db0 100644
--- a/poi-ooxml/src/test/java/org/apache/poi/openxml4j/opc/ZipFileAssert.java
+++ b/poi-ooxml/src/test/java/org/apache/poi/openxml4j/opc/ZipFileAssert.java
@@ -24,7 +24,6 @@ import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.io.BufferedInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.IOException;
@@ -33,6 +32,7 @@ import java.util.TreeMap;
 
 import org.apache.commons.compress.archivers.ArchiveEntry;
 import org.apache.commons.compress.archivers.zip.ZipArchiveInputStream;
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.util.IOUtils;
 import org.junit.jupiter.api.Assertions;
 import org.xmlunit.builder.DiffBuilder;
@@ -52,15 +52,15 @@ public final class ZipFileAssert {
     }
 
     private static void equals(
-            TreeMap<String, ByteArrayOutputStream> file1,
-            TreeMap<String, ByteArrayOutputStream> file2) {
+            TreeMap<String, UnsynchronizedByteArrayOutputStream> file1,
+            TreeMap<String, UnsynchronizedByteArrayOutputStream> file2) {
         Set<String> listFile1 = file1.keySet();
         Assertions.assertEquals(listFile1.size(), file2.keySet().size(), "not the same number of files in zip:");
 
         for (String fileName : listFile1) {
             // extract the contents for both
-            ByteArrayOutputStream contain1 = file1.get(fileName);
-            ByteArrayOutputStream contain2 = file2.get(fileName);
+            UnsynchronizedByteArrayOutputStream contain1 = file1.get(fileName);
+            UnsynchronizedByteArrayOutputStream contain2 = file2.get(fileName);
 
             assertNotNull(contain2, fileName + " not found in 2nd zip");
             // no need to check for contain1. The key come from it
@@ -84,11 +84,11 @@ public final class ZipFileAssert {
         }
     }
 
-    private static TreeMap<String, ByteArrayOutputStream> decompress(
+    private static TreeMap<String, UnsynchronizedByteArrayOutputStream> decompress(
             File filename) throws IOException {
         // store the zip content in memory
         // let s assume it is not Go ;-)
-        TreeMap<String, ByteArrayOutputStream> zipContent = new TreeMap<>();
+        TreeMap<String, UnsynchronizedByteArrayOutputStream> zipContent = new TreeMap<>();
 
         try (
         /* Open file to decompress */
@@ -106,7 +106,7 @@ public final class ZipFileAssert {
             while ((entree = zis.getNextEntry()) != null) {
 
                 /* Create a array for the current entry */
-                ByteArrayOutputStream byteArray = new ByteArrayOutputStream();
+                UnsynchronizedByteArrayOutputStream byteArray = new UnsynchronizedByteArrayOutputStream();
                 IOUtils.copy(zis, byteArray);
                 zipContent.put(entree.getName(), byteArray);
             }
diff --git a/poi-ooxml/src/test/java/org/apache/poi/openxml4j/opc/compliance/TestOPCComplianceCoreProperties.java b/poi-ooxml/src/test/java/org/apache/poi/openxml4j/opc/compliance/TestOPCComplianceCoreProperties.java
index 3ebd4041a3..b079f00bf3 100644
--- a/poi-ooxml/src/test/java/org/apache/poi/openxml4j/opc/compliance/TestOPCComplianceCoreProperties.java
+++ b/poi-ooxml/src/test/java/org/apache/poi/openxml4j/opc/compliance/TestOPCComplianceCoreProperties.java
@@ -17,7 +17,8 @@
 
 package org.apache.poi.openxml4j.opc.compliance;
 
-import static org.apache.poi.openxml4j.OpenXML4JTestDataSamples.openComplianceSampleStream;
+import static org.apache.poi.openxml4j.OpenXML4JTestDataSamples.getOutputFile;
+import static org.apache.poi.openxml4j.OpenXML4JTestDataSamples.getSampleFile;
 import static org.apache.poi.openxml4j.OpenXML4JTestDataSamples.openSampleStream;
 import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
 import static org.junit.jupiter.api.Assertions.assertEquals;
@@ -26,8 +27,6 @@ import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.FileOutputStream;
 import java.io.IOException;
@@ -35,7 +34,7 @@ import java.io.InputStream;
 import java.net.URI;
 import java.net.URISyntaxException;
 
-import org.apache.poi.POIDataSamples;
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.openxml4j.exceptions.InvalidFormatException;
 import org.apache.poi.openxml4j.exceptions.InvalidOperationException;
 import org.apache.poi.openxml4j.opc.ContentTypes;
@@ -44,7 +43,6 @@ import org.apache.poi.openxml4j.opc.PackageRelationshipTypes;
 import org.apache.poi.openxml4j.opc.PackagingURIHelper;
 import org.apache.poi.openxml4j.opc.TargetMode;
 import org.apache.poi.util.IOUtils;
-import org.apache.poi.util.TempFile;
 import org.junit.jupiter.api.Test;
 
 /**
@@ -81,13 +79,13 @@ public final class TestOPCComplianceCoreProperties {
 
     @Test
     void testCorePropertiesPart() throws IOException {
-        try (InputStream is = openComplianceSampleStream("OPCCompliance_CoreProperties_OnlyOneCorePropertiesPart.docx")) {
+        try (InputStream is = openSampleStream("OPCCompliance_CoreProperties_OnlyOneCorePropertiesPart.docx")) {
             assertDoesNotThrow(() -> OPCPackage.open(is).close());
         }
     }
 
     private static String extractInvalidFormatMessage(String sampleNameSuffix) throws IOException {
-        try (InputStream is = openComplianceSampleStream("OPCCompliance_CoreProperties_" + sampleNameSuffix)) {
+        try (InputStream is = openSampleStream("OPCCompliance_CoreProperties_" + sampleNameSuffix)) {
             InvalidFormatException e = assertThrows(InvalidFormatException.class,
                 () -> OPCPackage.open(is).revert(), "expected OPC compliance exception was not thrown");
             return e.getMessage();
@@ -137,7 +135,7 @@ public final class TestOPCComplianceCoreProperties {
      */
     @Test
     void testOnlyOneCorePropertiesPart_AddRelationship() throws IOException, InvalidFormatException {
-        try (InputStream is = openComplianceSampleStream("OPCCompliance_CoreProperties_OnlyOneCorePropertiesPart.docx")) {
+        try (InputStream is = openSampleStream("OPCCompliance_CoreProperties_OnlyOneCorePropertiesPart.docx")) {
             OPCPackage pkg = OPCPackage.open(is);
             URI partUri = createURI("/docProps/core2.xml");
             InvalidOperationException e = assertThrows(InvalidOperationException.class, () ->
@@ -155,7 +153,7 @@ public final class TestOPCComplianceCoreProperties {
     @Test
     void testOnlyOneCorePropertiesPart_AddPart() throws InvalidFormatException, IOException {
         String sampleFileName = "OPCCompliance_CoreProperties_OnlyOneCorePropertiesPart.docx";
-        try (OPCPackage pkg = OPCPackage.open(POIDataSamples.getOpenXML4JInstance().getFile(sampleFileName).getPath())) {
+        try (OPCPackage pkg = OPCPackage.open(getSampleFile(sampleFileName).getPath())) {
 
             URI partUri = createURI("/docProps/core2.xml");
             InvalidOperationException e = assertThrows(InvalidOperationException.class, () ->
@@ -218,9 +216,9 @@ public final class TestOPCComplianceCoreProperties {
     @Test
     void testNoCoreProperties_saveNew() throws Exception {
         String sampleFileName = "OPCCompliance_NoCoreProperties.xlsx";
-        ByteArrayOutputStream baos = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
 
-        try (OPCPackage pkg = OPCPackage.open(POIDataSamples.getOpenXML4JInstance().getFile(sampleFileName).getPath())) {
+        try (OPCPackage pkg = OPCPackage.open(getSampleFile(sampleFileName).getPath())) {
             // Verify it has empty properties
             assertEquals(0, pkg.getPartsByContentType(ContentTypes.CORE_PROPERTIES_PART).size());
             assertNotNull(pkg.getPackageProperties());
@@ -232,7 +230,7 @@ public final class TestOPCComplianceCoreProperties {
             pkg.revert();
         }
 
-        try (OPCPackage pkg = OPCPackage.open(new ByteArrayInputStream(baos.toByteArray()))) {
+        try (OPCPackage pkg = OPCPackage.open(baos.toInputStream())) {
             // An Empty Properties part has been added in the save/load
             assertEquals(1, pkg.getPartsByContentType(ContentTypes.CORE_PROPERTIES_PART).size());
             assertNotNull(pkg.getPackageProperties());
@@ -241,14 +239,14 @@ public final class TestOPCComplianceCoreProperties {
         }
 
         // Open a new copy of it
-        try (OPCPackage pkg = OPCPackage.open(POIDataSamples.getOpenXML4JInstance().getFile(sampleFileName).getPath())) {
+        try (OPCPackage pkg = OPCPackage.open(getSampleFile(sampleFileName).getPath())) {
             // Save and re-load, without having touched the properties yet
             baos.reset();
             pkg.save(baos);
             pkg.revert();
         }
 
-        try (OPCPackage pkg = OPCPackage.open(new ByteArrayInputStream(baos.toByteArray()))) {
+        try (OPCPackage pkg = OPCPackage.open(baos.toInputStream())) {
             // Check that this too added empty properties without error
             assertEquals(1, pkg.getPartsByContentType(ContentTypes.CORE_PROPERTIES_PART).size());
             assertNotNull(pkg.getPackageProperties());
@@ -266,9 +264,9 @@ public final class TestOPCComplianceCoreProperties {
         String sampleFileName = "OPCCompliance_NoCoreProperties.xlsx";
 
         // Copy this into a temp file, so we can play with it
-        File tmp = TempFile.createTempFile("poi-test", ".opc");
+        File tmp = getOutputFile("poi-test.opc");
         try (FileOutputStream out = new FileOutputStream(tmp);
-            InputStream in = POIDataSamples.getOpenXML4JInstance().openResourceAsStream(sampleFileName)) {
+            InputStream in = openSampleStream(sampleFileName)) {
             IOUtils.copy(in, out);
         }
 
diff --git a/poi-ooxml/src/test/java/org/apache/poi/openxml4j/opc/internal/TestContentTypeManager.java b/poi-ooxml/src/test/java/org/apache/poi/openxml4j/opc/internal/TestContentTypeManager.java
index aab917ec63..1fe70833c9 100644
--- a/poi-ooxml/src/test/java/org/apache/poi/openxml4j/opc/internal/TestContentTypeManager.java
+++ b/poi-ooxml/src/test/java/org/apache/poi/openxml4j/opc/internal/TestContentTypeManager.java
@@ -23,12 +23,11 @@ import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertNull;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.util.Arrays;
 import java.util.List;
 
-import org.apache.poi.ooxml.util.POIXMLUnits;
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.openxml4j.OpenXML4JTestDataSamples;
 import org.apache.poi.openxml4j.opc.OPCPackage;
 import org.apache.poi.openxml4j.opc.PackageAccess;
@@ -40,11 +39,9 @@ import org.apache.poi.openxml4j.opc.PackageRelationshipTypes;
 import org.apache.poi.openxml4j.opc.PackagingURIHelper;
 import org.apache.poi.ss.usermodel.ClientAnchor;
 import org.apache.poi.ss.usermodel.CreationHelper;
-import org.apache.poi.ss.usermodel.Drawing;
 import org.apache.poi.ss.usermodel.Sheet;
 import org.apache.poi.ss.usermodel.Workbook;
 import org.apache.poi.xssf.XSSFTestDataSamples;
-import org.apache.poi.xssf.usermodel.XSSFClientAnchor;
 import org.apache.poi.xssf.usermodel.XSSFDrawing;
 import org.apache.poi.xssf.usermodel.XSSFPicture;
 import org.apache.poi.xssf.usermodel.XSSFPictureData;
@@ -53,8 +50,6 @@ import org.apache.poi.xssf.usermodel.XSSFSheet;
 import org.apache.poi.xssf.usermodel.XSSFWorkbook;
 import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
-import org.openxmlformats.schemas.drawingml.x2006.spreadsheetDrawing.CTMarker;
-import org.openxmlformats.schemas.drawingml.x2006.spreadsheetDrawing.CTTwoCellAnchor;
 
 public final class TestContentTypeManager {
 
@@ -137,7 +132,7 @@ public final class TestContentTypeManager {
     }
 
     protected byte[] toByteArray(Workbook wb) {
-        try (ByteArrayOutputStream os = new ByteArrayOutputStream()) {
+        try (UnsynchronizedByteArrayOutputStream os = new UnsynchronizedByteArrayOutputStream()) {
             wb.write(os);
             return os.toByteArray();
         } catch (IOException e) {
diff --git a/poi-ooxml/src/test/java/org/apache/poi/openxml4j/opc/internal/marshallers/TestZipPackagePropertiesMarshaller.java b/poi-ooxml/src/test/java/org/apache/poi/openxml4j/opc/internal/marshallers/TestZipPackagePropertiesMarshaller.java
index 3b9b03aed4..40345a029a 100644
--- a/poi-ooxml/src/test/java/org/apache/poi/openxml4j/opc/internal/marshallers/TestZipPackagePropertiesMarshaller.java
+++ b/poi-ooxml/src/test/java/org/apache/poi/openxml4j/opc/internal/marshallers/TestZipPackagePropertiesMarshaller.java
@@ -17,16 +17,17 @@
 
 package org.apache.poi.openxml4j.opc.internal.marshallers;
 
+import static org.apache.commons.io.output.NullOutputStream.NULL_OUTPUT_STREAM;
 import static org.apache.poi.openxml4j.opc.PackagingURIHelper.PACKAGE_RELATIONSHIPS_ROOT_URI;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.OutputStream;
 
 import org.apache.commons.compress.archivers.ArchiveEntry;
 import org.apache.commons.compress.archivers.zip.ZipArchiveOutputStream;
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.openxml4j.exceptions.OpenXML4JException;
 import org.apache.poi.openxml4j.opc.PackagePartName;
 import org.apache.poi.openxml4j.opc.PackagingURIHelper;
@@ -38,7 +39,7 @@ class TestZipPackagePropertiesMarshaller {
     private final PartMarshaller marshaller = new ZipPackagePropertiesMarshaller();
 
     private boolean marshall() throws OpenXML4JException {
-        return marshall(new ZipArchiveOutputStream(new ByteArrayOutputStream()));
+        return marshall(new ZipArchiveOutputStream(new UnsynchronizedByteArrayOutputStream()));
     }
 
     private boolean marshall(OutputStream zos) throws OpenXML4JException {
@@ -50,8 +51,7 @@ class TestZipPackagePropertiesMarshaller {
 
     @Test
     void nonZipOutputStream() {
-        OutputStream notAZipOutputStream = new ByteArrayOutputStream(0);
-        assertThrows(IllegalArgumentException.class, () -> marshall(notAZipOutputStream));
+        assertThrows(IllegalArgumentException.class, () -> marshall(NULL_OUTPUT_STREAM));
     }
 
     @Test
@@ -61,7 +61,7 @@ class TestZipPackagePropertiesMarshaller {
 
     @Test
     void ioException() {
-        ZipArchiveOutputStream zos = new ZipArchiveOutputStream(new ByteArrayOutputStream()) {
+        ZipArchiveOutputStream zos = new ZipArchiveOutputStream(new UnsynchronizedByteArrayOutputStream()) {
             @Override
             public void putArchiveEntry(final ArchiveEntry archiveEntry) throws IOException {
                 throw new IOException("TestException");
diff --git a/poi-ooxml/src/test/java/org/apache/poi/poifs/crypt/dsig/TestSignatureInfo.java b/poi-ooxml/src/test/java/org/apache/poi/poifs/crypt/dsig/TestSignatureInfo.java
index 52516d0c68..afd498aa12 100644
--- a/poi-ooxml/src/test/java/org/apache/poi/poifs/crypt/dsig/TestSignatureInfo.java
+++ b/poi-ooxml/src/test/java/org/apache/poi/poifs/crypt/dsig/TestSignatureInfo.java
@@ -32,7 +32,6 @@ import static org.junit.jupiter.api.Assumptions.assumeTrue;
 
 import java.io.BufferedReader;
 import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.FileOutputStream;
@@ -77,6 +76,7 @@ import javax.xml.crypto.dsig.CanonicalizationMethod;
 import javax.xml.crypto.dsig.XMLSignatureException;
 import javax.xml.crypto.dsig.dom.DOMSignContext;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.jcp.xml.dsig.internal.dom.DOMSignedInfo;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
@@ -160,6 +160,8 @@ import org.junit.jupiter.api.AfterAll;
 import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
 import org.w3.x2000.x09.xmldsig.ReferenceType;
 import org.w3.x2000.x09.xmldsig.SignatureDocument;
 import org.w3c.dom.Document;
@@ -210,36 +212,36 @@ class TestSignatureInfo {
     @Test
     void bug61182() throws Exception {
         final String pfxInput =
-                "H4sIAAAAAAAAAFXTfzzTeRwH8P2uGRmG6hKSmJh9a2HsuPy60VnHCEU6v86sieZH2Jr2qFl+s+ZHJ5tfUcfKb4uho/OjiFq1qTv5ceFyp0PqEK"+
-                        "fH4+66++Pz+Dwer9fj8f7r9cRzEd4QMBTPRWxDIM14ZN47NfAWsJgL34Bx4at4Lvwdngvd9b8KqgbjQpGbMXzzgRGovytVFTBEzIXU47kQCd4U"+
-                        "ofJPvHl8JwyTjRS55hbKoor3UJLDE1i/PcPKCBAIDATjQlKiK67XjVYdcnkZgD2txroiAUb8W9dtn57DvTsbM+3wIsdocXDEN7TdPKgaSl+tU1"+
-                        "xq9oqiB5yMaZCPho8uUEbFU9U6u3N7lEMLTJGeA0RfX+5FMRrpXPFrbrlJ8uNUCE2H247P28Ckyfqlsy32yeKg/HTbH5JpqUDNw2B32+SaiRw7"+
-                        "ofRMePUpaAoK7KYgmd5ZIc0rLLYjJBfOWCb28xlrGhbpJvdToFdqt5PXVjEz5YOJ6g7W0fskuKW9/iZP0yLEVpR9XkkHmb6tfpcE8YwCdWNCan"+
-                        "LvAsco25JdF1j2/FLAMVU79HdOex07main90dy40511OZtTGZ+TdVd3lKZ7D3clEg9hLESHwSNnZ6239X4yLM4xYSElQ/hqSbwdmiozYG9PhF2"+
-                        "Zf0XaZnxzTK0Iot+rJ3kYoxWTLE8DR9leV62Ywbtlg4mapYOxb3lT7fQ1x4EQ44flh2oFWSPLR8LMbsc6jzJsV6OZ3TrODjHEdw9W+8OD32vd8"+
-                        "XQ6iCaIHcrSOn6qS0TKLr786234eeSAhvAQbEsVn7vrvc/487Be/O2e/+5Y5zRq2zAtz6pfcNyraJNDqMW1inNkgJ3t3VESbZ3pNzyl3KHILs0"+
-                        "51dY6msDYSlWhw40TglXxj9rw95O6gFWIuN012W/vhS50jpKXcao4gc1aLaXtJXxirbRkpZ/0e7a0pD6TDa7+GxEdEEML3VGo9udD5YUKhU3y7"+
-                        "SzWAgN6WIEIglq7LilvCjqIVLIfg8CvVGL9f5iSsCDf5hef4vMxbyvcjINuy06gZu+iPYOWNxjfrwKGYzoqqotK2aywgYVrPMh0JovfkDuN95n"+
-                        "MdVlYHbN1Mnn4TxAwuv+u3AkBlDZvRUUCwoDMUGxeMNPhTaAgWl60xhhBgCBaEMgAACReMAav7n3x598IDYJ9GxGXRAwaPOT/kfO/1AgPqLQkp"+
-                        "MiIVaHthnUS4v2y32e2BjdMPyIImUTBW3cV3R5tjVQm0MOm+D2C5+bBW9vHLjLR4lun4toQiY3Ls/v4bES/OJ4EmpZk5xhL9i5ClofYZNEsxFn"+
-                        "An/q821Tg+Cq9Er4XYGQe8ogjjLJ2b7dUsJ3auFQFNUJF7Ke7yUL2EeYYxl6vz5l4q5u8704mRbFts1E1eWMp6WIy91GPrsVlRGvtuNERfrjfE"+
-                        "YtzUI3Flcv65zJUbUBEzUnTS0fEYso2XyToAl8kb251mUY2o2lJzv5dp/1htmcjeeP2MjxC+3S45ljx7jd52Pv9XAat+ryiauFOF7YgztkoWWD"+
-                        "h62tplPH1bzDV+d0NLdaE5AfVJ09HuUYTFS+iggtvT5Euyk+unj4N2XvzW91n+GNjtgWfKOHmkinUPvYRh70Jv+wlPJrVaT8mL7GxJLqDC9jbv"+
-                        "Gznoiae6es+wQejnk3XjU366MrK/zXxngBYj9J6NnXc9mMiTFLX8WqQ8iTelTAFs2NJzPoDzrBUz4JFIEOa6Dja6dULc68g1jFDTeEHZyra7RZ"+
-                        "2ElqGDEqcNRo3SNX6feMy9EF1GOyZK0Sa87KwjKw8aM68dpsIYjfLcTXaZ6atg0BKfMnl6axeUGEaIFSP7rzj9wjzumRbG3jgUVp2lX5AK/tsO"+
-                        "7R4TQX/9/H6RiN34c9KldmPZZGANXzzTajZS9mR2OSvlJ+F4AgSko4htrMAKFTBu51/5SWNsO1vlRaaG48ZRJ+8PzuHQMdvS36gNpRPi7jhF1S"+
-                        "H3B2ycI4y0VURv6SrqJNUY/X645ZFJQ+eBO+ptG7o8axf1dcqh2beiQk+GRTeZ37LVeUlaeo9vl1/+8tyBfyT2v5lFC5E19WdKIyCuZe7r99Px"+
-                        "D/Od4Qj0TA92+DQnbCQTCMy/wwse9O4gsEebkkpPIP5GBV3Q0YBsj75XE0uSFQ1tCZSW8bNa9MUJZ/nPBfExohHlgGAAA=";
+            "H4sIAAAAAAAAAFXTfzzTeRwH8P2uGRmG6hKSmJh9a2HsuPy60VnHCEU6v86sieZH2Jr2qFl+s+ZHJ5tfUcfKb4uho/OjiFq1qTv5ceFyp0PqEK"+
+            "fH4+66++Pz+Dwer9fj8f7r9cRzEd4QMBTPRWxDIM14ZN47NfAWsJgL34Bx4at4Lvwdngvd9b8KqgbjQpGbMXzzgRGovytVFTBEzIXU47kQCd4U"+
+            "ofJPvHl8JwyTjRS55hbKoor3UJLDE1i/PcPKCBAIDATjQlKiK67XjVYdcnkZgD2txroiAUb8W9dtn57DvTsbM+3wIsdocXDEN7TdPKgaSl+tU1"+
+            "xq9oqiB5yMaZCPho8uUEbFU9U6u3N7lEMLTJGeA0RfX+5FMRrpXPFrbrlJ8uNUCE2H247P28Ckyfqlsy32yeKg/HTbH5JpqUDNw2B32+SaiRw7"+
+            "ofRMePUpaAoK7KYgmd5ZIc0rLLYjJBfOWCb28xlrGhbpJvdToFdqt5PXVjEz5YOJ6g7W0fskuKW9/iZP0yLEVpR9XkkHmb6tfpcE8YwCdWNCan"+
+            "LvAsco25JdF1j2/FLAMVU79HdOex07main90dy40511OZtTGZ+TdVd3lKZ7D3clEg9hLESHwSNnZ6239X4yLM4xYSElQ/hqSbwdmiozYG9PhF2"+
+            "Zf0XaZnxzTK0Iot+rJ3kYoxWTLE8DR9leV62Ywbtlg4mapYOxb3lT7fQ1x4EQ44flh2oFWSPLR8LMbsc6jzJsV6OZ3TrODjHEdw9W+8OD32vd8"+
+            "XQ6iCaIHcrSOn6qS0TKLr786234eeSAhvAQbEsVn7vrvc/487Be/O2e/+5Y5zRq2zAtz6pfcNyraJNDqMW1inNkgJ3t3VESbZ3pNzyl3KHILs0"+
+            "51dY6msDYSlWhw40TglXxj9rw95O6gFWIuN012W/vhS50jpKXcao4gc1aLaXtJXxirbRkpZ/0e7a0pD6TDa7+GxEdEEML3VGo9udD5YUKhU3y7"+
+            "SzWAgN6WIEIglq7LilvCjqIVLIfg8CvVGL9f5iSsCDf5hef4vMxbyvcjINuy06gZu+iPYOWNxjfrwKGYzoqqotK2aywgYVrPMh0JovfkDuN95n"+
+            "MdVlYHbN1Mnn4TxAwuv+u3AkBlDZvRUUCwoDMUGxeMNPhTaAgWl60xhhBgCBaEMgAACReMAav7n3x598IDYJ9GxGXRAwaPOT/kfO/1AgPqLQkp"+
+            "MiIVaHthnUS4v2y32e2BjdMPyIImUTBW3cV3R5tjVQm0MOm+D2C5+bBW9vHLjLR4lun4toQiY3Ls/v4bES/OJ4EmpZk5xhL9i5ClofYZNEsxFn"+
+            "An/q821Tg+Cq9Er4XYGQe8ogjjLJ2b7dUsJ3auFQFNUJF7Ke7yUL2EeYYxl6vz5l4q5u8704mRbFts1E1eWMp6WIy91GPrsVlRGvtuNERfrjfE"+
+            "YtzUI3Flcv65zJUbUBEzUnTS0fEYso2XyToAl8kb251mUY2o2lJzv5dp/1htmcjeeP2MjxC+3S45ljx7jd52Pv9XAat+ryiauFOF7YgztkoWWD"+
+            "h62tplPH1bzDV+d0NLdaE5AfVJ09HuUYTFS+iggtvT5Euyk+unj4N2XvzW91n+GNjtgWfKOHmkinUPvYRh70Jv+wlPJrVaT8mL7GxJLqDC9jbv"+
+            "Gznoiae6es+wQejnk3XjU366MrK/zXxngBYj9J6NnXc9mMiTFLX8WqQ8iTelTAFs2NJzPoDzrBUz4JFIEOa6Dja6dULc68g1jFDTeEHZyra7RZ"+
+            "2ElqGDEqcNRo3SNX6feMy9EF1GOyZK0Sa87KwjKw8aM68dpsIYjfLcTXaZ6atg0BKfMnl6axeUGEaIFSP7rzj9wjzumRbG3jgUVp2lX5AK/tsO"+
+            "7R4TQX/9/H6RiN34c9KldmPZZGANXzzTajZS9mR2OSvlJ+F4AgSko4htrMAKFTBu51/5SWNsO1vlRaaG48ZRJ+8PzuHQMdvS36gNpRPi7jhF1S"+
+            "H3B2ycI4y0VURv6SrqJNUY/X645ZFJQ+eBO+ptG7o8axf1dcqh2beiQk+GRTeZ37LVeUlaeo9vl1/+8tyBfyT2v5lFC5E19WdKIyCuZe7r99Px"+
+            "D/Od4Qj0TA92+DQnbCQTCMy/wwse9O4gsEebkkpPIP5GBV3Q0YBsj75XE0uSFQ1tCZSW8bNa9MUJZ/nPBfExohHlgGAAA=";
 
         // Unix
         final String unixSignExp =
-                "QkqTFQZjXagjRAoOWKpAGa8AR0rKqkSfBtfSWqtjBmTgyjarn+t2POHkpySIpheHAbg+90GKSH88ACMtPHbG7q" +
-                        "FL4gtgAD9Kjew6j16j0IRBwy145UlPrSLFMfF7YF7UlU1k1LBkIlRJ6Fv4MAJl6XspuzZOZIUmHZrWrdxycUQ=";
+            "QkqTFQZjXagjRAoOWKpAGa8AR0rKqkSfBtfSWqtjBmTgyjarn+t2POHkpySIpheHAbg+90GKSH88ACMtPHbG7q" +
+            "FL4gtgAD9Kjew6j16j0IRBwy145UlPrSLFMfF7YF7UlU1k1LBkIlRJ6Fv4MAJl6XspuzZOZIUmHZrWrdxycUQ=";
 
         // Windows
         final String winSignExp =
-                "GmAlL7+bT1r3FsMHJOp3pKg8betblYieZTjhMIrPZPRBbSzjO7KsYRGNtr0aOE3qr8xzyYJN6/8QdF5X7pUEUc" +
-                        "2m8ctrm7s5o2vZTkAqk9ENJGDjBPXX7TnuVOiVeL1cJdtjHC2QpjtRwkFR+B54G6b1OXLOFuQpP3vqR3+/XXE=";
+            "GmAlL7+bT1r3FsMHJOp3pKg8betblYieZTjhMIrPZPRBbSzjO7KsYRGNtr0aOE3qr8xzyYJN6/8QdF5X7pUEUc" +
+            "2m8ctrm7s5o2vZTkAqk9ENJGDjBPXX7TnuVOiVeL1cJdtjHC2QpjtRwkFR+B54G6b1OXLOFuQpP3vqR3+/XXE=";
 
         // Mac
         final String macSignExp =
@@ -259,13 +261,13 @@ class TestSignatureInfo {
         SignatureInfo si = new SignatureInfo();
         si.setSignatureConfig(signatureConfig);
 
-        ByteArrayOutputStream bos = new ByteArrayOutputStream(100000);
+        UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream(100000);
         try (XSSFWorkbook wb1 = new XSSFWorkbook()) {
             wb1.createSheet().createRow(1).createCell(1).setCellValue("Test");
             wb1.write(bos);
         }
 
-        try (OPCPackage pkg1 = OPCPackage.open(new ByteArrayInputStream(bos.toByteArray()))) {
+        try (OPCPackage pkg1 = OPCPackage.open(bos.toInputStream())) {
             si.setOpcPackage(pkg1);
             si.confirmSignature();
             assertTrue(si.verifySignature());
@@ -273,7 +275,7 @@ class TestSignatureInfo {
             pkg1.save(bos);
         }
 
-        try (XSSFWorkbook wb2 = new XSSFWorkbook(new ByteArrayInputStream(bos.toByteArray()))) {
+        try (XSSFWorkbook wb2 = new XSSFWorkbook(bos.toInputStream())) {
             assertEquals("Test", wb2.getSheetAt(0).getRow(1).getCell(1).getStringCellValue());
             OPCPackage pkg2 = wb2.getPackage();
             si.setOpcPackage(pkg2);
@@ -306,71 +308,65 @@ class TestSignatureInfo {
         }
     }
 
-    @Test
-    void getSignerUnsigned() throws Exception {
-        String[] testFiles = {
-                "hello-world-unsigned.docx",
-                "hello-world-unsigned.pptx",
-                "hello-world-unsigned.xlsx",
-                "hello-world-office-2010-technical-preview-unsigned.docx"
-        };
-
-        for (String testFile : testFiles) {
-            List<X509Certificate> result = new ArrayList<>();
-            try (OPCPackage pkg = OPCPackage.open(testdata.getFile(testFile), PackageAccess.READ)) {
-                SignatureConfig sic = new SignatureConfig();
-                SignatureInfo si = new SignatureInfo();
-                si.setOpcPackage(pkg);
-                si.setSignatureConfig(sic);
-                for (SignaturePart sp : si.getSignatureParts()) {
-                    if (sp.validate()) {
-                        result.add(sp.getSigner());
-                    }
+    @ParameterizedTest
+    @ValueSource(strings = {
+        "hello-world-unsigned.docx",
+        "hello-world-unsigned.pptx",
+        "hello-world-unsigned.xlsx",
+        "hello-world-office-2010-technical-preview-unsigned.docx"
+    })
+    void getSignerUnsigned(String testFile) throws Exception {
+        List<X509Certificate> result = new ArrayList<>();
+        try (OPCPackage pkg = OPCPackage.open(testdata.getFile(testFile), PackageAccess.READ)) {
+            SignatureConfig sic = new SignatureConfig();
+            SignatureInfo si = new SignatureInfo();
+            si.setOpcPackage(pkg);
+            si.setSignatureConfig(sic);
+            for (SignaturePart sp : si.getSignatureParts()) {
+                if (sp.validate()) {
+                    result.add(sp.getSigner());
                 }
-                pkg.revert();
             }
-            assertNotNull(result);
-            assertTrue(result.isEmpty());
+            pkg.revert();
         }
+        assertNotNull(result);
+        assertTrue(result.isEmpty());
     }
 
-    @Test
-    void getSigner() throws Exception {
-        String[] testFiles = {
-                "hyperlink-example-signed.docx",
-                "hello-world-signed.docx",
-                "hello-world-signed.pptx",
-                "hello-world-signed.xlsx",
-                "hello-world-office-2010-technical-preview.docx",
-                "ms-office-2010-signed.docx",
-                "ms-office-2010-signed.pptx",
-                "ms-office-2010-signed.xlsx",
-                "Office2010-SP1-XAdES-X-L.docx",
-                "signed.docx"
-        };
-
-        for (String testFile : testFiles) {
-            try (OPCPackage pkg = OPCPackage.open(testdata.getFile(testFile), PackageAccess.READ)) {
-                SignatureConfig sic = new SignatureConfig();
-                SignatureInfo si = new SignatureInfo();
-                si.setOpcPackage(pkg);
-                si.setSignatureConfig(sic);
-                List<X509Certificate> result = new ArrayList<>();
-                for (SignaturePart sp : si.getSignatureParts()) {
-                    if (sp.validate()) {
-                        result.add(sp.getSigner());
-                    }
+    @ParameterizedTest
+    @ValueSource(strings = {
+        "hyperlink-example-signed.docx",
+        "hello-world-signed.docx",
+        "hello-world-signed.pptx",
+        "hello-world-signed.xlsx",
+        "hello-world-office-2010-technical-preview.docx",
+        "ms-office-2010-signed.docx",
+        "ms-office-2010-signed.pptx",
+        "ms-office-2010-signed.xlsx",
+        "Office2010-SP1-XAdES-X-L.docx",
+        "signed.docx"
+    })
+    void getSigner(String testFile) throws Exception {
+        try (OPCPackage pkg = OPCPackage.open(testdata.getFile(testFile), PackageAccess.READ)) {
+            SignatureConfig sic = new SignatureConfig();
+            SignatureInfo si = new SignatureInfo();
+            si.setOpcPackage(pkg);
+            si.setSignatureConfig(sic);
+            List<X509Certificate> result = new ArrayList<>();
+            for (SignaturePart sp : si.getSignatureParts()) {
+                if (sp.validate()) {
+                    result.add(sp.getSigner());
                 }
+            }
 
-                assertNotNull(result);
-                assertEquals(1, result.size(), "test-file: " + testFile);
-                X509Certificate signer = result.get(0);
-                LOG.atDebug().log("signer: {}", signer.getSubjectX500Principal());
+            assertNotNull(result);
+            assertEquals(1, result.size(), "test-file: " + testFile);
+            X509Certificate signer = result.get(0);
+            LOG.atDebug().log("signer: {}", signer.getSubjectX500Principal());
 
-                boolean b = si.verifySignature();
-                assertTrue(b, "test-file: " + testFile);
-                pkg.revert();
-            }
+            boolean b = si.verifySignature();
+            assertTrue(b, "test-file: " + testFile);
+            pkg.revert();
         }
     }
 
@@ -474,7 +470,7 @@ class TestSignatureInfo {
     void testSignEnvelopingDocument() throws Exception {
         String testFile = "hello-world-unsigned.xlsx";
         File sigCopy = testdata.getFile(testFile);
-        ByteArrayOutputStream bos = new ByteArrayOutputStream(50000);
+        UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream(50000);
 
         final String execTimestr;
 
@@ -613,7 +609,7 @@ class TestSignatureInfo {
             pkg.save(bos);
         }
 
-        try (OPCPackage pkg = OPCPackage.open(new ByteArrayInputStream(bos.toByteArray()))) {
+        try (OPCPackage pkg = OPCPackage.open(bos.toInputStream())) {
             SignatureConfig signatureConfig = new SignatureConfig();
             signatureConfig.setUpdateConfigOnValidate(true);
 
@@ -752,7 +748,7 @@ class TestSignatureInfo {
     void bug65214() throws Exception {
         initKeyPair();
 
-	    ByteArrayOutputStream bos = new ByteArrayOutputStream();
+	    UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream();
 	    try (XWPFDocument doc = new XWPFDocument()) {
             XWPFHyperlinkRun r = doc.createParagraph().createHyperlinkRun("http://poi.apache.org");
 	        r.setText("Hyperlink");
@@ -765,7 +761,7 @@ class TestSignatureInfo {
         signatureConfig.setKey(keyPair.getPrivate());
         signatureConfig.setSigningCertificateChain(Collections.singletonList(x509));
         signatureConfig.setDigestAlgo(HashAlgorithm.sha256);
-        try (OPCPackage pkg = OPCPackage.open(new ByteArrayInputStream(bos.toByteArray()))) {
+        try (OPCPackage pkg = OPCPackage.open(bos.toInputStream())) {
             SignatureInfo si = new SignatureInfo();
             si.setOpcPackage(pkg);
             si.setSignatureConfig(signatureConfig);
@@ -776,7 +772,7 @@ class TestSignatureInfo {
             assumeTrue(e.getMessage().startsWith("Export Restrictions"));
         }
 
-        try (OPCPackage pkg = OPCPackage.open(new ByteArrayInputStream(bos.toByteArray()))) {
+        try (OPCPackage pkg = OPCPackage.open(bos.toInputStream())) {
             SignatureInfo si = new SignatureInfo();
             si.setOpcPackage(pkg);
             si.setSignatureConfig(signatureConfig);
@@ -793,10 +789,10 @@ class TestSignatureInfo {
         try (SXSSFWorkbook wb1 = new SXSSFWorkbook((XSSFWorkbook)WorkbookFactory.create(tpl), 10)) {
             wb1.setCompressTempFiles(true);
             wb1.removeSheetAt(0);
-            ByteArrayOutputStream os = new ByteArrayOutputStream();
+            UnsynchronizedByteArrayOutputStream os = new UnsynchronizedByteArrayOutputStream();
             wb1.write(os);
 
-            try (OPCPackage pkg = OPCPackage.open(new ByteArrayInputStream(os.toByteArray()))) {
+            try (OPCPackage pkg = OPCPackage.open(os.toInputStream())) {
                 initKeyPair();
                 SignatureConfig signatureConfig = new SignatureConfig();
                 signatureConfig.setKey(keyPair.getPrivate());
diff --git a/poi-ooxml/src/test/java/org/apache/poi/poifs/crypt/tests/TestAgileEncryptionParameters.java b/poi-ooxml/src/test/java/org/apache/poi/poifs/crypt/tests/TestAgileEncryptionParameters.java
index 14e6debbf4..27930ce1d0 100644
--- a/poi-ooxml/src/test/java/org/apache/poi/poifs/crypt/tests/TestAgileEncryptionParameters.java
+++ b/poi-ooxml/src/test/java/org/apache/poi/poifs/crypt/tests/TestAgileEncryptionParameters.java
@@ -20,8 +20,6 @@ import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 import static org.junit.jupiter.api.Assumptions.assumeTrue;
 
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.InputStream;
 import java.io.OutputStream;
 import java.util.ArrayList;
@@ -30,6 +28,7 @@ import java.util.stream.Stream;
 
 import javax.crypto.Cipher;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.POIDataSamples;
 import org.apache.poi.poifs.crypt.ChainingMode;
 import org.apache.poi.poifs.crypt.CipherAlgorithm;
@@ -79,7 +78,7 @@ class TestAgileEncryptionParameters {
         int maxKeyLen = Cipher.getMaxAllowedKeyLength(ca.jceId);
         assumeTrue(maxKeyLen >= ca.defaultKeySize, "Please install JCE Unlimited Strength Jurisdiction Policy files");
 
-        ByteArrayOutputStream bos = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream();
 
         POIFSFileSystem fsEnc = new POIFSFileSystem();
         EncryptionInfo infoEnc = new EncryptionInfo(EncryptionMode.agile, ca, ha, -1, -1, cm);
@@ -92,7 +91,7 @@ class TestAgileEncryptionParameters {
         fsEnc.writeFilesystem(bos);
         fsEnc.close();
 
-        POIFSFileSystem fsDec = new POIFSFileSystem(new ByteArrayInputStream(bos.toByteArray()));
+        POIFSFileSystem fsDec = new POIFSFileSystem(bos.toInputStream());
         EncryptionInfo infoDec = new EncryptionInfo(fsDec);
         Decryptor dec = infoDec.getDecryptor();
         boolean passed = dec.verifyPassword("foobaa");
diff --git a/poi-ooxml/src/test/java/org/apache/poi/poifs/crypt/tests/TestDecryptor.java b/poi-ooxml/src/test/java/org/apache/poi/poifs/crypt/tests/TestDecryptor.java
index fed15e2f3c..4be8a9b674 100644
--- a/poi-ooxml/src/test/java/org/apache/poi/poifs/crypt/tests/TestDecryptor.java
+++ b/poi-ooxml/src/test/java/org/apache/poi/poifs/crypt/tests/TestDecryptor.java
@@ -22,7 +22,6 @@ import static org.junit.jupiter.api.Assertions.assertTrue;
 import static org.junit.jupiter.api.Assumptions.assumeTrue;
 
 import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
@@ -34,6 +33,7 @@ import javax.crypto.Cipher;
 import org.apache.commons.codec.binary.Base64;
 import org.apache.commons.compress.archivers.zip.ZipArchiveEntry;
 import org.apache.commons.compress.archivers.zip.ZipArchiveInputStream;
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.POIDataSamples;
 import org.apache.poi.poifs.crypt.CryptoFunctions;
 import org.apache.poi.poifs.crypt.Decryptor;
@@ -142,7 +142,7 @@ class TestDecryptor {
             Decryptor d = Decryptor.getInstance(info);
             d.verifyPassword("pwd123");
 
-            final ByteArrayOutputStream bos = new ByteArrayOutputStream(10000);
+            final UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream(10000);
             try (final ZipArchiveInputStream zis = new ZipArchiveInputStream(d.getDataStream(fs))) {
                 int[] sizes = { 3711, 1155, 445, 9376, 450, 588, 1337, 2593, 304, 7910 };
                 for (int size : sizes) {
diff --git a/poi-ooxml/src/test/java/org/apache/poi/poifs/crypt/tests/TestEncryptor.java b/poi-ooxml/src/test/java/org/apache/poi/poifs/crypt/tests/TestEncryptor.java
index ed2ee87e02..4cd6e0e1fd 100644
--- a/poi-ooxml/src/test/java/org/apache/poi/poifs/crypt/tests/TestEncryptor.java
+++ b/poi-ooxml/src/test/java/org/apache/poi/poifs/crypt/tests/TestEncryptor.java
@@ -16,6 +16,7 @@
 ==================================================================== */
 package org.apache.poi.poifs.crypt.tests;
 
+import static org.apache.commons.io.output.NullOutputStream.NULL_OUTPUT_STREAM;
 import static org.apache.poi.poifs.crypt.CryptoFunctions.getMessageDigest;
 import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertEquals;
@@ -24,8 +25,6 @@ import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 import static org.junit.jupiter.api.Assumptions.assumeTrue;
 
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.FileOutputStream;
 import java.io.IOException;
@@ -39,6 +38,7 @@ import java.util.Random;
 
 import javax.crypto.Cipher;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.POIDataSamples;
 import org.apache.poi.openxml4j.opc.ContentTypes;
 import org.apache.poi.openxml4j.opc.OPCPackage;
@@ -59,7 +59,6 @@ import org.apache.poi.poifs.filesystem.Entry;
 import org.apache.poi.poifs.filesystem.POIFSFileSystem;
 import org.apache.poi.poifs.filesystem.TempFilePOIFSFileSystem;
 import org.apache.poi.util.IOUtils;
-import org.apache.poi.util.NullOutputStream;
 import org.apache.poi.util.TempFile;
 import org.apache.poi.xwpf.usermodel.XWPFDocument;
 import org.apache.poi.xwpf.usermodel.XWPFParagraph;
@@ -78,7 +77,7 @@ class TestEncryptor {
             payloadExpected = IOUtils.toByteArray(is);
         }
 
-        ByteArrayOutputStream bos = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream();
         try (POIFSFileSystem fs = new POIFSFileSystem()) {
             EncryptionInfo ei = new EncryptionInfo(EncryptionMode.binaryRC4);
             Encryptor enc = ei.getEncryptor();
@@ -92,7 +91,7 @@ class TestEncryptor {
         }
 
         final byte[] payloadActual;
-        try (POIFSFileSystem fs = new POIFSFileSystem(new ByteArrayInputStream(bos.toByteArray()))) {
+        try (POIFSFileSystem fs = new POIFSFileSystem(bos.toInputStream())) {
             EncryptionInfo ei = new EncryptionInfo(fs);
             Decryptor dec = ei.getDecryptor();
             boolean b = dec.verifyPassword(password);
@@ -115,7 +114,7 @@ class TestEncryptor {
             payloadExpected = IOUtils.toByteArray(is);
         }
 
-        ByteArrayOutputStream bos = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream();
         try (POIFSFileSystem fs = new TempFilePOIFSFileSystem()) {
             EncryptionInfo ei = new EncryptionInfo(EncryptionMode.agile);
             Encryptor enc = ei.getEncryptor();
@@ -129,7 +128,7 @@ class TestEncryptor {
         }
 
         final byte[] payloadActual;
-        try (POIFSFileSystem fs = new POIFSFileSystem(new ByteArrayInputStream(bos.toByteArray()))) {
+        try (POIFSFileSystem fs = new POIFSFileSystem(bos.toInputStream())) {
             EncryptionInfo ei = new EncryptionInfo(fs);
             Decryptor dec = ei.getDecryptor();
             boolean b = dec.verifyPassword(password);
@@ -202,7 +201,7 @@ class TestEncryptor {
         Encryptor e = Encryptor.getInstance(infoActual);
         e.confirmPassword(pass, keySpec, keySalt, verifierExpected, verifierSaltExpected, integritySalt);
 
-        ByteArrayOutputStream bos = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream();
         try (POIFSFileSystem fs = new POIFSFileSystem()) {
             try (OutputStream os = e.getDataStream(fs)) {
                 os.write(payloadExpected);
@@ -213,7 +212,7 @@ class TestEncryptor {
         final EncryptionInfo infoActual2;
         final byte[] payloadActual, encPackActual;
         final long decPackLenActual;
-        try (POIFSFileSystem nfs = new POIFSFileSystem(new ByteArrayInputStream(bos.toByteArray()))) {
+        try (POIFSFileSystem nfs = new POIFSFileSystem(bos.toInputStream())) {
             infoActual2 = new EncryptionInfo(nfs.getRoot());
             Decryptor decActual = Decryptor.getInstance(infoActual2);
             boolean passed = decActual.verifyPassword(pass);
@@ -289,7 +288,7 @@ class TestEncryptor {
         // now we use a newly generated salt/verifier and check
         // if the file content is still the same
 
-        final byte[] encBytes;
+        final UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream(50000);
         try (POIFSFileSystem fs = new POIFSFileSystem()) {
 
             final EncryptionInfo infoActual2 = new EncryptionInfo(
@@ -308,13 +307,11 @@ class TestEncryptor {
                 os.write(payloadExpected);
             }
 
-            final ByteArrayOutputStream bos = new ByteArrayOutputStream(50000);
             fs.writeFilesystem(bos);
-            encBytes = bos.toByteArray();
         }
 
         final byte[] payloadActual;
-        try (POIFSFileSystem nfs = new POIFSFileSystem(new ByteArrayInputStream(encBytes))) {
+        try (POIFSFileSystem nfs = new POIFSFileSystem(bos.toInputStream())) {
             final EncryptionInfo ei = new EncryptionInfo(nfs);
             Decryptor d2 = Decryptor.getInstance(ei);
             assertTrue(d2.verifyPassword(pass), "Unable to process: document is encrypted");
@@ -336,7 +333,7 @@ class TestEncryptor {
     @Test
     void encryptPackageWithoutCoreProperties() throws Exception {
         // Open our file without core properties
-        final byte[] encBytes;
+        UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
         try (InputStream is = POIDataSamples.getOpenXML4JInstance().openResourceAsStream("OPCCompliance_NoCoreProperties.xlsx");
             OPCPackage pkg = OPCPackage.open(is)) {
 
@@ -358,14 +355,12 @@ class TestEncryptor {
                 }
 
                 // Save the resulting OLE2 document, and re-open it
-                ByteArrayOutputStream baos = new ByteArrayOutputStream();
                 fs.writeFilesystem(baos);
-                encBytes = baos.toByteArray();
             }
         }
 
 
-        try (POIFSFileSystem inpFS = new POIFSFileSystem(new ByteArrayInputStream(encBytes))) {
+        try (POIFSFileSystem inpFS = new POIFSFileSystem(baos.toInputStream())) {
             // Check we can decrypt it
             EncryptionInfo info = new EncryptionInfo(inpFS);
             Decryptor d = Decryptor.getInstance(info);
@@ -539,10 +534,10 @@ class TestEncryptor {
                 os.write(zipInput);
             }
 
-            ByteArrayOutputStream bos = new ByteArrayOutputStream();
+            UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream();
             fsNew.writeFilesystem(bos);
 
-            try (POIFSFileSystem fsReload = new POIFSFileSystem(new ByteArrayInputStream(bos.toByteArray()))) {
+            try (POIFSFileSystem fsReload = new POIFSFileSystem(bos.toInputStream())) {
                 infoReload = new EncryptionInfo(fsReload);
                 try (InputStream epReload = fsReload.getRoot().createDocumentInputStream("EncryptedPackage")) {
                     epNewBytes = IOUtils.toByteArray(epReload, 9400);
@@ -633,9 +628,8 @@ class TestEncryptor {
             assertTrue(passOk);
 
             try (InputStream is = dec.getDataStream(poifs);
-                 DigestInputStream dis = new DigestInputStream(is, md);
-                 NullOutputStream nos = new NullOutputStream()) {
-                IOUtils.copy(dis, nos);
+                 DigestInputStream dis = new DigestInputStream(is, md)) {
+                IOUtils.copy(dis, NULL_OUTPUT_STREAM);
             }
         }
 
diff --git a/poi-ooxml/src/test/java/org/apache/poi/poifs/crypt/tests/TestHxxFEncryption.java b/poi-ooxml/src/test/java/org/apache/poi/poifs/crypt/tests/TestHxxFEncryption.java
index bf5aebb590..6f4f27c486 100644
--- a/poi-ooxml/src/test/java/org/apache/poi/poifs/crypt/tests/TestHxxFEncryption.java
+++ b/poi-ooxml/src/test/java/org/apache/poi/poifs/crypt/tests/TestHxxFEncryption.java
@@ -26,28 +26,20 @@ import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertNull;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.File;
-import java.io.FileInputStream;
-import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.nio.charset.StandardCharsets;
 import java.util.stream.Stream;
 
-import org.apache.poi.hssf.model.WorkbookRecordList;
-import org.apache.poi.hssf.record.FilePassRecord;
-
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.POIDataSamples;
 import org.apache.poi.POIDocument;
 import org.apache.poi.extractor.ExtractorFactory;
 import org.apache.poi.extractor.POITextExtractor;
-import org.apache.poi.hssf.record.Record;
 import org.apache.poi.hssf.record.crypto.Biff8EncryptionKey;
 import org.apache.poi.hssf.usermodel.HSSFWorkbook;
 import org.apache.poi.poifs.crypt.EncryptionInfo;
 import org.apache.poi.poifs.crypt.EncryptionMode;
-import org.apache.poi.poifs.crypt.binaryrc4.BinaryRC4EncryptionHeader;
 import org.apache.poi.poifs.crypt.cryptoapi.CryptoAPIEncryptionHeader;
 import org.apache.poi.poifs.storage.RawDataUtil;
 import org.junit.jupiter.api.Test;
@@ -110,14 +102,13 @@ class TestHxxFEncryption {
     private void newPassword(String newPass, POIDataSamples sampleDir, String file, String password, String expected) throws IOException {
         File f = sampleDir.getFile(file);
         Biff8EncryptionKey.setCurrentUserPassword(password);
-        try (POITextExtractor te1 = ExtractorFactory.createExtractor(f)) {
+        try (POITextExtractor te1 = ExtractorFactory.createExtractor(f);
+             UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream()) {
             Biff8EncryptionKey.setCurrentUserPassword(newPass);
-            ByteArrayOutputStream bos = new ByteArrayOutputStream();
             try (POIDocument doc = (POIDocument) te1.getDocument()) {
                 doc.write(bos);
             }
-            ByteArrayInputStream bis = new ByteArrayInputStream(bos.toByteArray());
-            try (POITextExtractor te2 = ExtractorFactory.createExtractor(bis)) {
+            try (POITextExtractor te2 = ExtractorFactory.createExtractor(bos.toInputStream())) {
                 String actual = te2.getText().trim();
                 assertEquals(expected, actual);
             }
@@ -131,9 +122,9 @@ class TestHxxFEncryption {
     @MethodSource("data")
     void changeEncryption(POIDataSamples sampleDir, String file, String password, String expected) throws IOException {
         File f = sampleDir.getFile(file);
-        ByteArrayOutputStream bos = new ByteArrayOutputStream();
         Biff8EncryptionKey.setCurrentUserPassword(password);
-        try (POITextExtractor te1 = ExtractorFactory.createExtractor(f)) {
+        try (POITextExtractor te1 = ExtractorFactory.createExtractor(f);
+             UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream()) {
             // first remove encryption
             Biff8EncryptionKey.setCurrentUserPassword(null);
             try (POIDocument doc = (POIDocument) te1.getDocument()) {
@@ -141,7 +132,7 @@ class TestHxxFEncryption {
             }
             // then use default setting, which is cryptoapi
             String newPass = "newPass";
-            try (POITextExtractor te2 = ExtractorFactory.createExtractor(new ByteArrayInputStream(bos.toByteArray()))) {
+            try (POITextExtractor te2 = ExtractorFactory.createExtractor(bos.toInputStream())) {
                 Biff8EncryptionKey.setCurrentUserPassword(newPass);
                 try (POIDocument doc = (POIDocument) te2.getDocument()) {
                     bos.reset();
@@ -149,7 +140,7 @@ class TestHxxFEncryption {
                 }
             }
             // and finally update cryptoapi setting
-            try (POITextExtractor te3 = ExtractorFactory.createExtractor(new ByteArrayInputStream(bos.toByteArray()));
+            try (POITextExtractor te3 = ExtractorFactory.createExtractor(bos.toInputStream());
                  POIDocument doc = (POIDocument) te3.getDocument()) {
                 // need to cache data (i.e. read all data) before changing the key size
                 Class<?> clazz = doc.getClass();
@@ -167,7 +158,7 @@ class TestHxxFEncryption {
                 doc.write(bos);
             }
             // check the setting
-            try (POITextExtractor te4 = ExtractorFactory.createExtractor(new ByteArrayInputStream(bos.toByteArray()));
+            try (POITextExtractor te4 = ExtractorFactory.createExtractor(bos.toInputStream());
                  POIDocument doc = (POIDocument) te4.getDocument()) {
                 EncryptionInfo ei = doc.getEncryptionInfo();
                 assertNotNull(ei);
@@ -181,7 +172,7 @@ class TestHxxFEncryption {
 
     @Test
     public void changeEncryptionMode() throws IOException {
-        ByteArrayOutputStream bos = new ByteArrayOutputStream(10_000);
+        UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream(10_000);
 
         try (HSSFWorkbook wb = new HSSFWorkbook()) {
             wb.createSheet().createRow(1).createCell(1).setCellValue("Test");
@@ -189,7 +180,7 @@ class TestHxxFEncryption {
             wb.write(bos);
         }
 
-        try (HSSFWorkbook wb = new HSSFWorkbook(new ByteArrayInputStream(bos.toByteArray()))) {
+        try (HSSFWorkbook wb = new HSSFWorkbook(bos.toInputStream())) {
             assertEquals(EncryptionMode.cryptoAPI, wb.getEncryptionMode());
             wb.setEncryptionMode(EncryptionMode.binaryRC4);
             Biff8EncryptionKey.setCurrentUserPassword("test2");
@@ -197,7 +188,7 @@ class TestHxxFEncryption {
             wb.write(bos);
         }
 
-        try (HSSFWorkbook wb = new HSSFWorkbook(new ByteArrayInputStream(bos.toByteArray()))) {
+        try (HSSFWorkbook wb = new HSSFWorkbook(bos.toInputStream())) {
             assertEquals(EncryptionMode.binaryRC4, wb.getEncryptionMode());
             wb.setEncryptionMode(null);
             bos.reset();
@@ -206,7 +197,7 @@ class TestHxxFEncryption {
 
         assertNull(Biff8EncryptionKey.getCurrentUserPassword());
 
-        try (HSSFWorkbook wb = new HSSFWorkbook(new ByteArrayInputStream(bos.toByteArray()))) {
+        try (HSSFWorkbook wb = new HSSFWorkbook(bos.toInputStream())) {
             assertNull(wb.getEncryptionMode());
             wb.setEncryptionMode(null);
             assertEquals("Test", wb.getSheetAt(0).getRow(1).getCell(1).getStringCellValue());
diff --git a/poi-ooxml/src/test/java/org/apache/poi/sl/tests/TestOleShape.java b/poi-ooxml/src/test/java/org/apache/poi/sl/tests/TestOleShape.java
index bda636d2ad..8352e0061c 100644
--- a/poi-ooxml/src/test/java/org/apache/poi/sl/tests/TestOleShape.java
+++ b/poi-ooxml/src/test/java/org/apache/poi/sl/tests/TestOleShape.java
@@ -29,8 +29,6 @@ import static org.junit.jupiter.api.Assertions.fail;
 import static org.junit.jupiter.api.Assumptions.assumeFalse;
 
 import java.awt.geom.Rectangle2D;
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
@@ -39,6 +37,7 @@ import java.lang.reflect.Constructor;
 import java.lang.reflect.Method;
 import java.util.stream.Stream;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.POIDataSamples;
 import org.apache.poi.POIDocument;
 import org.apache.poi.hssf.usermodel.HSSFWorkbook;
@@ -114,7 +113,7 @@ class TestOleShape {
     @ParameterizedTest
     @MethodSource("data")
     void embedData(Api api, ObjectMetaData.Application app) throws IOException, ReflectiveOperationException {
-        final ByteArrayInputStream pptBytes;
+        final UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream(50000);
         try (SlideShow<?,?> ppt = createSlideShow(api)) {
             final PictureData picData = ppt.addPicture(pictureFile,  PictureType.EMF);
             final Slide<?,?> slide = ppt.createSlide();
@@ -123,11 +122,9 @@ class TestOleShape {
             try (OutputStream os = oleShape.updateObjectData(app, null)) {
                 fillOleData(app, os);
             }
-            final ByteArrayOutputStream bos = new ByteArrayOutputStream(50000);
             ppt.write(bos);
-            pptBytes = new ByteArrayInputStream(bos.toByteArray());
         }
-        try (SlideShow<?,?> ppt = SlideShowFactory.create(pptBytes)) {
+        try (SlideShow<?,?> ppt = SlideShowFactory.create(bos.toInputStream())) {
             final ObjectShape<?,?> oleShape = (ObjectShape<?,?>)ppt.getSlides().get(0).getShapes().get(0);
             try (InputStream bis = oleShape.readObjectData()) {
                 validateOleData(app, bis);
diff --git a/poi-ooxml/src/test/java/org/apache/poi/sl/tests/TestSlide.java b/poi-ooxml/src/test/java/org/apache/poi/sl/tests/TestSlide.java
index eb066e4688..06c358a459 100644
--- a/poi-ooxml/src/test/java/org/apache/poi/sl/tests/TestSlide.java
+++ b/poi-ooxml/src/test/java/org/apache/poi/sl/tests/TestSlide.java
@@ -24,11 +24,10 @@ import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 import static org.junit.jupiter.api.Assumptions.assumeFalse;
 
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.sl.usermodel.Slide;
 import org.apache.poi.sl.usermodel.SlideShow;
 import org.apache.poi.sl.usermodel.SlideShowFactory;
@@ -56,10 +55,10 @@ class TestSlide {
         ppt1.createSlide().setHidden(true);
         ppt1.createSlide();
 
-        try (ByteArrayOutputStream bos = new ByteArrayOutputStream()) {
+        try (UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream()) {
             ppt1.write(bos);
 
-            try (InputStream is = new ByteArrayInputStream(bos.toByteArray());
+            try (InputStream is = bos.toInputStream();
                  SlideShow<?, ?> ppt2 = SlideShowFactory.create(is)) {
 
                 Boolean[] hiddenState = ppt2.getSlides().stream().map(Slide::isHidden).toArray(Boolean[]::new);
diff --git a/poi-ooxml/src/test/java/org/apache/poi/sl/tests/TestTable.java b/poi-ooxml/src/test/java/org/apache/poi/sl/tests/TestTable.java
index cedb11eed0..ccd6d86aa5 100644
--- a/poi-ooxml/src/test/java/org/apache/poi/sl/tests/TestTable.java
+++ b/poi-ooxml/src/test/java/org/apache/poi/sl/tests/TestTable.java
@@ -29,11 +29,9 @@ import static org.junit.jupiter.api.Assertions.assertTrue;
 import static org.junit.jupiter.api.Assumptions.assumeFalse;
 
 import java.awt.geom.Rectangle2D;
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
-import java.io.InputStream;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.sl.usermodel.Slide;
 import org.apache.poi.sl.usermodel.SlideShow;
 import org.apache.poi.sl.usermodel.SlideShowFactory;
@@ -42,6 +40,8 @@ import org.apache.poi.sl.usermodel.TableShape;
 import org.apache.poi.sl.usermodel.TextShape.TextDirection;
 import org.apache.poi.xslf.usermodel.XMLSlideShow;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
 
 class TestTable {
 
@@ -51,26 +51,23 @@ class TestTable {
 
         // Test of table dimensions of same slideshow saved as ppt/x
         // to check if both return similar (points) value
-        SlideShow<?,?> ppt = openSampleSlideshow("table_test.ppt");
-        TableShape<?,?> ts = (TableShape<?,?>)ppt.getSlides().get(0).getShapes().get(0);
-
-        SlideShow<?,?> pptx = openSampleSlideshow("table_test.pptx");
-        TableShape<?,?> tsx = (TableShape<?,?>)pptx.getSlides().get(0).getShapes().get(0);
-
-        // assume table shape should be equal to itself
-        confirmTableShapeEqual(ts, ts);
-        confirmTableShapeEqual(tsx, tsx);
-
-        // assert ppt and pptx versions of the same table have the same shape
-        confirmTableShapeEqual(ts, tsx);
-
-        // change row height and validate again
-        tsx.setRowHeight(1, 50);
-        ts.setRowHeight(1, 50);
-        confirmTableShapeEqual(ts, tsx);
-
-        pptx.close();
-        ppt.close();
+        try (SlideShow<?,?> ppt = openSampleSlideshow("table_test.ppt");
+             SlideShow<?,?> pptx = openSampleSlideshow("table_test.pptx")) {
+            TableShape<?, ?> ts = (TableShape<?, ?>) ppt.getSlides().get(0).getShapes().get(0);
+            TableShape<?, ?> tsx = (TableShape<?, ?>) pptx.getSlides().get(0).getShapes().get(0);
+
+            // assume table shape should be equal to itself
+            confirmTableShapeEqual(ts, ts);
+            confirmTableShapeEqual(tsx, tsx);
+
+            // assert ppt and pptx versions of the same table have the same shape
+            confirmTableShapeEqual(ts, tsx);
+
+            // change row height and validate again
+            tsx.setRowHeight(1, 50);
+            ts.setRowHeight(1, 50);
+            confirmTableShapeEqual(ts, tsx);
+        }
     }
 
     private void confirmTableShapeEqual(TableShape<?,?> tableA, TableShape<?,?> tableB) {
@@ -95,16 +92,16 @@ class TestTable {
     @Test
     void directionHSLF() throws IOException {
         assumeFalse(xslfOnly());
-        SlideShow<?,?> ppt1 = SlideShowFactory.create(false);
-        testTextDirection(ppt1);
-        ppt1.close();
+        try (SlideShow<?,?> ppt1 = SlideShowFactory.create(false)) {
+            testTextDirection(ppt1);
+        }
     }
 
     @Test
     void directionXSLF() throws IOException {
-        SlideShow<?,?> ppt1 = new XMLSlideShow();
-        testTextDirection(ppt1);
-        ppt1.close();
+        try (SlideShow<?,?> ppt1 = new XMLSlideShow()) {
+            testTextDirection(ppt1);
+        }
     }
 
     private void testTextDirection(SlideShow<?,?> ppt1) throws IOException {
@@ -128,27 +125,26 @@ class TestTable {
             }
         }
 
-        ByteArrayOutputStream bos = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream();
         ppt1.write(bos);
-        ppt1.close();
 
-        InputStream is = new ByteArrayInputStream(bos.toByteArray());
-        SlideShow<?,?> ppt2 = SlideShowFactory.create(is);
-        TableShape<?,?> tbl2 = (TableShape<?,?>)ppt2.getSlides().get(0).getShapes().get(0);
+        try (SlideShow<?,?> ppt2 = SlideShowFactory.create(bos.toInputStream())) {
+            TableShape<?, ?> tbl2 = (TableShape<?, ?>) ppt2.getSlides().get(0).getShapes().get(0);
 
-        col = 0;
-        for (TextDirection td : tds) {
-            TableCell<?,?> c = tbl2.getCell(0, col++);
-            assertEquals(td, c.getTextDirection());
+            col = 0;
+            for (TextDirection td : tds) {
+                TableCell<?, ?> c = tbl2.getCell(0, col++);
+                assertEquals(td, c.getTextDirection());
+            }
         }
-        ppt2.close();
     }
 
-    @Test
-    void tableSpan() throws IOException {
-        String[] files = (xslfOnly()) ? new String[]{"bug60993.pptx"} : new String[]{"bug60993.pptx", "bug60993.ppt"};
-        for (String f : files) {
-            SlideShow<?,?> ppt = openSampleSlideshow(f);
+    @ParameterizedTest
+    @ValueSource(strings = {"bug60993.pptx", "bug60993.ppt"})
+    void tableSpan(String file) throws IOException {
+        assumeFalse(file.endsWith("ppt") && xslfOnly());
+
+        try (SlideShow<?,?> ppt = openSampleSlideshow(file)) {
             Slide<?,?> slide = ppt.getSlides().get(0);
             TableShape<?,?> ts = (TableShape<?,?>)slide.getShapes().get(0);
             int cols = ts.getNumberOfColumns();
@@ -157,11 +153,11 @@ class TestTable {
                 for (int c=0; c<cols; c++) {
                     TableCell<?,?> tc = ts.getCell(r, c);
                     int rc = r*10+c;
-                    String msg = f+" (r"+r+",c"+c+")";
+                    String msg = file+" (r"+r+",c"+c+")";
                     switch (rc) {
                         case 22:
                         case 51:
-                            if (f.endsWith("ppt")) {
+                            if (file.endsWith("ppt")) {
                                 assertNull(tc, msg);
                             } else {
                                 assertNotNull(tc, msg);
@@ -189,7 +185,6 @@ class TestTable {
                     }
                 }
             }
-            ppt.close();
         }
     }
 }
\ No newline at end of file
diff --git a/poi-ooxml/src/test/java/org/apache/poi/ss/tests/usermodel/TestEmbedOLEPackage.java b/poi-ooxml/src/test/java/org/apache/poi/ss/tests/usermodel/TestEmbedOLEPackage.java
index 001ea8ebce..4c085df879 100644
--- a/poi-ooxml/src/test/java/org/apache/poi/ss/tests/usermodel/TestEmbedOLEPackage.java
+++ b/poi-ooxml/src/test/java/org/apache/poi/ss/tests/usermodel/TestEmbedOLEPackage.java
@@ -24,7 +24,6 @@ import static org.junit.jupiter.api.Assertions.assertTrue;
 import static org.junit.jupiter.api.Assumptions.assumeFalse;
 
 import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.security.MessageDigest;
@@ -35,6 +34,7 @@ import java.util.List;
 import java.util.Locale;
 
 import org.apache.commons.codec.binary.Base64;
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.POIDataSamples;
 import org.apache.poi.hpsf.ClassIDPredefined;
 import org.apache.poi.hssf.HSSFTestDataSamples;
@@ -121,9 +121,9 @@ class TestEmbedOLEPackage {
 
             try (POIFSFileSystem scratchFS = new POIFSFileSystem();
                 POIFSFileSystem ole1FS = new POIFSFileSystem(new ByteArrayInputStream(oleShapes.get(0).getObjectData()))) {
-                ByteArrayOutputStream bos = new ByteArrayOutputStream();
+                UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream();
                 scratch.writeOut(bos);
-                scratchFS.createDocument(new ByteArrayInputStream(bos.toByteArray()), Ole10Native.OLE10_NATIVE);
+                scratchFS.createDocument(bos.toInputStream(), Ole10Native.OLE10_NATIVE);
                 scratchFS.getRoot().setStorageClsid(ClassIDPredefined.OLE_V1_PACKAGE.getClassID());
                 assertTrue(EntryUtils.areDirectoriesIdentical(ole1FS.getRoot(), scratchFS.getRoot()));
             }
@@ -220,7 +220,7 @@ class TestEmbedOLEPackage {
         sh1.setAnchor(new java.awt.Rectangle(50, 50, 100, 200));
         sh1.setFillColor(java.awt.Color.red);
 
-        ByteArrayOutputStream bos = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream();
         ppt.write(bos);
         ppt.close();
 
diff --git a/poi-ooxml/src/test/java/org/apache/poi/xslf/TestXSLFBugs.java b/poi-ooxml/src/test/java/org/apache/poi/xslf/TestXSLFBugs.java
index 08250192ac..5b239a8ad6 100644
--- a/poi-ooxml/src/test/java/org/apache/poi/xslf/TestXSLFBugs.java
+++ b/poi-ooxml/src/test/java/org/apache/poi/xslf/TestXSLFBugs.java
@@ -20,6 +20,7 @@ import static org.apache.poi.POITestCase.assertContains;
 import static org.apache.poi.sl.draw.DrawTextParagraph.HYPERLINK_HREF;
 import static org.apache.poi.sl.draw.DrawTextParagraph.HYPERLINK_LABEL;
 import static org.apache.poi.xslf.XSLFTestDataSamples.openSampleDocument;
+import static org.apache.poi.xslf.XSLFTestDataSamples.writeOutAndReadBack;
 import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
 import static org.junit.jupiter.api.Assertions.assertEquals;
@@ -32,7 +33,6 @@ import static org.junit.jupiter.api.Assumptions.assumeFalse;
 import java.awt.Color;
 import java.awt.geom.Rectangle2D;
 import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.net.URI;
@@ -76,13 +76,15 @@ import org.apache.poi.sl.usermodel.TextRun;
 import org.apache.poi.sl.usermodel.TextShape;
 import org.apache.poi.sl.usermodel.VerticalAlignment;
 import org.apache.poi.util.IOUtils;
-import org.apache.poi.util.NullPrintStream;
+import org.apache.commons.io.output.NullPrintStream;
 import org.apache.poi.xslf.usermodel.*;
 import org.apache.poi.xslf.util.DummyGraphics2d;
 import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.function.ThrowingSupplier;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
 import org.openxmlformats.schemas.drawingml.x2006.main.CTOuterShadowEffect;
 import org.openxmlformats.schemas.presentationml.x2006.main.CTShape;
 
@@ -121,89 +123,87 @@ class TestXSLFBugs {
 
     @Test
     void bug62736() throws Exception {
-        XMLSlideShow ss1 = openSampleDocument("bug62736.pptx");
-
-        assertEquals(1, ss1.getSlides().size());
+        try (XMLSlideShow ss1 = openSampleDocument("bug62736.pptx")) {
+            assertEquals(1, ss1.getSlides().size());
 
-        XSLFSlide slide0 = ss1.getSlides().get(0);
+            XSLFSlide slide0 = ss1.getSlides().get(0);
 
-        assertEquals(slide0.getShapes().size(), 4);
+            assertEquals(slide0.getShapes().size(), 4);
 
-        assertRelation(slide0, "/ppt/slides/slide1.xml", null);
-        assertRelation(slide0, "/ppt/slideLayouts/slideLayout1.xml", "rId1");
-        assertRelation(slide0, "/ppt/media/image1.png", "rId2");
-        assertEquals(slide0.getRelations().size(), 2);
+            assertRelation(slide0, "/ppt/slides/slide1.xml", null);
+            assertRelation(slide0, "/ppt/slideLayouts/slideLayout1.xml", "rId1");
+            assertRelation(slide0, "/ppt/media/image1.png", "rId2");
+            assertEquals(slide0.getRelations().size(), 2);
 
-        List<XSLFPictureShape> pictures = new ArrayList<>();
-        for (XSLFShape shape : slide0.getShapes()) {
-            if (shape instanceof XSLFPictureShape) {
-                pictures.add((XSLFPictureShape) shape);
+            List<XSLFPictureShape> pictures = new ArrayList<>();
+            for (XSLFShape shape : slide0.getShapes()) {
+                if (shape instanceof XSLFPictureShape) {
+                    pictures.add((XSLFPictureShape) shape);
+                }
             }
-        }
 
-        assertEquals(pictures.size(), 2);
-        assertEquals(pictures.get(0).getPictureData().getFileName(), "image1.png");
-        assertEquals(pictures.get(1).getPictureData().getFileName(), "image1.png");
-        // blipId is rId2 of both pictures
+            assertEquals(pictures.size(), 2);
+            assertEquals(pictures.get(0).getPictureData().getFileName(), "image1.png");
+            assertEquals(pictures.get(1).getPictureData().getFileName(), "image1.png");
+            // blipId is rId2 of both pictures
 
-        // remove just the first picture
-        slide0.removeShape(pictures.get(0));
+            // remove just the first picture
+            slide0.removeShape(pictures.get(0));
 
-        assertEquals(slide0.getShapes().size(), 3);
+            assertEquals(slide0.getShapes().size(), 3);
 
-        assertRelation(slide0, "/ppt/slides/slide1.xml", null);
-        assertRelation(slide0, "/ppt/slideLayouts/slideLayout1.xml", "rId1");
-        // the bug is that the following relation is gone
-        assertRelation(slide0, "/ppt/media/image1.png", "rId2");
-        assertEquals(slide0.getRelations().size(), 2);
+            assertRelation(slide0, "/ppt/slides/slide1.xml", null);
+            assertRelation(slide0, "/ppt/slideLayouts/slideLayout1.xml", "rId1");
+            // the bug is that the following relation is gone
+            assertRelation(slide0, "/ppt/media/image1.png", "rId2");
+            assertEquals(slide0.getRelations().size(), 2);
 
-        // Save and re-load
-        XMLSlideShow ss2 = XSLFTestDataSamples.writeOutAndReadBack(ss1);
-        ss1.close();
-        assertEquals(1, ss2.getSlides().size());
+            // Save and re-load
+            try (XMLSlideShow ss2 = writeOutAndReadBack(ss1)) {
+                assertEquals(1, ss2.getSlides().size());
 
-        slide0 = ss2.getSlides().get(0);
+                slide0 = ss2.getSlides().get(0);
 
-        assertRelation(slide0, "/ppt/slides/slide1.xml", null);
-        assertRelation(slide0, "/ppt/slideLayouts/slideLayout1.xml", "rId1");
-        assertRelation(slide0, "/ppt/media/image1.png", "rId2");
-        assertEquals(slide0.getRelations().size(), 2);
+                assertRelation(slide0, "/ppt/slides/slide1.xml", null);
+                assertRelation(slide0, "/ppt/slideLayouts/slideLayout1.xml", "rId1");
+                assertRelation(slide0, "/ppt/media/image1.png", "rId2");
+                assertEquals(slide0.getRelations().size(), 2);
 
-        pictures.clear();
-        for (XSLFShape shape : slide0.getShapes()) {
-            if (shape instanceof XSLFPictureShape) {
-                pictures.add((XSLFPictureShape) shape);
-            }
-        }
+                pictures.clear();
+                for (XSLFShape shape : slide0.getShapes()) {
+                    if (shape instanceof XSLFPictureShape) {
+                        pictures.add((XSLFPictureShape) shape);
+                    }
+                }
 
-        assertEquals(pictures.size(), 1);
-        assertEquals(pictures.get(0).getPictureData().getFileName(), "image1.png");
+                assertEquals(pictures.size(), 1);
+                assertEquals(pictures.get(0).getPictureData().getFileName(), "image1.png");
 
-        slide0.removeShape(pictures.get(0));
+                slide0.removeShape(pictures.get(0));
 
-        assertEquals(slide0.getShapes().size(), 2);
+                assertEquals(slide0.getShapes().size(), 2);
 
-        assertRelation(slide0, "/ppt/slides/slide1.xml", null);
-        assertRelation(slide0, "/ppt/slideLayouts/slideLayout1.xml", "rId1");
-        assertNull(slide0.getRelationById("rId2"));
-        assertEquals(slide0.getRelations().size(), 1);
+                assertRelation(slide0, "/ppt/slides/slide1.xml", null);
+                assertRelation(slide0, "/ppt/slideLayouts/slideLayout1.xml", "rId1");
+                assertNull(slide0.getRelationById("rId2"));
+                assertEquals(slide0.getRelations().size(), 1);
 
-        // Save and re-load
-        XMLSlideShow ss3 = XSLFTestDataSamples.writeOutAndReadBack(ss2);
-        ss2.close();
-        assertEquals(1, ss3.getSlides().size());
+                // Save and re-load
+                try (XMLSlideShow ss3 = writeOutAndReadBack(ss2)) {
+                    assertEquals(1, ss3.getSlides().size());
 
-        slide0 = ss3.getSlides().get(0);
+                    slide0 = ss3.getSlides().get(0);
 
-        assertRelation(slide0, "/ppt/slides/slide1.xml", null);
-        assertRelation(slide0, "/ppt/slideLayouts/slideLayout1.xml", "rId1");
-        assertEquals(slide0.getShapes().size(), 2);
-        ss3.close();
+                    assertRelation(slide0, "/ppt/slides/slide1.xml", null);
+                    assertRelation(slide0, "/ppt/slideLayouts/slideLayout1.xml", "rId1");
+                    assertEquals(slide0.getShapes().size(), 2);
+                }
+            }
+        }
     }
 
     @Test
     void bug61589() throws IOException {
-        ByteArrayOutputStream bos = new ByteArrayOutputStream();
         try (XMLSlideShow src = new XMLSlideShow();
              XMLSlideShow dest = new XMLSlideShow()) {
             XSLFSlide slide = src.createSlide();
@@ -229,71 +229,65 @@ class TestXSLFBugs {
             dest.createSlide().importContent(slide);
             dest.createSlide().importContent(slide2);
 
-            dest.write(bos);
+            try (XMLSlideShow ppt3 = writeOutAndReadBack(dest)) {
+                XSLFSlide slide3 = ppt3.getSlides().get(0);
+                XSLFTextBox shape3 = (XSLFTextBox) slide3.getShapes().get(0);
+                XSLFTextParagraph p3 = shape3.getTextParagraphs().get(1);
+                XSLFHyperlink h1 = p3.getTextRuns().get(0).getHyperlink();
+                assertNotNull(h1);
+                assertEquals("https://poi.apache.org", h1.getAddress());
+                XSLFHyperlink h2 = p3.getTextRuns().get(2).getHyperlink();
+                assertNotNull(h2);
+                // relative url will be resolved to an absolute url, therefore this doesn't equals to "slide2.xml"
+                assertEquals("/ppt/slides/slide2.xml", h2.getAddress());
+                RelationPart sldRef = slide3.getRelationPartById(h2.getXmlObject().getId());
+                assertTrue(sldRef.getDocumentPart() instanceof XSLFSlide);
+            }
         }
 
-        try (XMLSlideShow ppt = new XMLSlideShow(new ByteArrayInputStream(bos.toByteArray()))) {
-            XSLFSlide slide = ppt.getSlides().get(0);
-            XSLFTextBox shape = (XSLFTextBox) slide.getShapes().get(0);
-            XSLFTextParagraph p = shape.getTextParagraphs().get(1);
-            XSLFHyperlink h1 = p.getTextRuns().get(0).getHyperlink();
-            assertNotNull(h1);
-            assertEquals("https://poi.apache.org", h1.getAddress());
-            XSLFHyperlink h2 = p.getTextRuns().get(2).getHyperlink();
-            assertNotNull(h2);
-            // relative url will be resolved to an absolute url, therefore this doesn't equals to "slide2.xml"
-            assertEquals("/ppt/slides/slide2.xml", h2.getAddress());
-            RelationPart sldRef = slide.getRelationPartById(h2.getXmlObject().getId());
-            assertTrue(sldRef.getDocumentPart() instanceof XSLFSlide);
-        }
     }
 
     @Test
     void bug62587() throws IOException {
-        ByteArrayOutputStream bos = new ByteArrayOutputStream();
-        try (XMLSlideShow ppt = new XMLSlideShow()) {
-            Slide<?, ?> slide = ppt.createSlide();
-            XSLFPictureData pd = ppt.addPicture(slTests.getFile("wrench.emf"), PictureType.EMF);
-            PictureShape<?, ?> ps = slide.createPicture(pd);
-            ps.setAnchor(new Rectangle2D.Double(100, 100, 100, 100));
-            ppt.write(bos);
-        }
-
         Object[][] pics = {
             {"santa.wmf", PictureType.WMF, XSLFRelation.IMAGE_WMF},
             {"tomcat.png", PictureType.PNG, XSLFRelation.IMAGE_PNG},
             {"clock.jpg", PictureType.JPEG, XSLFRelation.IMAGE_JPEG}
         };
 
-        try (XMLSlideShow ppt = new XMLSlideShow(new ByteArrayInputStream(bos.toByteArray()))) {
-            XSLFSlide s1 = ppt.getSlides().get(0);
-
-            for (Object[] p : pics) {
-                XSLFSlide s2 = ppt.createSlide();
-                s2.importContent(s1);
-
-                XSLFPictureData pd = ppt.addPicture(slTests.getFile((String) p[0]), (PictureType) p[1]);
-                XSLFPictureShape ps = (XSLFPictureShape) s2.getShapes().get(0);
-                Rectangle2D anchor = ps.getAnchor();
-                s2.removeShape(ps);
-                ps = s2.createPicture(pd);
-                ps.setAnchor(anchor);
-            }
-
-            bos.reset();
-            ppt.write(bos);
-        }
+        try (XMLSlideShow ppt1 = new XMLSlideShow()) {
+            Slide<?, ?> slide = ppt1.createSlide();
+            XSLFPictureData pd1 = ppt1.addPicture(slTests.getFile("wrench.emf"), PictureType.EMF);
+            PictureShape<?, ?> ps1 = slide.createPicture(pd1);
+            ps1.setAnchor(new Rectangle2D.Double(100, 100, 100, 100));
+
+            try (XMLSlideShow ppt2 = writeOutAndReadBack(ppt1)) {
+                XSLFSlide s1 = ppt2.getSlides().get(0);
+
+                for (Object[] p : pics) {
+                    XSLFSlide s2 = ppt2.createSlide();
+                    s2.importContent(s1);
+
+                    XSLFPictureData pd2 = ppt2.addPicture(slTests.getFile((String) p[0]), (PictureType) p[1]);
+                    XSLFPictureShape ps2 = (XSLFPictureShape) s2.getShapes().get(0);
+                    Rectangle2D anchor2 = ps2.getAnchor();
+                    s2.removeShape(ps2);
+                    ps2 = s2.createPicture(pd2);
+                    ps2.setAnchor(anchor2);
+                }
 
-        try (XMLSlideShow ppt = new XMLSlideShow(new ByteArrayInputStream(bos.toByteArray()))) {
-            for (XSLFSlide sl : ppt.getSlides()) {
-                List<RelationPart> rels = sl.getRelationParts();
-                assertEquals(2, rels.size());
-                RelationPart rel0 = rels.get(0);
-                assertEquals("rId1", rel0.getRelationship().getId());
-                assertEquals(XSLFRelation.SLIDE_LAYOUT.getRelation(), rel0.getRelationship().getRelationshipType());
-                RelationPart rel1 = rels.get(1);
-                assertEquals("rId2", rel1.getRelationship().getId());
-                assertEquals(XSLFRelation.IMAGES.getRelation(), rel1.getRelationship().getRelationshipType());
+                try (XMLSlideShow ppt3 = writeOutAndReadBack(ppt2)) {
+                    for (XSLFSlide sl : ppt3.getSlides()) {
+                        List<RelationPart> rels = sl.getRelationParts();
+                        assertEquals(2, rels.size());
+                        RelationPart rel0 = rels.get(0);
+                        assertEquals("rId1", rel0.getRelationship().getId());
+                        assertEquals(XSLFRelation.SLIDE_LAYOUT.getRelation(), rel0.getRelationship().getRelationshipType());
+                        RelationPart rel1 = rels.get(1);
+                        assertEquals("rId2", rel1.getRelationship().getId());
+                        assertEquals(XSLFRelation.IMAGES.getRelation(), rel1.getRelationship().getRelationshipType());
+                    }
+                }
             }
         }
     }
@@ -301,78 +295,73 @@ class TestXSLFBugs {
 
     @Test
     void bug60499() throws IOException, InvalidFormatException {
-        InputStream is = slTests.openResourceAsStream("bug60499.pptx");
-        byte[] buf = IOUtils.toByteArray(is);
-        is.close();
-
         PackagePartName ppn = PackagingURIHelper.createPartName("/ppt/media/image1.png");
 
-        XMLSlideShow ppt1 = new XMLSlideShow(new ByteArrayInputStream(buf));
-        XSLFSlide slide1 = ppt1.getSlides().get(0);
-
-        Optional<XSLFShape> shapeToDelete1 =
-            slide1.getShapes().stream().filter(s -> s instanceof XSLFPictureShape).findFirst();
-
-        assertTrue(shapeToDelete1.isPresent());
-        slide1.removeShape(shapeToDelete1.get());
-        assertTrue(slide1.getRelationParts().stream()
-            .allMatch(rp -> "rId1,rId3".contains(rp.getRelationship().getId())));
-
-        assertNotNull(ppt1.getPackage().getPart(ppn));
-        ppt1.close();
-
-        XMLSlideShow ppt2 = new XMLSlideShow(new ByteArrayInputStream(buf));
-        XSLFSlide slide2 = ppt2.getSlides().get(0);
-
-        Optional<XSLFShape> shapeToDelete2 =
-            slide2.getShapes().stream().filter(s -> s instanceof XSLFPictureShape).skip(1).findFirst();
-        assertTrue(shapeToDelete2.isPresent());
-        slide2.removeShape(shapeToDelete2.get());
-        assertTrue(slide2.getRelationParts().stream()
-            .allMatch(rp -> "rId1,rId2".contains(rp.getRelationship().getId())));
-        assertNotNull(ppt2.getPackage().getPart(ppn));
-        ppt2.close();
-
-        XMLSlideShow ppt3 = new XMLSlideShow(new ByteArrayInputStream(buf));
-        XSLFSlide slide3 = ppt3.getSlides().get(0);
-        slide3.getShapes().stream()
-            .filter(s -> s instanceof XSLFPictureShape)
-            .collect(Collectors.toList())
-            .forEach(slide3::removeShape);
-        assertNull(ppt3.getPackage().getPart(ppn));
-        ppt3.close();
+        try (XMLSlideShow ppt1 = openSampleDocument("bug60499.pptx")) {
+            XSLFSlide slide1 = ppt1.getSlides().get(0);
+
+            Optional<XSLFShape> shapeToDelete1 =
+                slide1.getShapes().stream().filter(s -> s instanceof XSLFPictureShape).findFirst();
+
+            assertTrue(shapeToDelete1.isPresent());
+            slide1.removeShape(shapeToDelete1.get());
+            assertTrue(slide1.getRelationParts().stream()
+                .allMatch(rp -> "rId1,rId3".contains(rp.getRelationship().getId())));
+
+            assertNotNull(ppt1.getPackage().getPart(ppn));
+        }
+
+        try (XMLSlideShow ppt2 = openSampleDocument("bug60499.pptx")) {
+            XSLFSlide slide2 = ppt2.getSlides().get(0);
+            Optional<XSLFShape> shapeToDelete2 =
+                slide2.getShapes().stream().filter(s -> s instanceof XSLFPictureShape).skip(1).findFirst();
+            assertTrue(shapeToDelete2.isPresent());
+            slide2.removeShape(shapeToDelete2.get());
+            assertTrue(slide2.getRelationParts().stream()
+                .allMatch(rp -> "rId1,rId2".contains(rp.getRelationship().getId())));
+            assertNotNull(ppt2.getPackage().getPart(ppn));
+        }
+
+        try (XMLSlideShow ppt3 = openSampleDocument("bug60499.pptx")) {
+            XSLFSlide slide3 = ppt3.getSlides().get(0);
+            slide3.getShapes().stream()
+                .filter(s -> s instanceof XSLFPictureShape)
+                .collect(Collectors.toList())
+                .forEach(slide3::removeShape);
+            assertNull(ppt3.getPackage().getPart(ppn));
+        }
     }
 
     @Test
     void bug51187() throws Exception {
-        XMLSlideShow ss1 = openSampleDocument("51187.pptx");
-
-        assertEquals(1, ss1.getSlides().size());
-
-        // Check the relations on it
-        // Note - rId3 is a self reference
-        XSLFSlide slide0 = ss1.getSlides().get(0);
-
-        assertRelation(slide0, "/ppt/slides/slide1.xml", null);
-        assertRelation(slide0, "/ppt/slideLayouts/slideLayout12.xml", "rId1");
-        assertRelation(slide0, "/ppt/notesSlides/notesSlide1.xml", "rId2");
-        assertRelation(slide0, "/ppt/slides/slide1.xml", "rId3");
-        assertRelation(slide0, "/ppt/media/image1.png", "rId4");
-
-        // Save and re-load
-        XMLSlideShow ss2 = XSLFTestDataSamples.writeOutAndReadBack(ss1);
-        ss1.close();
-        assertEquals(1, ss2.getSlides().size());
-
-        slide0 = ss2.getSlides().get(0);
-        assertRelation(slide0, "/ppt/slides/slide1.xml", null);
-        assertRelation(slide0, "/ppt/slideLayouts/slideLayout12.xml", "rId1");
-        assertRelation(slide0, "/ppt/notesSlides/notesSlide1.xml", "rId2");
-        // TODO Fix this
-        assertRelation(slide0, "/ppt/slides/slide1.xml", "rId3");
-        assertRelation(slide0, "/ppt/media/image1.png", "rId4");
-
-        ss2.close();
+        try (XMLSlideShow ss1 = openSampleDocument("51187.pptx")) {
+
+            assertEquals(1, ss1.getSlides().size());
+
+            // Check the relations on it
+            // Note - rId3 is a self reference
+            XSLFSlide slide0 = ss1.getSlides().get(0);
+
+            assertRelation(slide0, "/ppt/slides/slide1.xml", null);
+            assertRelation(slide0, "/ppt/slideLayouts/slideLayout12.xml", "rId1");
+            assertRelation(slide0, "/ppt/notesSlides/notesSlide1.xml", "rId2");
+            assertRelation(slide0, "/ppt/slides/slide1.xml", "rId3");
+            assertRelation(slide0, "/ppt/media/image1.png", "rId4");
+
+            // Save and re-load
+            try (XMLSlideShow ss2 = writeOutAndReadBack(ss1)) {
+                assertEquals(1, ss2.getSlides().size());
+
+                slide0 = ss2.getSlides().get(0);
+                assertRelation(slide0, "/ppt/slides/slide1.xml", null);
+                assertRelation(slide0, "/ppt/slideLayouts/slideLayout12.xml", "rId1");
+                assertRelation(slide0, "/ppt/notesSlides/notesSlide1.xml", "rId2");
+                // TODO Fix this
+                assertRelation(slide0, "/ppt/slides/slide1.xml", "rId3");
+                assertRelation(slide0, "/ppt/media/image1.png", "rId4");
+
+            }
+        }
     }
 
     private static void assertRelation(XSLFSlide slide, String exp, String rId) {
@@ -386,41 +375,40 @@ class TestXSLFBugs {
      */
     @Test
     void tika705() throws Exception {
-        XMLSlideShow ss = openSampleDocument("with_japanese.pptx");
-
-        // Should have one slide
-        assertEquals(1, ss.getSlides().size());
-        XSLFSlide slide = ss.getSlides().get(0);
-
-        // Check the relations from this
-        Collection<RelationPart> rels = slide.getRelationParts();
-
-        // Should have 6 relations:
-        //   1 external hyperlink (skipped from list)
-        //   4 internal hyperlinks
-        //   1 slide layout
-        assertEquals(5, rels.size());
-        int layouts = 0;
-        int hyperlinks = 0;
-        for (RelationPart p : rels) {
-            if (p.getRelationship().getRelationshipType().equals(XSLFRelation.HYPERLINK.getRelation())) {
-                hyperlinks++;
-            } else if (p.getDocumentPart() instanceof XSLFSlideLayout) {
-                layouts++;
+        try (XMLSlideShow ss = openSampleDocument("with_japanese.pptx")) {
+            // Should have one slide
+            assertEquals(1, ss.getSlides().size());
+            XSLFSlide slide = ss.getSlides().get(0);
+
+            // Check the relations from this
+            Collection<RelationPart> rels = slide.getRelationParts();
+
+            // Should have 6 relations:
+            //   1 external hyperlink (skipped from list)
+            //   4 internal hyperlinks
+            //   1 slide layout
+            assertEquals(5, rels.size());
+            int layouts = 0;
+            int hyperlinks = 0;
+            for (RelationPart p : rels) {
+                if (p.getRelationship().getRelationshipType().equals(XSLFRelation.HYPERLINK.getRelation())) {
+                    hyperlinks++;
+                } else if (p.getDocumentPart() instanceof XSLFSlideLayout) {
+                    layouts++;
+                }
             }
-        }
-        assertEquals(1, layouts);
-        assertEquals(4, hyperlinks);
-
-        // Hyperlinks should all be to #_ftn1 or #ftnref1
-        for (RelationPart p : rels) {
-            if (p.getRelationship().getRelationshipType().equals(XSLFRelation.HYPERLINK.getRelation())) {
-                URI target = p.getRelationship().getTargetURI();
-                String frag = target.getFragment();
-                assertTrue(frag.equals("_ftn1") || frag.equals("_ftnref1"), "Invalid target " + frag + " on " + target);
+            assertEquals(1, layouts);
+            assertEquals(4, hyperlinks);
+
+            // Hyperlinks should all be to #_ftn1 or #ftnref1
+            for (RelationPart p : rels) {
+                if (p.getRelationship().getRelationshipType().equals(XSLFRelation.HYPERLINK.getRelation())) {
+                    URI target = p.getRelationship().getTargetURI();
+                    String frag = target.getFragment();
+                    assertTrue(frag.equals("_ftn1") || frag.equals("_ftnref1"), "Invalid target " + frag + " on " + target);
+                }
             }
         }
-        ss.close();
     }
 
     /**
@@ -459,34 +447,34 @@ class TestXSLFBugs {
      */
     @Test
     void bug56812() throws Exception {
-        XMLSlideShow ppt = openSampleDocument("56812.pptx");
-
-        int internalPictures = 0;
-        int externalPictures = 0;
-        for (XSLFSlide slide : ppt.getSlides()) {
-            for (XSLFShape shape : slide.getShapes()) {
-                assertNotNull(shape);
-
-                if (shape instanceof XSLFPictureShape) {
-                    XSLFPictureShape picture = (XSLFPictureShape) shape;
-                    if (picture.isExternalLinkedPicture()) {
-                        externalPictures++;
-
-                        assertNotNull(picture.getPictureLink());
-                    } else {
-                        internalPictures++;
-
-                        XSLFPictureData data = picture.getPictureData();
-                        assertNotNull(data);
-                        assertNotNull(data.getFileName());
+        try (XMLSlideShow ppt = openSampleDocument("56812.pptx")) {
+
+            int internalPictures = 0;
+            int externalPictures = 0;
+            for (XSLFSlide slide : ppt.getSlides()) {
+                for (XSLFShape shape : slide.getShapes()) {
+                    assertNotNull(shape);
+
+                    if (shape instanceof XSLFPictureShape) {
+                        XSLFPictureShape picture = (XSLFPictureShape) shape;
+                        if (picture.isExternalLinkedPicture()) {
+                            externalPictures++;
+
+                            assertNotNull(picture.getPictureLink());
+                        } else {
+                            internalPictures++;
+
+                            XSLFPictureData data = picture.getPictureData();
+                            assertNotNull(data);
+                            assertNotNull(data.getFileName());
+                        }
                     }
                 }
             }
-        }
 
-        assertEquals(2, internalPictures);
-        assertEquals(1, externalPictures);
-        ppt.close();
+            assertEquals(2, internalPictures);
+            assertEquals(1, externalPictures);
+        }
     }
 
     private String getSlideText(XMLSlideShow ppt, XSLFSlide slide) throws IOException {
@@ -502,29 +490,29 @@ class TestXSLFBugs {
 
     @Test
     void bug57250() throws Exception {
-        XMLSlideShow ss = new XMLSlideShow();
-        for (String s : new String[]{"Slide1", "Slide2"}) {
-            ss.createSlide().createTextBox().setText(s);
-        }
-        validateSlides(ss, false, "Slide1", "Slide2");
+        try (XMLSlideShow ss = new XMLSlideShow()) {
+            for (String s : new String[]{"Slide1", "Slide2"}) {
+                ss.createSlide().createTextBox().setText(s);
+            }
+            validateSlides(ss, false, "Slide1", "Slide2");
 
-        XSLFSlide slide = ss.createSlide();
-        slide.createTextBox().setText("New slide");
-        validateSlides(ss, true, "Slide1", "Slide2", "New slide");
+            XSLFSlide slide = ss.createSlide();
+            slide.createTextBox().setText("New slide");
+            validateSlides(ss, true, "Slide1", "Slide2", "New slide");
 
-        // Move backward
-        ss.setSlideOrder(slide, 0);
-        validateSlides(ss, true, "New slide", "Slide1", "Slide2");
+            // Move backward
+            ss.setSlideOrder(slide, 0);
+            validateSlides(ss, true, "New slide", "Slide1", "Slide2");
 
-        // Move forward
-        ss.setSlideOrder(slide, 1);
-        validateSlides(ss, true, "Slide1", "New slide", "Slide2");
+            // Move forward
+            ss.setSlideOrder(slide, 1);
+            validateSlides(ss, true, "Slide1", "New slide", "Slide2");
 
-        // Move to end
-        ss.setSlideOrder(slide, 0);
-        ss.setSlideOrder(slide, 2);
-        validateSlides(ss, true, "Slide1", "Slide2", "New slide");
-        ss.close();
+            // Move to end
+            ss.setSlideOrder(slide, 0);
+            ss.setSlideOrder(slide, 2);
+            validateSlides(ss, true, "Slide1", "Slide2", "New slide");
+        }
     }
 
     /**
@@ -533,89 +521,88 @@ class TestXSLFBugs {
      */
     @Test
     void test57552() throws Exception {
-        XMLSlideShow ss = new XMLSlideShow();
-        for (String s : new String[]{"Slide1", "Slide2"}) {
-            ss.createSlide().createTextBox().setText(s);
-        }
+        try (XMLSlideShow ss = new XMLSlideShow()) {
+            for (String s : new String[]{"Slide1", "Slide2"}) {
+                ss.createSlide().createTextBox().setText(s);
+            }
 
-        // Slide starts with just layout relation
-        XSLFSlide slide = ss.getSlides().get(0);
-        assertEquals(0, ss.getPictureData().size());
-        assertEquals(1, slide.getShapes().size());
+            // Slide starts with just layout relation
+            XSLFSlide slide = ss.getSlides().get(0);
+            assertEquals(0, ss.getPictureData().size());
+            assertEquals(1, slide.getShapes().size());
 
-        assertEquals(1, slide.getRelations().size());
+            assertEquals(1, slide.getRelations().size());
 
-        final XSLFRelation expected = XSLFRelation.SLIDE_LAYOUT;
-        final POIXMLDocumentPart relation = slide.getRelations().get(0);
+            final XSLFRelation expected = XSLFRelation.SLIDE_LAYOUT;
+            final POIXMLDocumentPart relation = slide.getRelations().get(0);
 
-        assertEquals(expected.getContentType(), relation.getPackagePart().getContentType());
-        assertEquals(expected.getFileName(expected.getFileNameIndex(relation)), relation.getPackagePart().getPartName().getName());
+            assertEquals(expected.getContentType(), relation.getPackagePart().getContentType());
+            assertEquals(expected.getFileName(expected.getFileNameIndex(relation)), relation.getPackagePart().getPartName().getName());
 
-        // Some dummy pictures
-        byte[][] pics = new byte[15][3];
-        for (int i = 0; i < pics.length; i++) {
-            Arrays.fill(pics[i], (byte) i);
-        }
-
-        // Add a few pictures
-        addPictures(ss, slide, pics, 0, 10);
+            // Some dummy pictures
+            byte[][] pics = new byte[15][3];
+            for (int i = 0; i < pics.length; i++) {
+                Arrays.fill(pics[i], (byte) i);
+            }
 
-        // Re-fetch the pictures and check
-        for (int i = 0; i < 10; i++) {
-            XSLFPictureShape shape = (XSLFPictureShape) slide.getShapes().get(i + 1);
-            assertNotNull(shape.getPictureData());
-            assertArrayEquals(pics[i], shape.getPictureData().getData());
-        }
+            // Add a few pictures
+            addPictures(ss, slide, pics, 0, 10);
 
-        // Add past 10
-        addPictures(ss, slide, pics, 10, 15);
+            // Re-fetch the pictures and check
+            for (int i = 0; i < 10; i++) {
+                XSLFPictureShape shape = (XSLFPictureShape) slide.getShapes().get(i + 1);
+                assertNotNull(shape.getPictureData());
+                assertArrayEquals(pics[i], shape.getPictureData().getData());
+            }
 
-        // Check all pictures
-        for (int i = 0; i < 15; i++) {
-            XSLFPictureShape shape = (XSLFPictureShape) slide.getShapes().get(i + 1);
-            assertNotNull(shape.getPictureData());
-            assertArrayEquals(pics[i], shape.getPictureData().getData());
-        }
+            // Add past 10
+            addPictures(ss, slide, pics, 10, 15);
 
-        // Add a duplicate, check the right one is picked
-        XSLFPictureData data = ss.addPicture(pics[3], PictureType.JPEG);
-        assertEquals(3, data.getIndex());
-        assertEquals(15, ss.getPictureData().size());
+            // Check all pictures
+            for (int i = 0; i < 15; i++) {
+                XSLFPictureShape shape = (XSLFPictureShape) slide.getShapes().get(i + 1);
+                assertNotNull(shape.getPictureData());
+                assertArrayEquals(pics[i], shape.getPictureData().getData());
+            }
 
-        XSLFPictureShape shape = slide.createPicture(data);
-        assertNotNull(shape.getPictureData());
-        assertArrayEquals(pics[3], shape.getPictureData().getData());
-        assertEquals(17, slide.getShapes().size());
+            // Add a duplicate, check the right one is picked
+            XSLFPictureData data = ss.addPicture(pics[3], PictureType.JPEG);
+            assertEquals(3, data.getIndex());
+            assertEquals(15, ss.getPictureData().size());
 
+            XSLFPictureShape shape = slide.createPicture(data);
+            assertNotNull(shape.getPictureData());
+            assertArrayEquals(pics[3], shape.getPictureData().getData());
+            assertEquals(17, slide.getShapes().size());
 
-        // Save and re-load
-        XMLSlideShow ss2 = XSLFTestDataSamples.writeOutAndReadBack(ss);
-        slide = ss2.getSlides().get(0);
 
-        // Check the 15 individual ones added
-        for (int i = 0; i < 15; i++) {
-            shape = (XSLFPictureShape) slide.getShapes().get(i + 1);
-            assertNotNull(shape.getPictureData());
-            assertArrayEquals(pics[i], shape.getPictureData().getData());
-        }
+            // Save and re-load
+            try (XMLSlideShow ss2 = writeOutAndReadBack(ss)) {
+                slide = ss2.getSlides().get(0);
 
-        // Check the duplicate
-        shape = (XSLFPictureShape) slide.getShapes().get(16);
-        assertNotNull(shape.getPictureData());
-        assertArrayEquals(pics[3], shape.getPictureData().getData());
+                // Check the 15 individual ones added
+                for (int i = 0; i < 15; i++) {
+                    shape = (XSLFPictureShape) slide.getShapes().get(i + 1);
+                    assertNotNull(shape.getPictureData());
+                    assertArrayEquals(pics[i], shape.getPictureData().getData());
+                }
 
-        // Add another duplicate
-        data = ss2.addPicture(pics[5], PictureType.JPEG);
-        assertEquals(5, data.getIndex());
-        assertEquals(15, ss2.getPictureData().size());
+                // Check the duplicate
+                shape = (XSLFPictureShape) slide.getShapes().get(16);
+                assertNotNull(shape.getPictureData());
+                assertArrayEquals(pics[3], shape.getPictureData().getData());
 
-        shape = slide.createPicture(data);
-        assertNotNull(shape.getPictureData());
-        assertArrayEquals(pics[5], shape.getPictureData().getData());
-        assertEquals(18, slide.getShapes().size());
+                // Add another duplicate
+                data = ss2.addPicture(pics[5], PictureType.JPEG);
+                assertEquals(5, data.getIndex());
+                assertEquals(15, ss2.getPictureData().size());
 
-        ss2.close();
-        ss.close();
+                shape = slide.createPicture(data);
+                assertNotNull(shape.getPictureData());
+                assertArrayEquals(pics[5], shape.getPictureData().getData());
+                assertEquals(18, slide.getShapes().size());
+            }
+        }
     }
 
     private void addPictures(XMLSlideShow ss, XSLFSlide slide, byte[][] pics, int start, int end) {
@@ -633,9 +620,9 @@ class TestXSLFBugs {
 
     private void validateSlides(XMLSlideShow ss, boolean saveAndReload, String... slideTexts) throws IOException {
         if (saveAndReload) {
-            XMLSlideShow ss2 = XSLFTestDataSamples.writeOutAndReadBack(ss);
-            validateSlides(ss, slideTexts);
-            ss2.close();
+            try (XMLSlideShow ss2 = writeOutAndReadBack(ss)) {
+                validateSlides(ss2, slideTexts);
+            }
         } else {
             validateSlides(ss, slideTexts);
         }
@@ -652,69 +639,57 @@ class TestXSLFBugs {
 
     @Test
     void bug58205() throws IOException {
-        XMLSlideShow ss = openSampleDocument("themes.pptx");
-
-        int i = 1;
-        for (XSLFSlideMaster sm : ss.getSlideMasters()) {
-            assertEquals("rId" + (i++), ss.getRelationId(sm));
+        try (XMLSlideShow ss = openSampleDocument("themes.pptx")) {
+            int i = 1;
+            for (XSLFSlideMaster sm : ss.getSlideMasters()) {
+                assertEquals("rId" + (i++), ss.getRelationId(sm));
+            }
         }
-
-        ss.close();
     }
 
-    @Test
-    void bug55791a() throws IOException {
-        XMLSlideShow ppt = openSampleDocument("45541_Footer.pptx");
-        removeAndCreateSlide(ppt);
-        ppt.close();
-    }
-
-    @Test
-    void bug55791b() throws IOException {
-        XMLSlideShow ppt = openSampleDocument("SampleShow.pptx");
-        removeAndCreateSlide(ppt);
-        ppt.close();
-    }
-
-    private void removeAndCreateSlide(XMLSlideShow ppt) {
-        assertTrue(ppt.getSlides().size() > 1);
-        ppt.removeSlide(1);
-        assertNotNull(ppt.createSlide());
+    @ParameterizedTest
+    @ValueSource(strings = {"45541_Footer.pptx", "SampleShow.pptx"})
+    void bug55791(String fileName) throws IOException {
+        try (XMLSlideShow ppt = openSampleDocument(fileName)) {
+            assertTrue(ppt.getSlides().size() > 1);
+            ppt.removeSlide(1);
+            assertNotNull(ppt.createSlide());
+        }
     }
 
     @Test
     void blibFillAlternateContent() throws IOException {
-        XMLSlideShow ppt = openSampleDocument("2411-Performance_Up.pptx");
-        XSLFPictureShape ps = (XSLFPictureShape) ppt.getSlides().get(4).getShapes().get(0);
-        assertNotNull(ps.getPictureData());
-        ppt.close();
+        try (XMLSlideShow ppt = openSampleDocument("2411-Performance_Up.pptx")) {
+            XSLFPictureShape ps = (XSLFPictureShape) ppt.getSlides().get(4).getShapes().get(0);
+            assertNotNull(ps.getPictureData());
+        }
     }
 
     @Test
     void bug59434() throws IOException {
         String url1 = "https://poi.apache.org/changes.html";
         String url2 = "https://poi.apache.org/faq.html";
-        XMLSlideShow ppt1 = new XMLSlideShow();
-        PictureData pd1 = ppt1.addPicture(slTests.readFile("tomcat.png"), PictureType.PNG);
-        PictureData pd2 = ppt1.addPicture(slTests.readFile("santa.wmf"), PictureType.WMF);
-        XSLFSlide slide = ppt1.createSlide();
-        XSLFPictureShape ps1 = slide.createPicture(pd1);
-        ps1.setAnchor(new Rectangle2D.Double(20, 20, 100, 100));
-        XSLFHyperlink hl1 = ps1.createHyperlink();
-        hl1.linkToUrl(url1);
-        XSLFPictureShape ps2 = slide.createPicture(pd2);
-        ps2.setAnchor(new Rectangle2D.Double(120, 120, 100, 100));
-        XSLFHyperlink hl2 = ps2.createHyperlink();
-        hl2.linkToUrl(url2);
-        XMLSlideShow ppt2 = XSLFTestDataSamples.writeOutAndReadBack(ppt1);
-        ppt1.close();
-        slide = ppt2.getSlides().get(0);
-        ps1 = (XSLFPictureShape) slide.getShapes().get(0);
-        ps2 = (XSLFPictureShape) slide.getShapes().get(1);
-        assertEquals(url1, ps1.getHyperlink().getAddress());
-        assertEquals(url2, ps2.getHyperlink().getAddress());
-
-        ppt2.close();
+        try (XMLSlideShow ppt1 = new XMLSlideShow()) {
+            PictureData pd1 = ppt1.addPicture(slTests.readFile("tomcat.png"), PictureType.PNG);
+            PictureData pd2 = ppt1.addPicture(slTests.readFile("santa.wmf"), PictureType.WMF);
+            XSLFSlide slide = ppt1.createSlide();
+            XSLFPictureShape ps1 = slide.createPicture(pd1);
+            ps1.setAnchor(new Rectangle2D.Double(20, 20, 100, 100));
+            XSLFHyperlink hl1 = ps1.createHyperlink();
+            hl1.linkToUrl(url1);
+            XSLFPictureShape ps2 = slide.createPicture(pd2);
+            ps2.setAnchor(new Rectangle2D.Double(120, 120, 100, 100));
+            XSLFHyperlink hl2 = ps2.createHyperlink();
+            hl2.linkToUrl(url2);
+
+            try (XMLSlideShow ppt2 = writeOutAndReadBack(ppt1)) {
+                slide = ppt2.getSlides().get(0);
+                ps1 = (XSLFPictureShape) slide.getShapes().get(0);
+                ps2 = (XSLFPictureShape) slide.getShapes().get(1);
+                assertEquals(url1, ps1.getHyperlink().getAddress());
+                assertEquals(url2, ps2.getHyperlink().getAddress());
+            }
+        }
     }
 
     @Test
@@ -723,27 +698,27 @@ class TestXSLFBugs {
         Color lineColor = new Color(25.3f / 255f, 1f, 0f, 0.4f);
         Color textColor = new Color(1f, 1f, 0f, 0.6f);
 
-        XMLSlideShow ppt1 = new XMLSlideShow();
-        XSLFSlide sl = ppt1.createSlide();
-        XSLFAutoShape as = sl.createAutoShape();
-        as.setShapeType(ShapeType.STAR_10);
-        as.setAnchor(new Rectangle2D.Double(100, 100, 300, 300));
-        as.setFillColor(fillColor);
-        as.setLineColor(lineColor);
-        as.setText("Alpha");
-        as.setVerticalAlignment(VerticalAlignment.MIDDLE);
-        as.setHorizontalCentered(true);
-        XSLFTextRun tr = as.getTextParagraphs().get(0).getTextRuns().get(0);
-        tr.setFontSize(32d);
-        tr.setFontColor(textColor);
-        XMLSlideShow ppt2 = XSLFTestDataSamples.writeOutAndReadBack(ppt1);
-        ppt1.close();
-        sl = ppt2.getSlides().get(0);
-        as = (XSLFAutoShape) sl.getShapes().get(0);
-        checkColor(fillColor, as.getFillStyle().getPaint());
-        checkColor(lineColor, as.getStrokeStyle().getPaint());
-        checkColor(textColor, as.getTextParagraphs().get(0).getTextRuns().get(0).getFontColor());
-        ppt2.close();
+        try (XMLSlideShow ppt1 = new XMLSlideShow()) {
+            XSLFSlide sl = ppt1.createSlide();
+            XSLFAutoShape as = sl.createAutoShape();
+            as.setShapeType(ShapeType.STAR_10);
+            as.setAnchor(new Rectangle2D.Double(100, 100, 300, 300));
+            as.setFillColor(fillColor);
+            as.setLineColor(lineColor);
+            as.setText("Alpha");
+            as.setVerticalAlignment(VerticalAlignment.MIDDLE);
+            as.setHorizontalCentered(true);
+            XSLFTextRun tr = as.getTextParagraphs().get(0).getTextRuns().get(0);
+            tr.setFontSize(32d);
+            tr.setFontColor(textColor);
+            try (XMLSlideShow ppt2 = writeOutAndReadBack(ppt1)) {
+                sl = ppt2.getSlides().get(0);
+                as = (XSLFAutoShape) sl.getShapes().get(0);
+                checkColor(fillColor, as.getFillStyle().getPaint());
+                checkColor(lineColor, as.getStrokeStyle().getPaint());
+                checkColor(textColor, as.getTextParagraphs().get(0).getTextRuns().get(0).getFontColor());
+            }
+        }
     }
 
     private static void checkColor(Color expected, PaintStyle actualStyle) {
@@ -757,64 +732,60 @@ class TestXSLFBugs {
 
     @Test
     void bug55714() throws IOException {
-        XMLSlideShow srcPptx = openSampleDocument("pptx2svg.pptx");
-        XMLSlideShow newPptx = new XMLSlideShow();
-        XSLFSlide srcSlide = srcPptx.getSlides().get(0);
-        XSLFSlide newSlide = newPptx.createSlide();
-
-        XSLFSlideLayout srcSlideLayout = srcSlide.getSlideLayout();
-        XSLFSlideLayout newSlideLayout = newSlide.getSlideLayout();
-        newSlideLayout.importContent(srcSlideLayout);
-
-        XSLFSlideMaster srcSlideMaster = srcSlide.getSlideMaster();
-        XSLFSlideMaster newSlideMaster = newSlide.getSlideMaster();
-        newSlideMaster.importContent(srcSlideMaster);
-
-        newSlide.importContent(srcSlide);
-        XMLSlideShow rwPptx = XSLFTestDataSamples.writeOutAndReadBack(newPptx);
-
-        PaintStyle ps = rwPptx.getSlides().get(0).getBackground().getFillStyle().getPaint();
-        assertTrue(ps instanceof TexturePaint);
-
-        rwPptx.close();
-        newPptx.close();
-        srcPptx.close();
+        try (XMLSlideShow srcPptx = openSampleDocument("pptx2svg.pptx");
+             XMLSlideShow newPptx = new XMLSlideShow()) {
+            XSLFSlide srcSlide = srcPptx.getSlides().get(0);
+            XSLFSlide newSlide = newPptx.createSlide();
+
+            XSLFSlideLayout srcSlideLayout = srcSlide.getSlideLayout();
+            XSLFSlideLayout newSlideLayout = newSlide.getSlideLayout();
+            newSlideLayout.importContent(srcSlideLayout);
+
+            XSLFSlideMaster srcSlideMaster = srcSlide.getSlideMaster();
+            XSLFSlideMaster newSlideMaster = newSlide.getSlideMaster();
+            newSlideMaster.importContent(srcSlideMaster);
+
+            newSlide.importContent(srcSlide);
+            try (XMLSlideShow rwPptx = writeOutAndReadBack(newPptx)) {
+                PaintStyle ps = rwPptx.getSlides().get(0).getBackground().getFillStyle().getPaint();
+                assertTrue(ps instanceof TexturePaint);
+            }
+        }
     }
 
     @Test
     void bug59273() throws IOException {
-        XMLSlideShow ppt = openSampleDocument("bug59273.potx");
-        ppt.getPackage().replaceContentType(
-            XSLFRelation.PRESENTATIONML_TEMPLATE.getContentType(),
-            XSLFRelation.MAIN.getContentType()
-        );
-
-        XMLSlideShow rwPptx = XSLFTestDataSamples.writeOutAndReadBack(ppt);
-        OPCPackage pkg = rwPptx.getPackage();
-        int size = pkg.getPartsByContentType(XSLFRelation.MAIN.getContentType()).size();
-        assertEquals(1, size);
-        size = pkg.getPartsByContentType(XSLFRelation.PRESENTATIONML_TEMPLATE.getContentType()).size();
-        assertEquals(0, size);
-
-        rwPptx.close();
-        ppt.close();
+        try (XMLSlideShow ppt = openSampleDocument("bug59273.potx")) {
+            ppt.getPackage().replaceContentType(
+                XSLFRelation.PRESENTATIONML_TEMPLATE.getContentType(),
+                XSLFRelation.MAIN.getContentType()
+            );
+
+            try (XMLSlideShow rwPptx = writeOutAndReadBack(ppt)) {
+                OPCPackage pkg = rwPptx.getPackage();
+                int size = pkg.getPartsByContentType(XSLFRelation.MAIN.getContentType()).size();
+                assertEquals(1, size);
+                size = pkg.getPartsByContentType(XSLFRelation.PRESENTATIONML_TEMPLATE.getContentType()).size();
+                assertEquals(0, size);
+            }
+        }
     }
 
 
     @Test
     void bug60373() throws IOException {
-        XMLSlideShow ppt = new XMLSlideShow();
-        XSLFSlide sl = ppt.createSlide();
-        XSLFTable t = sl.createTable();
-        XSLFTableRow r = t.addRow();
-        bug60373_addCell(r);
-        bug60373_addCell(r);
-        r = t.addRow();
-        XSLFTableCell c = bug60373_addCell(r);
-        // call getTextHeight, when table is not fully populated
-        double th = c.getTextHeight();
-        assertTrue(th > 10);
-        ppt.close();
+        try (XMLSlideShow ppt = new XMLSlideShow()) {
+            XSLFSlide sl = ppt.createSlide();
+            XSLFTable t = sl.createTable();
+            XSLFTableRow r = t.addRow();
+            bug60373_addCell(r);
+            bug60373_addCell(r);
+            r = t.addRow();
+            XSLFTableCell c = bug60373_addCell(r);
+            // call getTextHeight, when table is not fully populated
+            double th = c.getTextHeight();
+            assertTrue(th > 10);
+        }
     }
 
     private static XSLFTableCell bug60373_addCell(XSLFTableRow r) {
@@ -834,42 +805,39 @@ class TestXSLFBugs {
 
     @Test
     void bug60662() throws IOException {
-        XMLSlideShow src = new XMLSlideShow();
-        XSLFSlide sl = src.createSlide();
-        XSLFGroupShape gs = sl.createGroup();
-        gs.setAnchor(new Rectangle2D.Double(100, 100, 100, 100));
-        gs.setInteriorAnchor(new Rectangle2D.Double(0, 0, 100, 100));
-        XSLFAutoShape as = gs.createAutoShape();
-        as.setAnchor(new Rectangle2D.Double(0, 0, 100, 100));
-        as.setShapeType(ShapeType.STAR_24);
-        as.setFillColor(Color.YELLOW);
-        CTShape csh = (CTShape) as.getXmlObject();
-        CTOuterShadowEffect shadow = csh.getSpPr().addNewEffectLst().addNewOuterShdw();
-        shadow.setDir(270000);
-        shadow.setDist(100000);
-        shadow.addNewSrgbClr().setVal(new byte[]{0x00, (byte) 0xFF, 0x00});
-
-        XMLSlideShow dst = new XMLSlideShow();
-        XSLFSlide sl2 = dst.createSlide();
-        sl2.importContent(sl);
-        XSLFGroupShape gs2 = (XSLFGroupShape) sl2.getShapes().get(0);
-        XSLFAutoShape as2 = (XSLFAutoShape) gs2.getShapes().get(0);
-        CTShape csh2 = (CTShape) as2.getXmlObject();
-        assertTrue(csh2.getSpPr().isSetEffectLst());
-
-        dst.close();
-        src.close();
+        try (XMLSlideShow src = new XMLSlideShow();
+             XMLSlideShow dst = new XMLSlideShow()) {
+            XSLFSlide sl = src.createSlide();
+            XSLFGroupShape gs = sl.createGroup();
+            gs.setAnchor(new Rectangle2D.Double(100, 100, 100, 100));
+            gs.setInteriorAnchor(new Rectangle2D.Double(0, 0, 100, 100));
+            XSLFAutoShape as = gs.createAutoShape();
+            as.setAnchor(new Rectangle2D.Double(0, 0, 100, 100));
+            as.setShapeType(ShapeType.STAR_24);
+            as.setFillColor(Color.YELLOW);
+            CTShape csh = (CTShape) as.getXmlObject();
+            CTOuterShadowEffect shadow = csh.getSpPr().addNewEffectLst().addNewOuterShdw();
+            shadow.setDir(270000);
+            shadow.setDist(100000);
+            shadow.addNewSrgbClr().setVal(new byte[]{0x00, (byte) 0xFF, 0x00});
+
+            XSLFSlide sl2 = dst.createSlide();
+            sl2.importContent(sl);
+            XSLFGroupShape gs2 = (XSLFGroupShape) sl2.getShapes().get(0);
+            XSLFAutoShape as2 = (XSLFAutoShape) gs2.getShapes().get(0);
+            CTShape csh2 = (CTShape) as2.getXmlObject();
+            assertTrue(csh2.getSpPr().isSetEffectLst());
+        }
     }
 
     @Test
     void test60810() throws IOException {
-        XMLSlideShow ppt = openSampleDocument("60810.pptx");
-        for (XSLFSlide slide : ppt.getSlides()) {
-            XSLFNotes notesSlide = ppt.getNotesSlide(slide);
-            assertNotNull(notesSlide);
+        try (XMLSlideShow ppt = openSampleDocument("60810.pptx")) {
+            for (XSLFSlide slide : ppt.getSlides()) {
+                XSLFNotes notesSlide = ppt.getNotesSlide(slide);
+                assertNotNull(notesSlide);
+            }
         }
-
-        ppt.close();
     }
 
     @Test
@@ -886,7 +854,7 @@ class TestXSLFBugs {
         try (XMLSlideShow ppt = openSampleDocument("61515.pptx")) {
             ppt.removeSlide(0);
             assertEquals(1, ppt.createSlide().getRelations().size());
-            try (XMLSlideShow saved = XSLFTestDataSamples.writeOutAndReadBack(ppt)) {
+            try (XMLSlideShow saved = writeOutAndReadBack(ppt)) {
                 assertEquals(1, saved.getSlides().size());
                 XSLFSlide slide = saved.getSlides().get(0);
                 assertEquals(1, slide.getRelations().size());
@@ -897,7 +865,7 @@ class TestXSLFBugs {
     @Test
     void testAptia() throws IOException {
         try (XMLSlideShow ppt = openSampleDocument("aptia.pptx");
-             XMLSlideShow saved = XSLFTestDataSamples.writeOutAndReadBack(ppt)) {
+             XMLSlideShow saved = writeOutAndReadBack(ppt)) {
             assertEquals(ppt.getSlides().size(), saved.getSlides().size());
         }
     }
@@ -906,7 +874,7 @@ class TestXSLFBugs {
     @Test
     void testDivinoRevelado() throws IOException {
         try (XMLSlideShow ppt = openSampleDocument("Divino_Revelado.pptx");
-             XMLSlideShow saved = XSLFTestDataSamples.writeOutAndReadBack(ppt)) {
+             XMLSlideShow saved = writeOutAndReadBack(ppt)) {
             assertEquals(ppt.getSlides().size(), saved.getSlides().size());
         }
     }
diff --git a/poi-ooxml/src/test/java/org/apache/poi/xslf/XSLFTestDataSamples.java b/poi-ooxml/src/test/java/org/apache/poi/xslf/XSLFTestDataSamples.java
index d902c12714..897fcd1d27 100644
--- a/poi-ooxml/src/test/java/org/apache/poi/xslf/XSLFTestDataSamples.java
+++ b/poi-ooxml/src/test/java/org/apache/poi/xslf/XSLFTestDataSamples.java
@@ -16,54 +16,32 @@
 ==================================================================== */
 package org.apache.poi.xslf;
 
+import java.io.IOException;
+import java.io.InputStream;
+
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.POIDataSamples;
 import org.apache.poi.openxml4j.opc.OPCPackage;
 import org.apache.poi.xslf.usermodel.XMLSlideShow;
 
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
-import java.io.IOException;
-import java.io.InputStream;
-
 public class XSLFTestDataSamples {
 
     public static XMLSlideShow openSampleDocument(String sampleName) {
-        InputStream is = POIDataSamples.getSlideShowInstance().openResourceAsStream(sampleName);
-        try {
+        try (InputStream is = POIDataSamples.getSlideShowInstance().openResourceAsStream(sampleName)) {
             return new XMLSlideShow(OPCPackage.open(is));
         } catch (Exception e) {
             throw new RuntimeException(e);
-        } finally {
-            try {
-                is.close();
-            } catch (IOException e) {
-                throw new RuntimeException(e);
-            }
         }
     }
 
     public static XMLSlideShow writeOutAndReadBack(XMLSlideShow doc) throws IOException {
-        ByteArrayOutputStream baos = new ByteArrayOutputStream(4096);
-        try {
+        try (UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream(4096)) {
             doc.write(baos);
+            try (InputStream bais = baos.toInputStream()) {
+                return new XMLSlideShow(bais);
+            }
         } catch (IOException e) {
             throw new RuntimeException(e);
         }
-
-        InputStream bais;
-        bais = new ByteArrayInputStream(baos.toByteArray());
-        try {
-            return new XMLSlideShow(OPCPackage.open(bais));
-        } catch (Exception e) {
-            throw new RuntimeException(e);
-        } finally {
-            try {
-                baos.close();
-                bais.close();
-            } catch (IOException e) {
-                throw new RuntimeException(e);
-            }
-        }
-
     }
 }
diff --git a/poi-ooxml/src/test/java/org/apache/poi/xslf/usermodel/TestXMLSlideShow.java b/poi-ooxml/src/test/java/org/apache/poi/xslf/usermodel/TestXMLSlideShow.java
index 520f62fb04..295767a75c 100644
--- a/poi-ooxml/src/test/java/org/apache/poi/xslf/usermodel/TestXMLSlideShow.java
+++ b/poi-ooxml/src/test/java/org/apache/poi/xslf/usermodel/TestXMLSlideShow.java
@@ -16,14 +16,14 @@
 ==================================================================== */
 package org.apache.poi.xslf.usermodel;
 
+import static org.apache.poi.xslf.XSLFTestDataSamples.openSampleDocument;
+import static org.apache.poi.xslf.XSLFTestDataSamples.writeOutAndReadBack;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertNull;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 
 import org.apache.poi.openxml4j.opc.OPCPackage;
@@ -69,133 +69,119 @@ class TestXMLSlideShow extends BaseTestSlideShow<XSLFShape, XSLFTextParagraph> {
     @Test
     void testOpen() throws Exception {
         // With the finalised uri, should be fine
-        XMLSlideShow xml = new XMLSlideShow(pack);
-        // Check the core
-        assertNotNull(xml.getCTPresentation());
+        try (XMLSlideShow xml = new XMLSlideShow(pack)) {
+            // Check the core
+            assertNotNull(xml.getCTPresentation());
 
-        // Check it has some slides
-        assertFalse(xml.getSlides().isEmpty());
-        assertFalse(xml.getSlideMasters().isEmpty());
-
-        xml.close();
+            // Check it has some slides
+            assertFalse(xml.getSlides().isEmpty());
+            assertFalse(xml.getSlideMasters().isEmpty());
+        }
     }
 
-    @SuppressWarnings("deprecation")
     @Test
     void testSlideBasics() throws IOException {
-        XMLSlideShow xml = new XMLSlideShow(pack);
+        try (XMLSlideShow xml = new XMLSlideShow(pack)) {
 
-        // Should have 1 master
-        assertEquals(1, xml.getSlideMasters().size());
+            // Should have 1 master
+            assertEquals(1, xml.getSlideMasters().size());
 
-        // Should have two sheets
-        assertEquals(2, xml.getSlides().size());
+            // Should have two sheets
+            assertEquals(2, xml.getSlides().size());
 
-        // Check they're as expected
-        CTSlideIdListEntry[] slides = xml.getCTPresentation().getSldIdLst().getSldIdArray();
+            // Check they're as expected
+            CTSlideIdListEntry[] slides = xml.getCTPresentation().getSldIdLst().getSldIdArray();
 
-        assertEquals(256, slides[0].getId());
-        assertEquals(257, slides[1].getId());
-        assertEquals("rId2", slides[0].getId2());
-        assertEquals("rId3", slides[1].getId2());
+            assertEquals(256, slides[0].getId());
+            assertEquals(257, slides[1].getId());
+            assertEquals("rId2", slides[0].getId2());
+            assertEquals("rId3", slides[1].getId2());
 
-        // Now get those objects
-        assertNotNull(xml.getSlides().get(0));
-        assertNotNull(xml.getSlides().get(1));
+            // Now get those objects
+            assertNotNull(xml.getSlides().get(0));
+            assertNotNull(xml.getSlides().get(1));
 
-        // And check they have notes as expected
-        assertNotNull(xml.getSlides().get(0).getNotes());
-        assertNotNull(xml.getSlides().get(1).getNotes());
+            // And check they have notes as expected
+            assertNotNull(xml.getSlides().get(0).getNotes());
+            assertNotNull(xml.getSlides().get(1).getNotes());
 
-        // Next up look for the slide master
-        CTSlideMasterIdListEntry[] masters = xml.getCTPresentation().getSldMasterIdLst().getSldMasterIdArray();
+            // Next up look for the slide master
+            CTSlideMasterIdListEntry[] masters = xml.getCTPresentation().getSldMasterIdLst().getSldMasterIdArray();
 
-        // see SlideAtom.USES_MASTER_SLIDE_ID
-        assertEquals(0x80000000L, masters[0].getId());
-        assertEquals("rId1", masters[0].getId2());
-        assertNotNull(xml.getSlideMasters().get(0));
+            // see SlideAtom.USES_MASTER_SLIDE_ID
+            assertEquals(0x80000000L, masters[0].getId());
+            assertEquals("rId1", masters[0].getId2());
+            assertNotNull(xml.getSlideMasters().get(0));
 
-        // Finally look for the notes master
-        CTNotesMasterIdListEntry notesMaster =
-            xml.getCTPresentation().getNotesMasterIdLst().getNotesMasterId();
-        assertNotNull(notesMaster);
+            // Finally look for the notes master
+            CTNotesMasterIdListEntry notesMaster =
+                xml.getCTPresentation().getNotesMasterIdLst().getNotesMasterId();
+            assertNotNull(notesMaster);
 
-        assertNotNull(xml.getNotesMaster());
-
-        xml.close();
+            assertNotNull(xml.getNotesMaster());
+        }
     }
 
     @Test
     void testMetadataBasics() throws IOException {
-        XMLSlideShow xml = new XMLSlideShow(pack);
+        try (XMLSlideShow xml = new XMLSlideShow(pack)) {
 
-        assertNotNull(xml.getProperties().getCoreProperties());
-        assertNotNull(xml.getProperties().getExtendedProperties());
+            assertNotNull(xml.getProperties().getCoreProperties());
+            assertNotNull(xml.getProperties().getExtendedProperties());
 
-        assertEquals("Microsoft Office PowerPoint", xml.getProperties().getExtendedProperties().getUnderlyingProperties().getApplication());
-        assertEquals(0, xml.getProperties().getExtendedProperties().getUnderlyingProperties().getCharacters());
-        assertEquals(0, xml.getProperties().getExtendedProperties().getUnderlyingProperties().getLines());
+            assertEquals("Microsoft Office PowerPoint", xml.getProperties().getExtendedProperties().getUnderlyingProperties().getApplication());
+            assertEquals(0, xml.getProperties().getExtendedProperties().getUnderlyingProperties().getCharacters());
+            assertEquals(0, xml.getProperties().getExtendedProperties().getUnderlyingProperties().getLines());
 
-        assertNull(xml.getProperties().getCoreProperties().getTitle());
-        assertFalse(xml.getProperties().getCoreProperties().getUnderlyingProperties().getSubjectProperty().isPresent());
-
-        xml.close();
+            assertNull(xml.getProperties().getCoreProperties().getTitle());
+            assertFalse(xml.getProperties().getCoreProperties().getUnderlyingProperties().getSubjectProperty().isPresent());
+        }
     }
 
     @Test
     void testComments() throws Exception {
         // Default sample file has none
-        XMLSlideShow xml = new XMLSlideShow(pack);
-
-        assertNull(xml.getCommentAuthors());
+        try (XMLSlideShow xml = new XMLSlideShow(pack)) {
+            assertNull(xml.getCommentAuthors());
 
-        for (XSLFSlide slide : xml.getSlides()) {
-            assertTrue(slide.getComments().isEmpty());
+            for (XSLFSlide slide : xml.getSlides()) {
+                assertTrue(slide.getComments().isEmpty());
+            }
         }
 
         // Try another with comments
-        XMLSlideShow xmlComments = new XMLSlideShow(slTests.openResourceAsStream("45545_Comment.pptx"));
-
-        // Has one author
-        assertNotNull(xmlComments.getCommentAuthors());
-        assertEquals(1, xmlComments.getCommentAuthors().getCTCommentAuthorsList().sizeOfCmAuthorArray());
-        assertEquals("XPVMWARE01", xmlComments.getCommentAuthors().getAuthorById(0).getName());
-
-        // First two slides have comments
-        int i = -1;
-        for (XSLFSlide slide : xmlComments.getSlides()) {
-            i++;
-
-            if (i == 0) {
-                assertNotNull(slide.getCommentsPart());
-                assertEquals(1, slide.getCommentsPart().getNumberOfComments());
-                assertEquals("testdoc", slide.getCommentsPart().getCommentAt(0).getText());
-                assertEquals(0, slide.getCommentsPart().getCommentAt(0).getAuthorId());
-            } else if (i == 1) {
-                assertNotNull(slide.getComments());
-                assertEquals(1, slide.getCommentsPart().getNumberOfComments());
-                assertEquals("test phrase", slide.getCommentsPart().getCommentAt(0).getText());
-                assertEquals(0, slide.getCommentsPart().getCommentAt(0).getAuthorId());
-            } else {
-                assertNull(slide.getCommentsPart());
-                assertTrue(slide.getComments().isEmpty());
+        try (XMLSlideShow xmlComments = openSampleDocument("45545_Comment.pptx")) {
+
+            // Has one author
+            assertNotNull(xmlComments.getCommentAuthors());
+            assertEquals(1, xmlComments.getCommentAuthors().getCTCommentAuthorsList().sizeOfCmAuthorArray());
+            assertEquals("XPVMWARE01", xmlComments.getCommentAuthors().getAuthorById(0).getName());
+
+            // First two slides have comments
+            int i = -1;
+            for (XSLFSlide slide : xmlComments.getSlides()) {
+                i++;
+
+                if (i == 0) {
+                    assertNotNull(slide.getCommentsPart());
+                    assertEquals(1, slide.getCommentsPart().getNumberOfComments());
+                    assertEquals("testdoc", slide.getCommentsPart().getCommentAt(0).getText());
+                    assertEquals(0, slide.getCommentsPart().getCommentAt(0).getAuthorId());
+                } else if (i == 1) {
+                    assertNotNull(slide.getComments());
+                    assertEquals(1, slide.getCommentsPart().getNumberOfComments());
+                    assertEquals("test phrase", slide.getCommentsPart().getCommentAt(0).getText());
+                    assertEquals(0, slide.getCommentsPart().getCommentAt(0).getAuthorId());
+                } else {
+                    assertNull(slide.getCommentsPart());
+                    assertTrue(slide.getComments().isEmpty());
+                }
             }
         }
-
-        xmlComments.close();
-        xml.close();
     }
 
     @Override
     public XMLSlideShow reopen(SlideShow<XSLFShape, XSLFTextParagraph> show) throws IOException {
-        BufAccessBAOS bos = new BufAccessBAOS();
-        show.write(bos);
-        return new XMLSlideShow(new ByteArrayInputStream(bos.getBuf()));
-    }
-
-    private static class BufAccessBAOS extends ByteArrayOutputStream {
-        byte[] getBuf() {
-            return buf;
-        }
+        return writeOutAndReadBack((XMLSlideShow) show);
     }
 }
diff --git a/poi-ooxml/src/test/java/org/apache/poi/xslf/usermodel/TestXSLFExamples.java b/poi-ooxml/src/test/java/org/apache/poi/xslf/usermodel/TestXSLFExamples.java
index 02640c0efe..78ae286f7e 100644
--- a/poi-ooxml/src/test/java/org/apache/poi/xslf/usermodel/TestXSLFExamples.java
+++ b/poi-ooxml/src/test/java/org/apache/poi/xslf/usermodel/TestXSLFExamples.java
@@ -21,12 +21,10 @@ import static org.apache.poi.openxml4j.opc.PackageRelationshipTypes.CORE_PROPERT
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.awt.Rectangle;
-import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.IOException;
 import java.net.URI;
 import java.net.URISyntaxException;
-import java.util.List;
 
 import javax.xml.namespace.QName;
 
diff --git a/poi-ooxml/src/test/java/org/apache/poi/xslf/usermodel/TestXSLFPictureShape.java b/poi-ooxml/src/test/java/org/apache/poi/xslf/usermodel/TestXSLFPictureShape.java
index 0df21b2720..37fb3318be 100644
--- a/poi-ooxml/src/test/java/org/apache/poi/xslf/usermodel/TestXSLFPictureShape.java
+++ b/poi-ooxml/src/test/java/org/apache/poi/xslf/usermodel/TestXSLFPictureShape.java
@@ -16,6 +16,8 @@
 ==================================================================== */
 package org.apache.poi.xslf.usermodel;
 
+import static org.apache.poi.xslf.XSLFTestDataSamples.openSampleDocument;
+import static org.apache.poi.xslf.XSLFTestDataSamples.writeOutAndReadBack;
 import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
@@ -25,8 +27,6 @@ import static org.junit.jupiter.api.Assertions.assertTrue;
 import static org.junit.jupiter.api.Assumptions.assumeFalse;
 
 import java.awt.geom.Rectangle2D;
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.FileOutputStream;
 import java.io.IOException;
@@ -41,7 +41,6 @@ import org.apache.poi.POIDataSamples;
 import org.apache.poi.sl.usermodel.PictureData.PictureType;
 import org.apache.poi.util.IOUtils;
 import org.apache.poi.util.TempFile;
-import org.apache.poi.xslf.XSLFTestDataSamples;
 import org.apache.poi.xslf.util.PPTX2PNG;
 import org.junit.jupiter.api.Test;
 import org.openxmlformats.schemas.presentationml.x2006.main.CTPicture;
@@ -51,245 +50,240 @@ class TestXSLFPictureShape {
 
     @Test
     void testCreate() throws Exception {
-        XMLSlideShow ppt1 = new XMLSlideShow();
-        assertEquals(0, ppt1.getPictureData().size());
-        byte[] data1 = new byte[100];
-        for(int i = 0;i < 100;i++) { data1[i] = (byte)i; }
-        XSLFPictureData pdata1 = ppt1.addPicture(data1, PictureType.JPEG);
-        assertEquals(0, pdata1.getIndex());
-        assertEquals(1, ppt1.getPictureData().size());
-
-        XSLFSlide slide = ppt1.createSlide();
-        XSLFPictureShape shape1 = slide.createPicture(pdata1);
-        assertNotNull(shape1.getPictureData());
-        assertArrayEquals(data1, shape1.getPictureData().getData());
-
-        byte[] data2 = new byte[200];
-        for(int i = 0;i < 200;i++) { data2[i] = (byte)i; }
-        XSLFPictureData pdata2 = ppt1.addPicture(data2, PictureType.PNG);
-        XSLFPictureShape shape2 = slide.createPicture(pdata2);
-        assertNotNull(shape2.getPictureData());
-        assertEquals(1, pdata2.getIndex());
-        assertEquals(2, ppt1.getPictureData().size());
-        assertArrayEquals(data2, shape2.getPictureData().getData());
-
-        XMLSlideShow ppt2 = XSLFTestDataSamples.writeOutAndReadBack(ppt1);
-        ppt1.close();
-        List<XSLFPictureData> pics = ppt2.getPictureData();
-        assertEquals(2, pics.size());
-        assertArrayEquals(data1, pics.get(0).getData());
-        assertArrayEquals(data2, pics.get(1).getData());
-
-        List<XSLFShape> shapes = ppt2.getSlides().get(0).getShapes();
-        assertArrayEquals(data1, ((XSLFPictureShape) shapes.get(0)).getPictureData().getData());
-        assertArrayEquals(data2, ((XSLFPictureShape) shapes.get(1)).getPictureData().getData());
-        ppt2.close();
+        try (XMLSlideShow ppt1 = new XMLSlideShow()) {
+            assertEquals(0, ppt1.getPictureData().size());
+            byte[] data1 = new byte[100];
+            for (int i = 0; i < 100; i++) {
+                data1[i] = (byte) i;
+            }
+            XSLFPictureData pdata1 = ppt1.addPicture(data1, PictureType.JPEG);
+            assertEquals(0, pdata1.getIndex());
+            assertEquals(1, ppt1.getPictureData().size());
+
+            XSLFSlide slide = ppt1.createSlide();
+            XSLFPictureShape shape1 = slide.createPicture(pdata1);
+            assertNotNull(shape1.getPictureData());
+            assertArrayEquals(data1, shape1.getPictureData().getData());
+
+            byte[] data2 = new byte[200];
+            for (int i = 0; i < 200; i++) {
+                data2[i] = (byte) i;
+            }
+            XSLFPictureData pdata2 = ppt1.addPicture(data2, PictureType.PNG);
+            XSLFPictureShape shape2 = slide.createPicture(pdata2);
+            assertNotNull(shape2.getPictureData());
+            assertEquals(1, pdata2.getIndex());
+            assertEquals(2, ppt1.getPictureData().size());
+            assertArrayEquals(data2, shape2.getPictureData().getData());
+
+            try (XMLSlideShow ppt2 = writeOutAndReadBack(ppt1)) {
+                List<XSLFPictureData> pics = ppt2.getPictureData();
+                assertEquals(2, pics.size());
+                assertArrayEquals(data1, pics.get(0).getData());
+                assertArrayEquals(data2, pics.get(1).getData());
+
+                List<XSLFShape> shapes = ppt2.getSlides().get(0).getShapes();
+                assertArrayEquals(data1, ((XSLFPictureShape) shapes.get(0)).getPictureData().getData());
+                assertArrayEquals(data2, ((XSLFPictureShape) shapes.get(1)).getPictureData().getData());
+            }
+        }
     }
 
     @Test
     void testCreateMultiplePictures() throws Exception {
-        XMLSlideShow ppt1 = new XMLSlideShow();
-        XSLFSlide slide1 = ppt1.createSlide();
-        XSLFGroupShape group1 = slide1.createGroup();
-
-
-        int pictureIndex = 0;
-        // first add 20 images to the slide
-        for (int i = 0; i < 20; i++, pictureIndex++) {
-            byte[] data = new byte[]{(byte)pictureIndex};
-            XSLFPictureData elementData = ppt1.addPicture(data, PictureType.PNG);
-            assertEquals(pictureIndex, elementData.getIndex());   // added images have indexes 0,1,2....19
-            XSLFPictureShape picture = slide1.createPicture(elementData);
-            // POI saves images as image1.png, image2.png, etc.
-            String fileName = "image" + (elementData.getIndex()+1) + ".png";
-            assertEquals(fileName, picture.getPictureData().getFileName());
-            assertArrayEquals(data, picture.getPictureData().getData());
-        }
-
-        // and then add next 20 images to a group
-        for (int i = 0; i < 20; i++, pictureIndex++) {
-            byte[] data = new byte[]{(byte)pictureIndex};
-            XSLFPictureData elementData = ppt1.addPicture(data, PictureType.PNG);
-            XSLFPictureShape picture = group1.createPicture(elementData);
-            // POI saves images as image1.png, image2.png, etc.
-            assertEquals(pictureIndex, elementData.getIndex());   // added images have indexes 0,1,2....19
-            String fileName = "image" + (pictureIndex + 1) + ".png";
-            assertEquals(fileName, picture.getPictureData().getFileName());
-            assertArrayEquals(data, picture.getPictureData().getData());
-        }
+        try (XMLSlideShow ppt1 = new XMLSlideShow()) {
+            XSLFSlide slide1 = ppt1.createSlide();
+            XSLFGroupShape group1 = slide1.createGroup();
+
+
+            int pictureIndex = 0;
+            // first add 20 images to the slide
+            for (int i = 0; i < 20; i++, pictureIndex++) {
+                byte[] data = new byte[]{(byte) pictureIndex};
+                XSLFPictureData elementData = ppt1.addPicture(data, PictureType.PNG);
+                assertEquals(pictureIndex, elementData.getIndex());   // added images have indexes 0,1,2....19
+                XSLFPictureShape picture = slide1.createPicture(elementData);
+                // POI saves images as image1.png, image2.png, etc.
+                String fileName = "image" + (elementData.getIndex() + 1) + ".png";
+                assertEquals(fileName, picture.getPictureData().getFileName());
+                assertArrayEquals(data, picture.getPictureData().getData());
+            }
 
-        // serialize, read back and check that all images are there
+            // and then add next 20 images to a group
+            for (int i = 0; i < 20; i++, pictureIndex++) {
+                byte[] data = new byte[]{(byte) pictureIndex};
+                XSLFPictureData elementData = ppt1.addPicture(data, PictureType.PNG);
+                XSLFPictureShape picture = group1.createPicture(elementData);
+                // POI saves images as image1.png, image2.png, etc.
+                assertEquals(pictureIndex, elementData.getIndex());   // added images have indexes 0,1,2....19
+                String fileName = "image" + (pictureIndex + 1) + ".png";
+                assertEquals(fileName, picture.getPictureData().getFileName());
+                assertArrayEquals(data, picture.getPictureData().getData());
+            }
 
-        XMLSlideShow ppt2 = XSLFTestDataSamples.writeOutAndReadBack(ppt1);
-        ppt1.close();
-        // pictures keyed by file name
-        Map<String, XSLFPictureData> pics = new HashMap<>();
-        for(XSLFPictureData p : ppt2.getPictureData()){
-            pics.put(p.getFileName(), p);
-        }
-        assertEquals(40, pics.size());
-        for (int i = 0; i < 40; i++) {
-            byte[] data1 = new byte[]{(byte)i};
-            String fileName = "image" + (i + 1) + ".png";
-            XSLFPictureData data = pics.get(fileName);
-            assertNotNull(data);
-            assertEquals(fileName, data.getFileName());
-            assertArrayEquals(data1, data.getData());
+            // serialize, read back and check that all images are there
+
+            try (XMLSlideShow ppt2 = writeOutAndReadBack(ppt1)) {
+                // pictures keyed by file name
+                Map<String, XSLFPictureData> pics = new HashMap<>();
+                for (XSLFPictureData p : ppt2.getPictureData()) {
+                    pics.put(p.getFileName(), p);
+                }
+                assertEquals(40, pics.size());
+                for (int i = 0; i < 40; i++) {
+                    byte[] data1 = new byte[]{(byte) i};
+                    String fileName = "image" + (i + 1) + ".png";
+                    XSLFPictureData data = pics.get(fileName);
+                    assertNotNull(data);
+                    assertEquals(fileName, data.getFileName());
+                    assertArrayEquals(data1, data.getData());
+                }
+            }
         }
-        ppt2.close();
     }
 
     @Test
     void testImageCaching() throws Exception {
-        XMLSlideShow ppt = new XMLSlideShow();
-        byte[] img1 = new byte[]{1,2,3};
-        byte[] img2 = new byte[]{3,4,5};
-        XSLFPictureData pdata1 = ppt.addPicture(img1, PictureType.PNG);
-        assertEquals(0, pdata1.getIndex());
-        assertEquals(0, ppt.addPicture(img1, PictureType.PNG).getIndex());
-
-        XSLFPictureData idx2 = ppt.addPicture(img2, PictureType.PNG);
-        assertEquals(1, idx2.getIndex());
-        assertEquals(1, ppt.addPicture(img2, PictureType.PNG).getIndex());
-
-        XSLFSlide slide1 = ppt.createSlide();
-        assertNotNull(slide1);
-        XSLFSlide slide2 = ppt.createSlide();
-        assertNotNull(slide2);
-
-        ppt.close();
+        try (XMLSlideShow ppt = new XMLSlideShow()) {
+            byte[] img1 = new byte[]{1, 2, 3};
+            byte[] img2 = new byte[]{3, 4, 5};
+            XSLFPictureData pdata1 = ppt.addPicture(img1, PictureType.PNG);
+            assertEquals(0, pdata1.getIndex());
+            assertEquals(0, ppt.addPicture(img1, PictureType.PNG).getIndex());
+
+            XSLFPictureData idx2 = ppt.addPicture(img2, PictureType.PNG);
+            assertEquals(1, idx2.getIndex());
+            assertEquals(1, ppt.addPicture(img2, PictureType.PNG).getIndex());
+
+            XSLFSlide slide1 = ppt.createSlide();
+            assertNotNull(slide1);
+            XSLFSlide slide2 = ppt.createSlide();
+            assertNotNull(slide2);
+        }
     }
 
     @Test
     void testMerge() throws Exception {
-        XMLSlideShow ppt1 = new XMLSlideShow();
-        byte[] data1 = new byte[100];
-        XSLFPictureData pdata1 = ppt1.addPicture(data1, PictureType.JPEG);
+        try (XMLSlideShow ppt1 = new XMLSlideShow()) {
+            byte[] data1 = new byte[100];
+            XSLFPictureData pdata1 = ppt1.addPicture(data1, PictureType.JPEG);
 
-        XSLFSlide slide1 = ppt1.createSlide();
-        XSLFPictureShape shape1 = slide1.createPicture(pdata1);
-        CTPicture ctPic1 = (CTPicture)shape1.getXmlObject();
-        ctPic1.getNvPicPr().getNvPr().addNewCustDataLst().addNewTags().setId("rId99");
+            XSLFSlide slide1 = ppt1.createSlide();
+            XSLFPictureShape shape1 = slide1.createPicture(pdata1);
+            CTPicture ctPic1 = (CTPicture) shape1.getXmlObject();
+            ctPic1.getNvPicPr().getNvPr().addNewCustDataLst().addNewTags().setId("rId99");
 
-        XSLFPictureShape shape2 = slide1.createPicture(pdata1);
-        CTPicture ctPic2 = (CTPicture)shape2.getXmlObject();
-        ctPic2.getNvPicPr().getNvPr().addNewCustDataLst().addNewTags().setId("rId99");
+            XSLFPictureShape shape2 = slide1.createPicture(pdata1);
+            CTPicture ctPic2 = (CTPicture) shape2.getXmlObject();
+            ctPic2.getNvPicPr().getNvPr().addNewCustDataLst().addNewTags().setId("rId99");
 
-        differentShapeName(shape1, shape2);
+            differentShapeName(shape1, shape2);
 
-        XSLFGroupShape group = slide1.createGroup();
-        XSLFTextBox tb1 = group.createTextBox();
-        XSLFTextBox tb2 = group.createTextBox();
+            XSLFGroupShape group = slide1.createGroup();
+            XSLFTextBox tb1 = group.createTextBox();
+            XSLFTextBox tb2 = group.createTextBox();
 
-        assertNotEquals("We should have different names now, but had: " + tb1.getShapeName() + " for both", tb1.getShapeName(), tb2.getShapeName());
+            differentShapeName(tb1, tb2);
 
-        XMLSlideShow pptCopy = new XMLSlideShow();
+            try (XMLSlideShow pptCopy = new XMLSlideShow()) {
+                XSLFSlide slideCopy = pptCopy.createSlide().importContent(slide1);
+                XSLFPictureShape shapeCopy1 = (XSLFPictureShape) slideCopy.getShapes().get(0);
 
-        XSLFSlide slideCopy = pptCopy.createSlide().importContent(slide1);
-        XSLFPictureShape shapeCopy1 = (XSLFPictureShape)slideCopy.getShapes().get(0);
+                assertArrayEquals(data1, shapeCopy1.getPictureData().getData());
+                assertEquals(shape1.getShapeName(), shapeCopy1.getShapeName());
 
-        assertArrayEquals(data1, shapeCopy1.getPictureData().getData());
-        assertEquals(shape1.getShapeName(), shapeCopy1.getShapeName());
+                CTPicture ctPicCopy1 = (CTPicture) shapeCopy1.getXmlObject();
+                assertFalse(ctPicCopy1.getNvPicPr().getNvPr().isSetCustDataLst());
 
-        CTPicture ctPicCopy1 = (CTPicture)shapeCopy1.getXmlObject();
-        assertFalse(ctPicCopy1.getNvPicPr().getNvPr().isSetCustDataLst());
+                XSLFPictureShape shapeCopy2 = (XSLFPictureShape) slideCopy.getShapes().get(1);
 
-        XSLFPictureShape shapeCopy2 = (XSLFPictureShape)slideCopy.getShapes().get(1);
+                assertArrayEquals(data1, shapeCopy2.getPictureData().getData());
+                assertEquals(shape2.getShapeName(), shapeCopy2.getShapeName());
 
-        assertArrayEquals(data1, shapeCopy2.getPictureData().getData());
-        assertEquals(shape2.getShapeName(), shapeCopy2.getShapeName());
+                CTPicture ctPicCopy2 = (CTPicture) shapeCopy2.getXmlObject();
+                assertFalse(ctPicCopy2.getNvPicPr().getNvPr().isSetCustDataLst());
 
-        CTPicture ctPicCopy2 = (CTPicture)shapeCopy2.getXmlObject();
-        assertFalse(ctPicCopy2.getNvPicPr().getNvPr().isSetCustDataLst());
+                differentShapeName(shapeCopy1, shapeCopy2);
 
-        differentShapeName(shapeCopy1, shapeCopy2);
+                XSLFGroupShape groupCopy = (XSLFGroupShape) slideCopy.getShapes().get(2);
+                XSLFTextBox tbCopy1 = (XSLFTextBox) groupCopy.getShapes().get(0);
+                XSLFTextBox tbCopy2 = (XSLFTextBox) groupCopy.getShapes().get(1);
 
-        XSLFGroupShape groupCopy = (XSLFGroupShape) slideCopy.getShapes().get(2);
-        XSLFTextBox tbCopy1 = (XSLFTextBox) groupCopy.getShapes().get(0);
-        XSLFTextBox tbCopy2 = (XSLFTextBox) groupCopy.getShapes().get(1);
+                assertEquals(group.getShapeName(), groupCopy.getShapeName());
+                assertEquals(tb1.getShapeName(), tbCopy1.getShapeName());
+                assertEquals(tb2.getShapeName(), tbCopy2.getShapeName());
 
-        assertEquals(group.getShapeName(), groupCopy.getShapeName());
-        assertEquals(tb1.getShapeName(), tbCopy1.getShapeName());
-        assertEquals(tb2.getShapeName(), tbCopy2.getShapeName());
-
-        differentShapeName(tb1, tb2);
-
-        ppt1.close();
-        pptCopy.close();
+                differentShapeName(tb1, tb2);
+            }
+        }
     }
 
     private void differentShapeName(XSLFShape shape1, XSLFShape shape2) {
-        assertNotEquals("We should have different names now, but had: " + shape1.getShapeName() + " for both", shape1.getShapeName(), shape2.getShapeName());
+        assertNotEquals(shape1.getShapeName(), shape2.getShapeName(),
+            "We should have different names now, but had: " + shape1.getShapeName() + " for both");
     }
 
     @Test
     void bug58663() throws IOException {
-        InputStream is = _slTests.openResourceAsStream("shapes.pptx");
-        XMLSlideShow ppt = new XMLSlideShow(is);
-        is.close();
-
-        XSLFSlide slide = ppt.getSlides().get(0);
-        XSLFPictureShape ps = (XSLFPictureShape)slide.getShapes().get(3);
-        slide.removeShape(ps);
-
-        ByteArrayOutputStream bos = new ByteArrayOutputStream();
-        ppt.write(bos);
-        ppt.close();
+        try (XMLSlideShow ppt = openSampleDocument("shapes.pptx")) {
+            XSLFSlide slide = ppt.getSlides().get(0);
+            XSLFPictureShape ps = (XSLFPictureShape) slide.getShapes().get(3);
+            slide.removeShape(ps);
 
-        XMLSlideShow ppt2 = new XMLSlideShow(new ByteArrayInputStream(bos.toByteArray()));
-        assertTrue(ppt2.getPictureData().isEmpty());
-        ppt2.close();
+            try (XMLSlideShow ppt2 = writeOutAndReadBack(ppt)) {
+                assertTrue(ppt2.getPictureData().isEmpty());
+            }
+        }
     }
 
     @Test
     void testTiffImageBug59742() throws Exception {
-        XMLSlideShow slideShow = new XMLSlideShow();
-        final InputStream tiffStream = _slTests.openResourceAsStream("testtiff.tif");
-        final byte[] pictureData = IOUtils.toByteArray(tiffStream);
-        IOUtils.closeQuietly(tiffStream);
-
-        XSLFPictureData pic = slideShow.addPicture(pictureData, PictureType.TIFF);
-        assertEquals("image/tiff", pic.getContentType());
-        assertEquals("image1.tiff", pic.getFileName());
+        try (XMLSlideShow slideShow = new XMLSlideShow();
+            InputStream tiffStream = _slTests.openResourceAsStream("testtiff.tif")) {
+            final byte[] pictureData = IOUtils.toByteArray(tiffStream);
 
-        slideShow.close();
+            XSLFPictureData pic = slideShow.addPicture(pictureData, PictureType.TIFF);
+            assertEquals("image/tiff", pic.getContentType());
+            assertEquals("image1.tiff", pic.getFileName());
+        }
     }
 
 
     @Test
     void renderSvgImage() throws Exception {
-        XMLSlideShow ppt = new XMLSlideShow();
-        XSLFSlide slide = ppt.createSlide();
+        try (XMLSlideShow ppt = new XMLSlideShow()) {
+            XSLFSlide slide = ppt.createSlide();
 
-        try {
-            XSLFPictureData svgPic = ppt.addPicture(POIDataSamples.getDocumentInstance().getFile("../project-header.svg"), PictureType.SVG);
-            XSLFPictureShape shape = XSLFPictureShape.addSvgImage(slide, svgPic, PictureType.JPEG, null);
+            try {
+                XSLFPictureData svgPic = ppt.addPicture(POIDataSamples.getDocumentInstance().getFile("../project-header.svg"), PictureType.SVG);
+                XSLFPictureShape shape = XSLFPictureShape.addSvgImage(slide, svgPic, PictureType.JPEG, null);
 
-            Rectangle2D anchor = shape.getAnchor();
-            anchor.setRect(100, 100, anchor.getWidth(), anchor.getHeight());
-            shape.setAnchor(anchor);
+                Rectangle2D anchor = shape.getAnchor();
+                anchor.setRect(100, 100, anchor.getWidth(), anchor.getHeight());
+                shape.setAnchor(anchor);
 
-            assertNotNull(shape.getSvgImage());
+                assertNotNull(shape.getSvgImage());
 
-            final File tmpFile = TempFile.createTempFile("svgtest", ".pptx");
-            System.out.println(tmpFile);
-            try (FileOutputStream fos = new FileOutputStream(tmpFile)) {
-                ppt.write(fos);
-            }
+                final File tmpFile = TempFile.createTempFile("svgtest", ".pptx");
+                System.out.println(tmpFile);
+                try (FileOutputStream fos = new FileOutputStream(tmpFile)) {
+                    ppt.write(fos);
+                }
 
-            String[] args = {
+                String[] args = {
                     "-format", "png", // png,gif,jpg or null for test
                     "-slide", "-1", // -1 for all
                     "-outdir", tmpFile.getParentFile().getCanonicalPath(),
                     "-quiet",
                     tmpFile.getAbsolutePath()
-            };
-            PPTX2PNG.main(args);
-        } catch (IIOException ignore) {
-            // Ignore all ImageIO related exceptions like "Can't create output stream!"
-            // which fail often in maven builds because of missing/wrong temp directory
-        } catch (NoClassDefFoundError ignore) {
-            assumeFalse(true, "Batik doesn't work on th module-path");
+                };
+                PPTX2PNG.main(args);
+            } catch (IIOException ignored) {
+                // Ignore all ImageIO related exceptions like "Can't create output stream!"
+                // which fail often in maven builds because of missing/wrong temp directory
+            } catch (NoClassDefFoundError ignored) {
+                assumeFalse(true, "Batik doesn't work on th module-path");
+            }
         }
     }
 }
\ No newline at end of file
diff --git a/poi-ooxml/src/test/java/org/apache/poi/xssf/DeferredSXSSFITestDataProvider.java b/poi-ooxml/src/test/java/org/apache/poi/xssf/DeferredSXSSFITestDataProvider.java
index 56c5efda1f..c35db12765 100644
--- a/poi-ooxml/src/test/java/org/apache/poi/xssf/DeferredSXSSFITestDataProvider.java
+++ b/poi-ooxml/src/test/java/org/apache/poi/xssf/DeferredSXSSFITestDataProvider.java
@@ -19,6 +19,12 @@
 
 package org.apache.poi.xssf;
 
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.ArrayList;
+import java.util.Collection;
+
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.POIDataSamples;
 import org.apache.poi.ss.ITestDataProvider;
 import org.apache.poi.ss.SpreadsheetVersion;
@@ -31,13 +37,6 @@ import org.apache.poi.xssf.streaming.SXSSFWorkbook;
 import org.apache.poi.xssf.usermodel.XSSFFormulaEvaluator;
 import org.apache.poi.xssf.usermodel.XSSFWorkbook;
 
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
-import java.io.IOException;
-import java.io.InputStream;
-import java.util.ArrayList;
-import java.util.Collection;
-
 public final class DeferredSXSSFITestDataProvider implements ITestDataProvider {
     public static final DeferredSXSSFITestDataProvider instance = new DeferredSXSSFITestDataProvider();
 
@@ -69,16 +68,14 @@ public final class DeferredSXSSFITestDataProvider implements ITestDataProvider {
             throw new IllegalArgumentException("Expected an instance of XSSFWorkbook");
         }
 
-        XSSFWorkbook result;
-        try {
-            ByteArrayOutputStream baos = new ByteArrayOutputStream(8192);
+        try (UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream()) {
             wb.write(baos);
-            InputStream is = new ByteArrayInputStream(baos.toByteArray());
-            result = new XSSFWorkbook(is);
+            try (InputStream is = baos.toInputStream()) {
+                return new XSSFWorkbook(is);
+            }
         } catch (IOException e) {
             throw new RuntimeException(e);
         }
-        return result;
     }
 
     @Override
@@ -87,7 +84,7 @@ public final class DeferredSXSSFITestDataProvider implements ITestDataProvider {
         instances.add(wb);
         return wb;
     }
-    
+
     //************ SXSSF-specific methods ***************//
     @Override
     public DeferredSXSSFWorkbook createWorkbook(int rowAccessWindowSize) {
@@ -95,13 +92,13 @@ public final class DeferredSXSSFITestDataProvider implements ITestDataProvider {
         instances.add(wb);
         return wb;
     }
-    
+
     @Override
     public void trackAllColumnsForAutosizing(Sheet sheet) {
         ((DeferredSXSSFSheet)sheet).trackAllColumnsForAutoSizing();
     }
     //************ End SXSSF-specific methods ***************//
-    
+
     @Override
     public FormulaEvaluator createFormulaEvaluator(Workbook wb) {
         return new XSSFFormulaEvaluator(((DeferredSXSSFWorkbook) wb).getXSSFWorkbook());
diff --git a/poi-ooxml/src/test/java/org/apache/poi/xssf/SXSSFITestDataProvider.java b/poi-ooxml/src/test/java/org/apache/poi/xssf/SXSSFITestDataProvider.java
index 744b02beb0..8c722151ee 100644
--- a/poi-ooxml/src/test/java/org/apache/poi/xssf/SXSSFITestDataProvider.java
+++ b/poi-ooxml/src/test/java/org/apache/poi/xssf/SXSSFITestDataProvider.java
@@ -19,13 +19,12 @@
 
 package org.apache.poi.xssf;
 
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.util.ArrayList;
 import java.util.Collection;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.POIDataSamples;
 import org.apache.poi.ss.ITestDataProvider;
 import org.apache.poi.ss.SpreadsheetVersion;
@@ -68,16 +67,14 @@ public final class SXSSFITestDataProvider implements ITestDataProvider {
             throw new IllegalArgumentException("Expected an instance of SXSSFWorkbook");
         }
 
-        XSSFWorkbook result;
-        try {
-            ByteArrayOutputStream baos = new ByteArrayOutputStream(8192);
+        try (UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream()) {
             wb.write(baos);
-            InputStream is = new ByteArrayInputStream(baos.toByteArray());
-            result = new XSSFWorkbook(is);
+            try (InputStream is = baos.toInputStream()) {
+                return new XSSFWorkbook(is);
+            }
         } catch (IOException e) {
             throw new RuntimeException(e);
         }
-        return result;
     }
 
     @Override
diff --git a/poi-ooxml/src/test/java/org/apache/poi/xssf/TestXSSFMemoryLeak.java b/poi-ooxml/src/test/java/org/apache/poi/xssf/TestXSSFMemoryLeak.java
index bb9859998c..3b35c52ac9 100644
--- a/poi-ooxml/src/test/java/org/apache/poi/xssf/TestXSSFMemoryLeak.java
+++ b/poi-ooxml/src/test/java/org/apache/poi/xssf/TestXSSFMemoryLeak.java
@@ -21,13 +21,13 @@ import static org.junit.jupiter.api.Assertions.assertNull;
 import static org.junit.jupiter.api.Assertions.assertSame;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
-import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.IOException;
 import java.io.OutputStream;
 import java.util.ArrayList;
 import java.util.List;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.ooxml.POIXMLException;
 import org.apache.poi.openxml4j.exceptions.InvalidFormatException;
 import org.apache.poi.openxml4j.opc.OPCPackage;
@@ -72,7 +72,7 @@ public class TestXSSFMemoryLeak {
             // not freed until we free up the Cell itself
             //verifier.addObject(ctCell);
 
-            try (OutputStream out = new ByteArrayOutputStream(8192)) {
+            try (OutputStream out = new UnsynchronizedByteArrayOutputStream(8192)) {
                 wb.write(out);
             }
 
diff --git a/poi-ooxml/src/test/java/org/apache/poi/xssf/XSSFTestDataSamples.java b/poi-ooxml/src/test/java/org/apache/poi/xssf/XSSFTestDataSamples.java
index 6beb153bd2..3a0ed9d4c3 100644
--- a/poi-ooxml/src/test/java/org/apache/poi/xssf/XSSFTestDataSamples.java
+++ b/poi-ooxml/src/test/java/org/apache/poi/xssf/XSSFTestDataSamples.java
@@ -17,14 +17,13 @@
 
 package org.apache.poi.xssf;
 
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.hssf.HSSFTestDataSamples;
 import org.apache.poi.openxml4j.opc.OPCPackage;
 import org.apache.poi.ss.usermodel.Workbook;
@@ -62,8 +61,8 @@ public class XSSFTestDataSamples {
     }
 
     /**
-     * Write out workbook <code>wb</code> to {@link #TEST_OUTPUT_DIR}/testName.xlsx
-     * (or create a temporary file if <code>TEST_OUTPUT_DIR</code> is not defined).
+     * Write out workbook {@code wb} to {@link #TEST_OUTPUT_DIR}/testName.xlsx
+     * (or create a temporary file if {@code TEST_OUTPUT_DIR} is not defined).
      *
      * @param wb the workbook to write
      * @param testName a fragment of the filename
@@ -93,7 +92,7 @@ public class XSSFTestDataSamples {
         final File file;
         if (testOutputDir != null) {
             // In case user provided testName with a file extension, don't repeat the file extension a second time
-            final String testNameWithExtension = testName.endsWith(".xlsx") ? testName : testName + ".xlsx";
+            final String testNameWithExtension = (testName.endsWith(".xlsx") || testName.endsWith(".xlsxm")) ? testName : testName + ".xlsx";
             // FIXME: may want to defer to the TempFile with a persistent file creation strategy to the test output dir
             // This would add the random value in the middle of the filename so that test runs wouldn't overwrite files
             file = new File(testOutputDir, testNameWithExtension);
@@ -110,14 +109,14 @@ public class XSSFTestDataSamples {
     }
 
     /**
-     * Write out workbook <code>wb</code> to a memory buffer
+     * Write out workbook {@code wb} to a memory buffer
      *
      * @param wb the workbook to write
      * @return the memory buffer
      * @throws IOException If writing the file fails
      */
-    public static <R extends Workbook> ByteArrayOutputStream writeOut(R wb) throws IOException {
-        ByteArrayOutputStream out = new ByteArrayOutputStream(8192);
+    public static <R extends Workbook> UnsynchronizedByteArrayOutputStream writeOut(R wb) throws IOException {
+        UnsynchronizedByteArrayOutputStream out = new UnsynchronizedByteArrayOutputStream(8192);
         wb.write(out);
         return out;
     }
@@ -130,10 +129,10 @@ public class XSSFTestDataSamples {
      * Make sure there are no references to any objects in the workbook
      * so that garbage collection may free the workbook.
      *
-     * After calling this method, null the reference to <code>wb</code>,
+     * After calling this method, null the reference to {@code wb},
      * then call {@link #readBack(File)} or {@link #readBackAndDelete(File)} to re-read the file.
      *
-     * Alternatively, use {@link #writeOutAndClose(Workbook)} to use a ByteArrayOutputStream/ByteArrayInputStream
+     * Alternatively, use {@link #writeOutAndClose(Workbook)} to use a UnsynchronizedByteArrayOutputStream/ByteArrayInputStream
      * to avoid creating a temporary file. However, this may complicate the calling
      * code to avoid having the workbook, BAOS, and BAIS open at the same time.
      *
@@ -156,15 +155,15 @@ public class XSSFTestDataSamples {
 
 
     /**
-     * Write out workbook <code>wb</code> to a memory buffer,
+     * Write out workbook {@code wb} to a memory buffer,
      * then close the workbook
      *
      * @param wb the workbook to write
      * @return the memory buffer
      * @throws RuntimeException If writing the file fails
      */
-    public static <R extends Workbook> ByteArrayOutputStream writeOutAndClose(R wb) throws IOException {
-        ByteArrayOutputStream out = writeOut(wb);
+    public static <R extends Workbook> UnsynchronizedByteArrayOutputStream writeOutAndClose(R wb) throws IOException {
+        UnsynchronizedByteArrayOutputStream out = writeOut(wb);
         // Do not close the workbook if there was a problem writing the workbook
         wb.close();
         return out;
@@ -211,8 +210,8 @@ public class XSSFTestDataSamples {
      * @return the read back workbook
      * @throws IOException If reading the file fails
      */
-    public static XSSFWorkbook readBack(ByteArrayOutputStream out) throws IOException {
-        try (InputStream is = new ByteArrayInputStream(out.toByteArray())) {
+    public static XSSFWorkbook readBack(UnsynchronizedByteArrayOutputStream out) throws IOException {
+        try (InputStream is = out.toInputStream()) {
             out.close();
             return new XSSFWorkbook(is);
         }
@@ -226,12 +225,12 @@ public class XSSFTestDataSamples {
      * Workbook wb = new XSSFWorkbook();
      * String testName = "example";
      *
-     * <code>
+     * {@code
      * File file = writeOutAndClose(wb, testName);
      * // clear all references that would prevent the workbook from getting garbage collected
      * wb = null;
      * Workbook wbBack = readBackAndDelete(file);
-     * </code>
+     * }
      *
      * @param wb the workbook to write out
      * @return the read back workbook
diff --git a/poi-ooxml/src/test/java/org/apache/poi/xssf/extractor/TestXSSFExportToXML.java b/poi-ooxml/src/test/java/org/apache/poi/xssf/extractor/TestXSSFExportToXML.java
index e85998cb12..5672564fd0 100644
--- a/poi-ooxml/src/test/java/org/apache/poi/xssf/extractor/TestXSSFExportToXML.java
+++ b/poi-ooxml/src/test/java/org/apache/poi/xssf/extractor/TestXSSFExportToXML.java
@@ -24,7 +24,6 @@ import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.nio.charset.StandardCharsets;
 import java.util.Collection;
@@ -34,6 +33,7 @@ import java.util.regex.Pattern;
 
 import javax.xml.parsers.DocumentBuilder;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.ooxml.POIXMLDocumentPart;
 import org.apache.poi.ooxml.util.DocumentHelper;
 import org.apache.poi.ss.usermodel.Cell;
@@ -66,7 +66,7 @@ public final class TestXSSFExportToXML {
 
                 XSSFMap map = mapInfo.getXSSFMapById(1);
                 XSSFExportToXml exporter = new XSSFExportToXml(map);
-                ByteArrayOutputStream os = new ByteArrayOutputStream();
+                UnsynchronizedByteArrayOutputStream os = new UnsynchronizedByteArrayOutputStream();
                 exporter.exportToXML(os, true);
                 String xml = os.toString("UTF-8");
 
@@ -114,7 +114,7 @@ public final class TestXSSFExportToXML {
 
                 XSSFMap map = mapInfo.getXSSFMapById(1);
                 XSSFExportToXml exporter = new XSSFExportToXml(map);
-                ByteArrayOutputStream os = new ByteArrayOutputStream();
+                UnsynchronizedByteArrayOutputStream os = new UnsynchronizedByteArrayOutputStream();
                 exporter.exportToXML(os, true);
                 String xml = os.toString("UTF-8");
 
@@ -187,7 +187,7 @@ public final class TestXSSFExportToXML {
                     assertNotNull(map);
 
                     XSSFExportToXml exporter = new XSSFExportToXml(map);
-                    ByteArrayOutputStream os = new ByteArrayOutputStream();
+                    UnsynchronizedByteArrayOutputStream os = new UnsynchronizedByteArrayOutputStream();
                     exporter.exportToXML(os, true);
                     String xml = os.toString("UTF-8");
 
@@ -223,7 +223,7 @@ public final class TestXSSFExportToXML {
             for (XSSFMap map : wb.getCustomXMLMappings()) {
                 XSSFExportToXml exporter = new XSSFExportToXml(map);
 
-                ByteArrayOutputStream os = new ByteArrayOutputStream();
+                UnsynchronizedByteArrayOutputStream os = new UnsynchronizedByteArrayOutputStream();
                 exporter.exportToXML(os, true);
             }
         }
@@ -246,7 +246,7 @@ public final class TestXSSFExportToXML {
                 assertNotNull(map, "XSSFMap is null");
 
                 XSSFExportToXml exporter = new XSSFExportToXml(map);
-                ByteArrayOutputStream os = new ByteArrayOutputStream();
+                UnsynchronizedByteArrayOutputStream os = new UnsynchronizedByteArrayOutputStream();
                 exporter.exportToXML(os, true);
                 String xmlData = os.toString("UTF-8");
 
@@ -290,7 +290,7 @@ public final class TestXSSFExportToXML {
                 assertNotNull(map, "XSSFMap is null");
 
                 XSSFExportToXml exporter = new XSSFExportToXml(map);
-                ByteArrayOutputStream os = new ByteArrayOutputStream();
+                UnsynchronizedByteArrayOutputStream os = new UnsynchronizedByteArrayOutputStream();
                 exporter.exportToXML(os, true);
                 String xmlData = os.toString("UTF-8");
 
@@ -325,7 +325,7 @@ public final class TestXSSFExportToXML {
                 assertNotNull(map, "XSSFMap is null");
 
                 XSSFExportToXml exporter = new XSSFExportToXml(map);
-                ByteArrayOutputStream os = new ByteArrayOutputStream();
+                UnsynchronizedByteArrayOutputStream os = new UnsynchronizedByteArrayOutputStream();
                 exporter.exportToXML(os, true);
                 String xmlData = os.toString("UTF-8");
 
@@ -364,7 +364,7 @@ public final class TestXSSFExportToXML {
                 assertNotNull(map, "XSSFMap is null");
 
                 XSSFExportToXml exporter = new XSSFExportToXml(map);
-                ByteArrayOutputStream os = new ByteArrayOutputStream();
+                UnsynchronizedByteArrayOutputStream os = new UnsynchronizedByteArrayOutputStream();
                 exporter.exportToXML(os, true);
                 String xmlData = os.toString("UTF-8");
 
@@ -390,7 +390,7 @@ public final class TestXSSFExportToXML {
             for (XSSFMap map : wb.getCustomXMLMappings()) {
                 XSSFExportToXml exporter = new XSSFExportToXml(map);
 
-                ByteArrayOutputStream os = new ByteArrayOutputStream();
+                UnsynchronizedByteArrayOutputStream os = new UnsynchronizedByteArrayOutputStream();
                 exporter.exportToXML(os, true);
                 String xmlData = os.toString("UTF-8");
 
@@ -468,7 +468,7 @@ public final class TestXSSFExportToXML {
                 assertNotNull(map, "XSSFMap is null");
 
                 XSSFExportToXml exporter = new XSSFExportToXml(map);
-                ByteArrayOutputStream os = new ByteArrayOutputStream();
+                UnsynchronizedByteArrayOutputStream os = new UnsynchronizedByteArrayOutputStream();
                 exporter.exportToXML(os, true);
                 String xmlData = os.toString("UTF-8");
 
@@ -546,7 +546,7 @@ public final class TestXSSFExportToXML {
                 assertNotNull(map, "XSSFMap is null");
 
                 XSSFExportToXml exporter = new XSSFExportToXml(map);
-                ByteArrayOutputStream os = new ByteArrayOutputStream();
+                UnsynchronizedByteArrayOutputStream os = new UnsynchronizedByteArrayOutputStream();
                 exporter.exportToXML(os, true);
                 String xmlData = os.toString("UTF-8");
 
@@ -577,7 +577,7 @@ public final class TestXSSFExportToXML {
                 assertNotNull(map, "XSSFMap is null");
 
                 XSSFExportToXml exporter = new XSSFExportToXml(map);
-                ByteArrayOutputStream os = new ByteArrayOutputStream();
+                UnsynchronizedByteArrayOutputStream os = new UnsynchronizedByteArrayOutputStream();
                 exporter.exportToXML(os, false);
                 String xmlData = os.toString("UTF-8");
 
@@ -609,7 +609,7 @@ public final class TestXSSFExportToXML {
                 assertNotNull(map, "XSSFMap is null");
 
                 XSSFExportToXml exporter = new XSSFExportToXml(map);
-                ByteArrayOutputStream os = new ByteArrayOutputStream();
+                UnsynchronizedByteArrayOutputStream os = new UnsynchronizedByteArrayOutputStream();
                 exporter.exportToXML(os, true);
                 String xmlData = os.toString("UTF-8");
 
@@ -635,7 +635,7 @@ public final class TestXSSFExportToXML {
             for (XSSFMap map : mappings) {
                 XSSFExportToXml exporter = new XSSFExportToXml(map);
 
-                ByteArrayOutputStream os = new ByteArrayOutputStream();
+                UnsynchronizedByteArrayOutputStream os = new UnsynchronizedByteArrayOutputStream();
                 exporter.exportToXML(os, false);
                 assertNotNull(os.toString("UTF-8"));
             }
@@ -647,9 +647,9 @@ public final class TestXSSFExportToXML {
         try (XSSFWorkbook wb = XSSFTestDataSamples.openSampleWorkbook("61281.xlsx")) {
             for (XSSFMap map : wb.getCustomXMLMappings()) {
                 XSSFExportToXml exporter = new XSSFExportToXml(map);
-                ByteArrayOutputStream bos = new ByteArrayOutputStream();
+                UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream();
                 exporter.exportToXML(bos, true);
-                assertNotNull(DocumentHelper.readDocument(new ByteArrayInputStream(bos.toByteArray())));
+                assertNotNull(DocumentHelper.readDocument(bos.toInputStream()));
                 String exportedXml = bos.toString("UTF-8");
                 assertEquals("<Test><Test>1</Test></Test>", exportedXml.replaceAll("\\s+", ""));
             }
@@ -661,7 +661,7 @@ public final class TestXSSFExportToXML {
         try (XSSFWorkbook wb = XSSFTestDataSamples.openSampleWorkbook("xxe_in_schema.xlsx")) {
             for (XSSFMap map : wb.getCustomXMLMappings()) {
                 XSSFExportToXml exporter = new XSSFExportToXml(map);
-                ByteArrayOutputStream bos = new ByteArrayOutputStream();
+                UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream();
                 assertThrows(SAXParseException.class, () -> exporter.exportToXML(bos, true));
             }
         }
diff --git a/poi-ooxml/src/test/java/org/apache/poi/xssf/streaming/TestSXSSFWorkbook.java b/poi-ooxml/src/test/java/org/apache/poi/xssf/streaming/TestSXSSFWorkbook.java
index e065b26adb..17c4eec074 100644
--- a/poi-ooxml/src/test/java/org/apache/poi/xssf/streaming/TestSXSSFWorkbook.java
+++ b/poi-ooxml/src/test/java/org/apache/poi/xssf/streaming/TestSXSSFWorkbook.java
@@ -19,6 +19,7 @@
 
 package org.apache.poi.xssf.streaming;
 
+import static org.apache.commons.io.output.NullOutputStream.NULL_OUTPUT_STREAM;
 import static org.apache.poi.POITestCase.assertEndsWith;
 import static org.apache.poi.POITestCase.assertStartsWith;
 import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
@@ -29,14 +30,13 @@ import static org.junit.jupiter.api.Assertions.assertSame;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.util.Arrays;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.POIDataSamples;
 import org.apache.poi.openxml4j.opc.OPCPackage;
 import org.apache.poi.openxml4j.opc.PackageAccess;
@@ -48,7 +48,6 @@ import org.apache.poi.ss.usermodel.Sheet;
 import org.apache.poi.ss.usermodel.Workbook;
 import org.apache.poi.ss.usermodel.WorkbookFactory;
 import org.apache.poi.ss.util.CellReference;
-import org.apache.poi.util.NullOutputStream;
 import org.apache.poi.xssf.SXSSFITestDataProvider;
 import org.apache.poi.xssf.XSSFTestDataSamples;
 import org.apache.poi.xssf.model.SharedStringsTable;
@@ -74,7 +73,7 @@ public final class TestSXSSFWorkbook extends BaseTestXWorkbook {
     @Override
     @Test
     protected void cloneSheet() throws IOException {
-        RuntimeException e = assertThrows(RuntimeException.class, () -> super.cloneSheet());
+        RuntimeException e = assertThrows(RuntimeException.class, super::cloneSheet);
         assertEquals("Not Implemented", e.getMessage());
     }
 
@@ -84,7 +83,7 @@ public final class TestSXSSFWorkbook extends BaseTestXWorkbook {
     @Override
     @Test
     protected void sheetClone() {
-        RuntimeException e = assertThrows(RuntimeException.class, () -> super.sheetClone());
+        RuntimeException e = assertThrows(RuntimeException.class, super::sheetClone);
         assertEquals("Not Implemented", e.getMessage());
     }
 
@@ -407,8 +406,8 @@ public final class TestSXSSFWorkbook extends BaseTestXWorkbook {
 
     private static void saveTwice(Workbook wb) throws Exception {
         for (int i = 0; i < 2; i++) {
-            try (NullOutputStream out = new NullOutputStream()) {
-                wb.write(out);
+            try {
+                wb.write(NULL_OUTPUT_STREAM);
             } catch (Exception e) {
                 throw new Exception("ERROR: failed on " + (i + 1)
                         + "th time calling " + wb.getClass().getName()
@@ -471,7 +470,7 @@ public final class TestSXSSFWorkbook extends BaseTestXWorkbook {
                 }
             }
 
-            assertDoesNotThrow(() -> swb.write(new NullOutputStream()));
+            assertDoesNotThrow(() -> swb.write(NULL_OUTPUT_STREAM));
             swb.dispose();
         }
     }
@@ -489,7 +488,7 @@ public final class TestSXSSFWorkbook extends BaseTestXWorkbook {
         File input = XSSFTestDataSamples.getSampleFile("sample.xlsx");
 
         try (OPCPackage pkg = OPCPackage.open(input, PackageAccess.READ)) {
-            ByteArrayOutputStream bos = new ByteArrayOutputStream();
+            UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream();
             try (XSSFWorkbook xssf = new XSSFWorkbook(pkg)) {
                 try (SXSSFWorkbook wb = new SXSSFWorkbook(xssf, 2)) {
                     Sheet s = wb.createSheet(sheetName);
@@ -506,7 +505,7 @@ public final class TestSXSSFWorkbook extends BaseTestXWorkbook {
                 }
             }
 
-            try (XSSFWorkbook xssf = new XSSFWorkbook(new ByteArrayInputStream(bos.toByteArray()))) {
+            try (XSSFWorkbook xssf = new XSSFWorkbook(bos.toInputStream())) {
                 Sheet s = xssf.getSheet(sheetName);
                 assertEquals(10, s.getLastRowNum());
                 assertTrue(s.getRow(0).getCell(0).getBooleanCellValue());
@@ -518,20 +517,17 @@ public final class TestSXSSFWorkbook extends BaseTestXWorkbook {
 
     @Test
     void test56557() throws IOException {
-        Workbook wb = XSSFTestDataSamples.openSampleWorkbook("56557.xlsx");
-
-        // Using streaming XSSFWorkbook makes the output file invalid
-        wb = new SXSSFWorkbook(((XSSFWorkbook) wb));
-
-        // Should not throw POIXMLException: java.io.IOException: Unable to parse xml bean when reading back
-        Workbook wbBack = XSSFTestDataSamples.writeOutAndReadBack(wb);
-        assertNotNull(wbBack);
-        wbBack.close();
-
-        wb.close();
+        try (XSSFWorkbook wb = XSSFTestDataSamples.openSampleWorkbook("56557.xlsx");
+             // Using streaming XSSFWorkbook makes the output file invalid
+             Workbook wb2 = new SXSSFWorkbook(wb);
+             // Should not throw POIXMLException: java.io.IOException: Unable to parse xml bean when reading back
+             Workbook wbBack = XSSFTestDataSamples.writeOutAndReadBack(wb2)
+         ) {
+            assertNotNull(wbBack);
+        }
     }
 
+    @Disabled("not implemented")
     void changeSheetNameWithSharedFormulas() {
-        /* not implemented */
     }
 }
diff --git a/poi-ooxml/src/test/java/org/apache/poi/xssf/streaming/TestSXSSFWorkbookWithCustomZipEntrySource.java b/poi-ooxml/src/test/java/org/apache/poi/xssf/streaming/TestSXSSFWorkbookWithCustomZipEntrySource.java
index b1fa40fe69..d5afe8ea15 100644
--- a/poi-ooxml/src/test/java/org/apache/poi/xssf/streaming/TestSXSSFWorkbookWithCustomZipEntrySource.java
+++ b/poi-ooxml/src/test/java/org/apache/poi/xssf/streaming/TestSXSSFWorkbookWithCustomZipEntrySource.java
@@ -20,12 +20,11 @@
 package org.apache.poi.xssf.streaming;
 
 import static java.nio.charset.StandardCharsets.UTF_8;
+import static org.apache.commons.io.output.NullOutputStream.NULL_OUTPUT_STREAM;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.IOException;
@@ -33,6 +32,7 @@ import java.io.InputStream;
 import java.io.OutputStream;
 import java.util.List;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.openxml4j.exceptions.InvalidFormatException;
 import org.apache.poi.openxml4j.opc.OPCPackage;
 import org.apache.poi.openxml4j.util.ZipEntrySource;
@@ -58,38 +58,40 @@ public final class TestSXSSFWorkbookWithCustomZipEntrySource {
     // write an unencrypted workbook to disk, but any temporary files are encrypted
     @Test
     void customZipEntrySource() throws IOException {
-        SXSSFWorkbookWithCustomZipEntrySource workbook = new SXSSFWorkbookWithCustomZipEntrySource();
-        SXSSFSheet sheet1 = workbook.createSheet(sheetName);
-        SXSSFRow row1 = sheet1.createRow(1);
-        SXSSFCell cell1 = row1.createCell(1);
-        cell1.setCellValue(cellValue);
-        ByteArrayOutputStream os = new ByteArrayOutputStream(8192);
-        workbook.write(os);
-        workbook.close();
-        workbook.dispose();
-        XSSFWorkbook xwb = new XSSFWorkbook(new ByteArrayInputStream(os.toByteArray()));
-        XSSFSheet xs1 = xwb.getSheetAt(0);
-        assertEquals(sheetName, xs1.getSheetName());
-        XSSFRow xr1 = xs1.getRow(1);
-        XSSFCell xc1 = xr1.getCell(1);
-        assertEquals(cellValue, xc1.getStringCellValue());
-        xwb.close();
+        UnsynchronizedByteArrayOutputStream os = new UnsynchronizedByteArrayOutputStream(8192);
+        try (SXSSFWorkbookWithCustomZipEntrySource workbook = new SXSSFWorkbookWithCustomZipEntrySource()) {
+            SXSSFSheet sheet1 = workbook.createSheet(sheetName);
+            SXSSFRow row1 = sheet1.createRow(1);
+            SXSSFCell cell1 = row1.createCell(1);
+            cell1.setCellValue(cellValue);
+            workbook.write(os);
+            workbook.close();
+            workbook.dispose();
+        }
+        try (XSSFWorkbook xwb = new XSSFWorkbook(os.toInputStream())) {
+            XSSFSheet xs1 = xwb.getSheetAt(0);
+            assertEquals(sheetName, xs1.getSheetName());
+            XSSFRow xr1 = xs1.getRow(1);
+            XSSFCell xc1 = xr1.getCell(1);
+            assertEquals(cellValue, xc1.getStringCellValue());
+        }
     }
 
     // write an encrypted workbook to disk, and encrypt any temporary files as well
     @Test
     void customZipEntrySourceForWriteAndRead() throws IOException, InvalidFormatException {
-        SXSSFWorkbookWithCustomZipEntrySource workbook = new SXSSFWorkbookWithCustomZipEntrySource();
-        SXSSFSheet sheet1 = workbook.createSheet(sheetName);
-        SXSSFRow row1 = sheet1.createRow(1);
-        SXSSFCell cell1 = row1.createCell(1);
-        cell1.setCellValue(cellValue);
         EncryptedTempData tempData = new EncryptedTempData();
-        try (OutputStream os = tempData.getOutputStream()) {
-            workbook.write(os);
+        try (SXSSFWorkbookWithCustomZipEntrySource workbook = new SXSSFWorkbookWithCustomZipEntrySource()) {
+            SXSSFSheet sheet1 = workbook.createSheet(sheetName);
+            SXSSFRow row1 = sheet1.createRow(1);
+            SXSSFCell cell1 = row1.createCell(1);
+            cell1.setCellValue(cellValue);
+            try (OutputStream os = tempData.getOutputStream()) {
+                workbook.write(os);
+            }
+            workbook.close();
+            workbook.dispose();
         }
-        workbook.close();
-        workbook.dispose();
         try (InputStream is = tempData.getInputStream();
              ZipEntrySource zipEntrySource = AesZipFileZipEntrySource.createZipEntrySource(is)) {
             tempData.dispose();
@@ -111,8 +113,7 @@ public final class TestSXSSFWorkbookWithCustomZipEntrySource {
         SXSSFRow row1 = sheet1.createRow(1);
         SXSSFCell cell1 = row1.createCell(1);
         cell1.setCellValue(cellValue);
-        ByteArrayOutputStream os = new ByteArrayOutputStream(8192);
-        workbook.write(os);
+        workbook.write(NULL_OUTPUT_STREAM);
         workbook.close();
         List<File> tempFiles = workbook.getTempFiles();
         assertEquals(1, tempFiles.size());
diff --git a/poi-ooxml/src/test/java/org/apache/poi/xssf/usermodel/TestUnfixedBugs.java b/poi-ooxml/src/test/java/org/apache/poi/xssf/usermodel/TestUnfixedBugs.java
index 679c3c60bf..0b307277f5 100644
--- a/poi-ooxml/src/test/java/org/apache/poi/xssf/usermodel/TestUnfixedBugs.java
+++ b/poi-ooxml/src/test/java/org/apache/poi/xssf/usermodel/TestUnfixedBugs.java
@@ -17,6 +17,7 @@
 
 package org.apache.poi.xssf.usermodel;
 
+import static org.apache.poi.xssf.XSSFTestDataSamples.writeOutAndReadBack;
 import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
@@ -24,13 +25,13 @@ import static org.junit.jupiter.api.Assertions.assertNull;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 import static org.junit.jupiter.api.Assertions.fail;
 
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.nio.charset.StandardCharsets;
 import java.util.Calendar;
 import java.util.Date;
 import java.util.Hashtable;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.ss.formula.OperationEvaluationContext;
 import org.apache.poi.ss.formula.eval.NumberEval;
 import org.apache.poi.ss.formula.eval.ValueEval;
@@ -242,7 +243,7 @@ public final class TestUnfixedBugs {
 
         checkRows57423(testSheet);
 
-        Workbook wbBack = XSSFTestDataSamples.writeOutAndReadBack(wb);
+        Workbook wbBack = writeOutAndReadBack(wb);
         /* XSSFTestDataSamples.writeOut(wb, "bug 57423 for manual review"); */
 
         wb.close();
@@ -277,12 +278,8 @@ public final class TestUnfixedBugs {
         checkRow57423(testSheet, 17, "17");
         checkRow57423(testSheet, 18, "18");
 
-        ByteArrayOutputStream stream = new ByteArrayOutputStream();
-        try {
-            ((XSSFSheet)testSheet).write(stream);
-        } finally {
-            stream.close();
-        }
+        UnsynchronizedByteArrayOutputStream stream = new UnsynchronizedByteArrayOutputStream();
+        ((XSSFSheet)testSheet).write(stream);
 
         // verify that the resulting XML has the rows in correct order as required by Excel
         String xml = new String(stream.toByteArray(), StandardCharsets.UTF_8);
@@ -310,27 +307,21 @@ public final class TestUnfixedBugs {
 
     @Test
     void bug57423_shiftRowsByLargeOffset() throws IOException {
-        try (
-                XSSFWorkbook wb = new XSSFWorkbook()
-                //OutputStream out = new FileOutputStream("/tmp/57423." + wb.getClass().getName() + ".xlsx"));
-        ) {
+        try (XSSFWorkbook wb = new XSSFWorkbook()) {
             Sheet sh = wb.createSheet();
             sh.createRow(0).createCell(0).setCellValue("a");
             sh.createRow(1).createCell(0).setCellValue("b");
             sh.createRow(2).createCell(0).setCellValue("c");
             sh.shiftRows(0, 1, 3);
 
-            XSSFWorkbook wbBack = XSSFTestDataSamples.writeOutAndReadBack(wb);
-
-            assertThatRowsInAscendingOrder(wb);
-            assertThatRowsInAscendingOrder(wbBack);
-
-            //wbBack.write(out);
-            // Excel reports that the workbook is corrupt because the rows are not in ascending order
-            // LibreOffice doesn't complain when rows are not in ascending order
-
-            wbBack.close();
+            try (XSSFWorkbook wbBack = writeOutAndReadBack(wb)) {
+                assertThatRowsInAscendingOrder(wb);
+                assertThatRowsInAscendingOrder(wbBack);
 
+                //wbBack.write(out);
+                // Excel reports that the workbook is corrupt because the rows are not in ascending order
+                // LibreOffice doesn't complain when rows are not in ascending order
+            }
             fail("Excel reports that the workbook is corrupt, LibreOffice can read it");
         }
     }
diff --git a/poi-ooxml/src/test/java/org/apache/poi/xssf/usermodel/TestXSSFBugs.java b/poi-ooxml/src/test/java/org/apache/poi/xssf/usermodel/TestXSSFBugs.java
index d0d97e91de..508362e820 100644
--- a/poi-ooxml/src/test/java/org/apache/poi/xssf/usermodel/TestXSSFBugs.java
+++ b/poi-ooxml/src/test/java/org/apache/poi/xssf/usermodel/TestXSSFBugs.java
@@ -19,20 +19,20 @@ package org.apache.poi.xssf.usermodel;
 
 import static java.time.Duration.between;
 import static java.time.Instant.now;
+import static org.apache.commons.io.output.NullOutputStream.NULL_OUTPUT_STREAM;
 import static org.apache.logging.log4j.util.Unbox.box;
 import static org.apache.poi.extractor.ExtractorFactory.OOXML_PACKAGE;
 import static org.apache.poi.openxml4j.opc.TestContentType.isOldXercesActive;
+import static org.apache.poi.xssf.XSSFTestDataSamples.openSampleWorkbook;
+import static org.apache.poi.xssf.XSSFTestDataSamples.writeOutAndReadBack;
 import static org.junit.jupiter.api.Assertions.*;
 import static org.junit.jupiter.api.Assumptions.assumeFalse;
 
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
-import java.io.OutputStream;
 import java.nio.charset.StandardCharsets;
 import java.time.Instant;
 import java.util.Arrays;
@@ -47,6 +47,7 @@ import java.util.TreeMap;
 
 import org.apache.commons.compress.archivers.zip.ZipArchiveEntry;
 import org.apache.commons.compress.archivers.zip.ZipFile;
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.poi.POIDataSamples;
@@ -99,7 +100,7 @@ import org.apache.poi.ss.util.CellRangeAddress;
 import org.apache.poi.ss.util.CellReference;
 import org.apache.poi.ss.util.CellUtil;
 import org.apache.poi.util.LocaleUtil;
-import org.apache.poi.util.NullOutputStream;
+import org.apache.commons.io.output.NullOutputStream;
 import org.apache.poi.util.TempFile;
 import org.apache.poi.util.XMLHelper;
 import org.apache.poi.xssf.SXSSFITestDataProvider;
@@ -115,6 +116,7 @@ import org.junit.jupiter.api.Test;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.CsvSource;
 import org.junit.jupiter.params.provider.EnumSource;
+import org.junit.jupiter.params.provider.ValueSource;
 import org.openxmlformats.schemas.spreadsheetml.x2006.main.CTCalcCell;
 import org.openxmlformats.schemas.spreadsheetml.x2006.main.CTCols;
 import org.openxmlformats.schemas.spreadsheetml.x2006.main.CTDefinedName;
@@ -140,7 +142,7 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
      */
     @Test
     void bug45430() throws IOException {
-        try (XSSFWorkbook wb = XSSFTestDataSamples.openSampleWorkbook("45430.xlsx")) {
+        try (XSSFWorkbook wb = openSampleWorkbook("45430.xlsx")) {
             assertFalse(wb.isMacroEnabled());
             assertEquals(3, wb.getNumberOfNames());
 
@@ -160,7 +162,7 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
             assertEquals("SheetC", wb.getName("SheetCA1").getSheetName());
 
             // Save and re-load, still there
-            try (XSSFWorkbook nwb = XSSFTestDataSamples.writeOutAndReadBack(wb)) {
+            try (XSSFWorkbook nwb = writeOutAndReadBack(wb)) {
                 assertEquals(3, nwb.getNumberOfNames());
                 assertEquals("SheetA!$A$1", nwb.getName("SheetAA1").getRefersToFormula());
             }
@@ -172,79 +174,74 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
      */
     @Test
     void bug45431() throws IOException, InvalidFormatException {
-        XSSFWorkbook wb1 = XSSFTestDataSamples.openSampleWorkbook("45431.xlsm");
-        OPCPackage pkg1 = wb1.getPackage();
-        assertTrue(wb1.isMacroEnabled());
+        try (XSSFWorkbook wb1 = openSampleWorkbook("45431.xlsm");
+             OPCPackage pkg1 = wb1.getPackage()) {
+            assertTrue(wb1.isMacroEnabled());
 
-        // Check the various macro related bits can be found
-        PackagePart vba = pkg1.getPart(
+            // Check the various macro related bits can be found
+            PackagePart vba = pkg1.getPart(
                 PackagingURIHelper.createPartName("/xl/vbaProject.bin")
-        );
-        assertNotNull(vba);
-        // And the drawing bit
-        PackagePart drw = pkg1.getPart(
+            );
+            assertNotNull(vba);
+            // And the drawing bit
+            PackagePart drw = pkg1.getPart(
                 PackagingURIHelper.createPartName("/xl/drawings/vmlDrawing1.vml")
-        );
-        assertNotNull(drw);
-
-
-        // Save and re-open, both still there
-        XSSFWorkbook wb2 = XSSFTestDataSamples.writeOutAndReadBack(wb1);
-        pkg1.close();
-        wb1.close();
-
-        OPCPackage pkg2 = wb2.getPackage();
-        assertTrue(wb2.isMacroEnabled());
-
-        vba = pkg2.getPart(
-                PackagingURIHelper.createPartName("/xl/vbaProject.bin")
-        );
-        assertNotNull(vba);
-        drw = pkg2.getPart(
-                PackagingURIHelper.createPartName("/xl/drawings/vmlDrawing1.vml")
-        );
-        assertNotNull(drw);
-
-        // And again, just to be sure
-        XSSFWorkbook wb3 = XSSFTestDataSamples.writeOutAndReadBack(wb2);
-        pkg2.close();
-        wb2.close();
-        OPCPackage pkg3 = wb3.getPackage();
-        assertTrue(wb3.isMacroEnabled());
-
-        vba = pkg3.getPart(
-                PackagingURIHelper.createPartName("/xl/vbaProject.bin")
-        );
-        assertNotNull(vba);
-        drw = pkg3.getPart(
-                PackagingURIHelper.createPartName("/xl/drawings/vmlDrawing1.vml")
-        );
-        assertNotNull(drw);
-
-        pkg3.close();
-        wb3.close();
+            );
+            assertNotNull(drw);
+
+
+            // Save and re-open, both still there
+            try (XSSFWorkbook wb2 = writeOutAndReadBack(wb1);
+                 OPCPackage pkg2 = wb2.getPackage()) {
+                assertTrue(wb2.isMacroEnabled());
+
+                vba = pkg2.getPart(
+                    PackagingURIHelper.createPartName("/xl/vbaProject.bin")
+                );
+                assertNotNull(vba);
+                drw = pkg2.getPart(
+                    PackagingURIHelper.createPartName("/xl/drawings/vmlDrawing1.vml")
+                );
+                assertNotNull(drw);
+
+                // And again, just to be sure
+                try (XSSFWorkbook wb3 = writeOutAndReadBack(wb2);
+                     OPCPackage pkg3 = wb3.getPackage()) {
+                    assertTrue(wb3.isMacroEnabled());
+
+                    vba = pkg3.getPart(
+                        PackagingURIHelper.createPartName("/xl/vbaProject.bin")
+                    );
+                    assertNotNull(vba);
+                    drw = pkg3.getPart(
+                        PackagingURIHelper.createPartName("/xl/drawings/vmlDrawing1.vml")
+                    );
+                    assertNotNull(drw);
+                }
+            }
+        }
     }
 
     @Test
     void bug47504() throws IOException {
-        XSSFWorkbook wb1 = XSSFTestDataSamples.openSampleWorkbook("47504.xlsx");
-        assertEquals(1, wb1.getNumberOfSheets());
-        XSSFSheet sh = wb1.getSheetAt(0);
-        XSSFDrawing drawing = sh.createDrawingPatriarch();
-        List<RelationPart> rels = drawing.getRelationParts();
-        assertEquals(1, rels.size());
-        assertEquals("Sheet1!A1", rels.get(0).getRelationship().getTargetURI().getFragment());
-
-        // And again, just to be sure
-        XSSFWorkbook wb2 = XSSFTestDataSamples.writeOutAndReadBack(wb1);
-        wb1.close();
-        assertEquals(1, wb2.getNumberOfSheets());
-        sh = wb2.getSheetAt(0);
-        drawing = sh.createDrawingPatriarch();
-        rels = drawing.getRelationParts();
-        assertEquals(1, rels.size());
-        assertEquals("Sheet1!A1", rels.get(0).getRelationship().getTargetURI().getFragment());
-        wb2.close();
+        try (XSSFWorkbook wb1 = openSampleWorkbook("47504.xlsx")) {
+            assertEquals(1, wb1.getNumberOfSheets());
+            XSSFSheet sh = wb1.getSheetAt(0);
+            XSSFDrawing drawing = sh.createDrawingPatriarch();
+            List<RelationPart> rels = drawing.getRelationParts();
+            assertEquals(1, rels.size());
+            assertEquals("Sheet1!A1", rels.get(0).getRelationship().getTargetURI().getFragment());
+
+            // And again, just to be sure
+            try (XSSFWorkbook wb2 = writeOutAndReadBack(wb1)) {
+                assertEquals(1, wb2.getNumberOfSheets());
+                sh = wb2.getSheetAt(0);
+                drawing = sh.createDrawingPatriarch();
+                rels = drawing.getRelationParts();
+                assertEquals(1, rels.size());
+                assertEquals("Sheet1!A1", rels.get(0).getRelationship().getTargetURI().getFragment());
+            }
+        }
     }
 
     /**
@@ -255,7 +252,7 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
      */
     @Test
     void bug49020() throws IOException {
-        try (XSSFWorkbook wb = XSSFTestDataSamples.openSampleWorkbook("BrNotClosed.xlsx")) {
+        try (XSSFWorkbook wb = openSampleWorkbook("BrNotClosed.xlsx")) {
             assertNotNull(wb);
         }
     }
@@ -265,7 +262,7 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
      */
     @Test
     void bug49325() throws IOException {
-        try (XSSFWorkbook wb = XSSFTestDataSamples.openSampleWorkbook("49325.xlsx")) {
+        try (XSSFWorkbook wb = openSampleWorkbook("49325.xlsx")) {
             CTWorksheet sh = wb.getSheetAt(0).getCTWorksheet();
             assertNotNull(sh.getPhoneticPr());
         }
@@ -277,7 +274,7 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
      */
     @Test
     void bug48923() throws IOException {
-        try (XSSFWorkbook wb = XSSFTestDataSamples.openSampleWorkbook("48923.xlsx")) {
+        try (XSSFWorkbook wb = openSampleWorkbook("48923.xlsx")) {
             assertEquals(4, wb.getNumberOfNames());
 
             Name b1 = wb.getName("NameB1");
@@ -321,7 +318,7 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
      */
     @Test
     void bug48539() throws IOException {
-        try (XSSFWorkbook wb = XSSFTestDataSamples.openSampleWorkbook("48539.xlsx")) {
+        try (XSSFWorkbook wb = openSampleWorkbook("48539.xlsx")) {
             assertEquals(3, wb.getNumberOfSheets());
             assertEquals(0, wb.getNumberOfNames());
 
@@ -358,7 +355,7 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
      */
     @Test
     void bug48779() throws IOException {
-        try (XSSFWorkbook wb = XSSFTestDataSamples.openSampleWorkbook("48779.xlsx")) {
+        try (XSSFWorkbook wb = openSampleWorkbook("48779.xlsx")) {
             XSSFCell cell = wb.getSheetAt(0).getRow(0).getCell(0);
             XSSFCellStyle cs = cell.getCellStyle();
 
@@ -396,7 +393,7 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
      */
     @Test
     void bug47490() throws IOException {
-        try (XSSFWorkbook wb = XSSFTestDataSamples.openSampleWorkbook("GeneralFormatTests.xlsx")) {
+        try (XSSFWorkbook wb = openSampleWorkbook("GeneralFormatTests.xlsx")) {
             Sheet s = wb.getSheetAt(1);
             Row r;
             DataFormatter df = new DataFormatter();
@@ -434,7 +431,7 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
      */
     @Test
     void bug49609() throws IOException {
-        try (XSSFWorkbook wb = XSSFTestDataSamples.openSampleWorkbook("49609.xlsx")) {
+        try (XSSFWorkbook wb = openSampleWorkbook("49609.xlsx")) {
             assertEquals("FAM", wb.getSheetName(0));
             assertEquals("Cycle", wb.getSheetAt(0).getRow(0).getCell(1).getStringCellValue());
         }
@@ -443,7 +440,7 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
 
     @Test
     void bug49783() throws IOException {
-        try (Workbook wb = XSSFTestDataSamples.openSampleWorkbook("49783.xlsx")) {
+        try (Workbook wb = openSampleWorkbook("49783.xlsx")) {
             Sheet sheet = wb.getSheetAt(0);
             FormulaEvaluator evaluator = wb.getCreationHelper().createFormulaEvaluator();
             Cell cell;
@@ -476,78 +473,77 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
      */
     @Test
     void bug49941() throws IOException {
-        XSSFWorkbook wb1 = new XSSFWorkbook();
-        XSSFSheet s = wb1.createSheet();
-        XSSFRow r = s.createRow(0);
-        XSSFCell c = r.createCell(0);
+        try (XSSFWorkbook wb1 = new XSSFWorkbook()) {
+            XSSFSheet s = wb1.createSheet();
+            XSSFRow r = s.createRow(0);
+            XSSFCell c = r.createCell(0);
 
-        // First without fonts
-        c.setCellValue(
+            // First without fonts
+            c.setCellValue(
                 new XSSFRichTextString(" with spaces ")
-        );
-        assertEquals(" with spaces ", c.getRichStringCellValue().toString());
-        assertEquals(0, c.getRichStringCellValue().getCTRst().sizeOfRArray());
-        assertTrue(c.getRichStringCellValue().getCTRst().isSetT());
-        // Should have the preserve set
-        assertEquals(
+            );
+            assertEquals(" with spaces ", c.getRichStringCellValue().toString());
+            assertEquals(0, c.getRichStringCellValue().getCTRst().sizeOfRArray());
+            assertTrue(c.getRichStringCellValue().getCTRst().isSetT());
+            // Should have the preserve set
+            assertEquals(
                 1,
                 c.getRichStringCellValue().getCTRst().xgetT().getDomNode().getAttributes().getLength()
-        );
-        assertEquals(
+            );
+            assertEquals(
                 "preserve",
                 c.getRichStringCellValue().getCTRst().xgetT().getDomNode().getAttributes().item(0).getNodeValue()
-        );
-
-        // Save and check
-        XSSFWorkbook wb2 = XSSFTestDataSamples.writeOutAndReadBack(wb1);
-        wb1.close();
-        s = wb2.getSheetAt(0);
-        r = s.getRow(0);
-        c = r.getCell(0);
-        assertEquals(" with spaces ", c.getRichStringCellValue().toString());
-        assertEquals(0, c.getRichStringCellValue().getCTRst().sizeOfRArray());
-        assertTrue(c.getRichStringCellValue().getCTRst().isSetT());
-
-        // Change the string
-        c.setCellValue(
-                new XSSFRichTextString("hello world")
-        );
-        assertEquals("hello world", c.getRichStringCellValue().toString());
-        // Won't have preserve
-        assertEquals(
-                0,
-                c.getRichStringCellValue().getCTRst().xgetT().getDomNode().getAttributes().getLength()
-        );
-
-        // Apply a font
-        XSSFFont f = wb2.createFont();
-        f.setBold(true);
-        c.getRichStringCellValue().applyFont(0, 5, f);
-        assertEquals("hello world", c.getRichStringCellValue().toString());
-        // Does need preserving on the 2nd part
-        assertEquals(2, c.getRichStringCellValue().getCTRst().sizeOfRArray());
-        assertEquals(
-                0,
-                c.getRichStringCellValue().getCTRst().getRArray(0).xgetT().getDomNode().getAttributes().getLength()
-        );
-        assertEquals(
-                1,
-                c.getRichStringCellValue().getCTRst().getRArray(1).xgetT().getDomNode().getAttributes().getLength()
-        );
-        assertEquals(
-                "preserve",
-                c.getRichStringCellValue().getCTRst().getRArray(1).xgetT().getDomNode().getAttributes().item(0).getNodeValue()
-        );
-
-        // Save and check
-        XSSFWorkbook wb3 = XSSFTestDataSamples.writeOutAndReadBack(wb2);
-        wb2.close();
+            );
 
-        s = wb3.getSheetAt(0);
-        r = s.getRow(0);
-        c = r.getCell(0);
-        assertEquals("hello world", c.getRichStringCellValue().toString());
-        wb3.close();
+            // Save and check
+            try (XSSFWorkbook wb2 = writeOutAndReadBack(wb1)) {
+                s = wb2.getSheetAt(0);
+                r = s.getRow(0);
+                c = r.getCell(0);
+                assertEquals(" with spaces ", c.getRichStringCellValue().toString());
+                assertEquals(0, c.getRichStringCellValue().getCTRst().sizeOfRArray());
+                assertTrue(c.getRichStringCellValue().getCTRst().isSetT());
+
+                // Change the string
+                c.setCellValue(
+                    new XSSFRichTextString("hello world")
+                );
+                assertEquals("hello world", c.getRichStringCellValue().toString());
+                // Won't have preserve
+                assertEquals(
+                    0,
+                    c.getRichStringCellValue().getCTRst().xgetT().getDomNode().getAttributes().getLength()
+                );
+
+                // Apply a font
+                XSSFFont f = wb2.createFont();
+                f.setBold(true);
+                c.getRichStringCellValue().applyFont(0, 5, f);
+                assertEquals("hello world", c.getRichStringCellValue().toString());
+                // Does need preserving on the 2nd part
+                assertEquals(2, c.getRichStringCellValue().getCTRst().sizeOfRArray());
+                assertEquals(
+                    0,
+                    c.getRichStringCellValue().getCTRst().getRArray(0).xgetT().getDomNode().getAttributes().getLength()
+                );
+                assertEquals(
+                    1,
+                    c.getRichStringCellValue().getCTRst().getRArray(1).xgetT().getDomNode().getAttributes().getLength()
+                );
+                assertEquals(
+                    "preserve",
+                    c.getRichStringCellValue().getCTRst().getRArray(1).xgetT().getDomNode().getAttributes().item(0).getNodeValue()
+                );
+
+                // Save and check
+                try (XSSFWorkbook wb3 = writeOutAndReadBack(wb2)) {
+                    s = wb3.getSheetAt(0);
+                    r = s.getRow(0);
+                    c = r.getCell(0);
+                    assertEquals("hello world", c.getRichStringCellValue().toString());
+                }
+            }
+        }
     }
 
     /**
@@ -555,25 +551,15 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
      */
     @Test
     void bug49940() throws IOException {
-        try (XSSFWorkbook wb = XSSFTestDataSamples.openSampleWorkbook("styles.xlsx")) {
+        try (XSSFWorkbook wb = openSampleWorkbook("styles.xlsx")) {
             assertEquals(3, wb.getNumberOfSheets());
             assertEquals(10, wb.getStylesSource().getNumCellStyles());
 
-            ByteArrayOutputStream b1 = new ByteArrayOutputStream();
-            ByteArrayOutputStream b2 = new ByteArrayOutputStream();
-            ByteArrayOutputStream b3 = new ByteArrayOutputStream();
-            wb.write(b1);
-            wb.write(b2);
-            wb.write(b3);
-
-            for (byte[] data : new byte[][]{
-                    b1.toByteArray(), b2.toByteArray(), b3.toByteArray()
-            }) {
-                ByteArrayInputStream bais = new ByteArrayInputStream(data);
-                XSSFWorkbook wb2 = new XSSFWorkbook(bais);
-                assertEquals(3, wb2.getNumberOfSheets());
-                assertEquals(10, wb2.getStylesSource().getNumCellStyles());
-                wb2.close();
+            for (int i=0; i<3; i++) {
+                try (XSSFWorkbook wb2 = writeOutAndReadBack(wb)) {
+                    assertEquals(3, wb2.getNumberOfSheets());
+                    assertEquals(10, wb2.getStylesSource().getNumCellStyles());
+                }
             }
         }
     }
@@ -584,11 +570,10 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
      */
     @Test
     void bug49966() throws IOException {
-        try (XSSFWorkbook wb1 = XSSFTestDataSamples
-                .openSampleWorkbook("shared_formulas.xlsx")) {
+        try (XSSFWorkbook wb1 = openSampleWorkbook("shared_formulas.xlsx")) {
             XSSFSheet sheet = wb1.getSheetAt(0);
 
-            XSSFTestDataSamples.writeOutAndReadBack(wb1).close();
+            writeOutAndReadBack(wb1).close();
 
             // CalcChain has lots of entries
             CalculationChain cc = wb1.getCalculationChain();
@@ -601,7 +586,7 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
             assertEquals("A8", cc.getCTCalcChain().getCArray(6).getR());
             assertEquals(40, cc.getCTCalcChain().sizeOfCArray());
 
-            XSSFTestDataSamples.writeOutAndReadBack(wb1).close();
+            writeOutAndReadBack(wb1).close();
 
             // Try various ways of changing the formulas
             // If it stays a formula, chain entry should remain
@@ -609,25 +594,25 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
             sheet.getRow(1).getCell(0).setCellFormula("A1"); // stay
             sheet.getRow(2).getCell(0).setCellFormula(null); // go
             sheet.getRow(3).getCell(0).setCellFormula("14"); // stay
-            XSSFTestDataSamples.writeOutAndReadBack(wb1).close();
+            writeOutAndReadBack(wb1).close();
 
             sheet.getRow(4).getCell(0).setBlank(); // go
-            XSSFTestDataSamples.writeOutAndReadBack(wb1).close();
+            writeOutAndReadBack(wb1).close();
 
             validateCells(sheet);
             sheet.getRow(5).removeCell(sheet.getRow(5).getCell(0)); // go
             validateCells(sheet);
-            XSSFTestDataSamples.writeOutAndReadBack(wb1).close();
+            writeOutAndReadBack(wb1).close();
 
             sheet.getRow(6).getCell(0).setBlank(); // go
-            XSSFTestDataSamples.writeOutAndReadBack(wb1).close();
+            writeOutAndReadBack(wb1).close();
 
             sheet.getRow(7).getCell(0).setCellValue((String) null); // go
 
-            XSSFTestDataSamples.writeOutAndReadBack(wb1).close();
+            writeOutAndReadBack(wb1).close();
 
             // Save and check
-            try (XSSFWorkbook wb2 = XSSFTestDataSamples.writeOutAndReadBack(wb1)) {
+            try (XSSFWorkbook wb2 = writeOutAndReadBack(wb1)) {
                 wb1.close();
                 assertEquals(35, cc.getCTCalcChain().sizeOfCArray());
 
@@ -641,8 +626,7 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
 
     @Test
     void bug49966Row() throws IOException {
-        try (XSSFWorkbook wb = XSSFTestDataSamples
-                .openSampleWorkbook("shared_formulas.xlsx")) {
+        try (XSSFWorkbook wb = openSampleWorkbook("shared_formulas.xlsx")) {
             XSSFSheet sheet = wb.getSheetAt(0);
 
             validateCells(sheet);
@@ -660,7 +644,7 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
 
     @Test
     void bug49156() throws IOException {
-        try (Workbook wb = XSSFTestDataSamples.openSampleWorkbook("49156.xlsx")) {
+        try (Workbook wb = openSampleWorkbook("49156.xlsx")) {
             FormulaEvaluator formulaEvaluator = wb.getCreationHelper().createFormulaEvaluator();
 
             Sheet sheet = wb.getSheetAt(0);
@@ -680,7 +664,7 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
      */
     @Test
     void bug50440And51875() throws IOException {
-        try (Workbook wb = XSSFTestDataSamples.openSampleWorkbook("NewlineInFormulas.xlsx")) {
+        try (Workbook wb = openSampleWorkbook("NewlineInFormulas.xlsx")) {
             Sheet s = wb.getSheetAt(0);
             Cell c = s.getRow(0).getCell(0);
 
@@ -706,58 +690,55 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
      */
     @Test
     void bug50795() throws IOException {
-        XSSFWorkbook wb1 = XSSFTestDataSamples.openSampleWorkbook("50795.xlsx");
-        XSSFSheet sheet = wb1.getSheetAt(0);
-        XSSFRow row = sheet.getRow(0);
-
-        XSSFCell cellWith = row.getCell(0);
-        XSSFCell cellWithoutComment = row.getCell(1);
-
-        assertNotNull(cellWith.getCellComment());
-        assertNull(cellWithoutComment.getCellComment());
-
-        String exp = "\u0410\u0432\u0442\u043e\u0440:\ncomment";
-        XSSFComment comment = cellWith.getCellComment();
-        assertEquals(exp, comment.getString().getString());
+        try (XSSFWorkbook wb1 = openSampleWorkbook("50795.xlsx")) {
+            XSSFSheet sheet = wb1.getSheetAt(0);
+            XSSFRow row = sheet.getRow(0);
 
+            XSSFCell cellWith = row.getCell(0);
+            XSSFCell cellWithoutComment = row.getCell(1);
 
-        // Check we can write it out and read it back as-is
-        XSSFWorkbook wb2 = XSSFTestDataSamples.writeOutAndReadBack(wb1);
-        wb1.close();
+            assertNotNull(cellWith.getCellComment());
+            assertNull(cellWithoutComment.getCellComment());
 
-        sheet = wb2.getSheetAt(0);
-        row = sheet.getRow(0);
-        cellWith = row.getCell(0);
-        cellWithoutComment = row.getCell(1);
+            String exp = "\u0410\u0432\u0442\u043e\u0440:\ncomment";
+            XSSFComment comment = cellWith.getCellComment();
+            assertEquals(exp, comment.getString().getString());
 
-        // Double check things are as expected
-        assertNotNull(cellWith.getCellComment());
-        assertNull(cellWithoutComment.getCellComment());
-        comment = cellWith.getCellComment();
-        assertEquals(exp, comment.getString().getString());
 
+            // Check we can write it out and read it back as-is
+            try (XSSFWorkbook wb2 = writeOutAndReadBack(wb1)) {
+                sheet = wb2.getSheetAt(0);
+                row = sheet.getRow(0);
+                cellWith = row.getCell(0);
+                cellWithoutComment = row.getCell(1);
 
-        // Move the comment
-        cellWithoutComment.setCellComment(comment);
+                // Double check things are as expected
+                assertNotNull(cellWith.getCellComment());
+                assertNull(cellWithoutComment.getCellComment());
+                comment = cellWith.getCellComment();
+                assertEquals(exp, comment.getString().getString());
 
 
-        // Write out and re-check
-        XSSFWorkbook wb3 = XSSFTestDataSamples.writeOutAndReadBack(wb2);
-        wb2.close();
+                // Move the comment
+                cellWithoutComment.setCellComment(comment);
 
-        sheet = wb3.getSheetAt(0);
-        row = sheet.getRow(0);
 
-        // Ensure it swapped over
-        cellWith = row.getCell(0);
-        cellWithoutComment = row.getCell(1);
-        assertNull(cellWith.getCellComment());
-        assertNotNull(cellWithoutComment.getCellComment());
+                // Write out and re-check
+                try (XSSFWorkbook wb3 = writeOutAndReadBack(wb2)) {
+                    sheet = wb3.getSheetAt(0);
+                    row = sheet.getRow(0);
 
-        comment = cellWithoutComment.getCellComment();
-        assertEquals(exp, comment.getString().getString());
+                    // Ensure it swapped over
+                    cellWith = row.getCell(0);
+                    cellWithoutComment = row.getCell(1);
+                    assertNull(cellWith.getCellComment());
+                    assertNotNull(cellWithoutComment.getCellComment());
 
-        wb3.close();
+                    comment = cellWithoutComment.getCellComment();
+                    assertEquals(exp, comment.getString().getString());
+                }
+            }
+        }
     }
 
     /**
@@ -768,7 +749,7 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
      */
     @Test
     void bug50299() throws IOException {
-        try (Workbook wb = XSSFTestDataSamples.openSampleWorkbook("50299.xlsx")) {
+        try (Workbook wb = openSampleWorkbook("50299.xlsx")) {
 
             // Check all the colours
             for (int sn = 0; sn < wb.getNumberOfSheets(); sn++) {
@@ -799,7 +780,7 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
      */
     @Test
     void bug50786() throws IOException {
-        try (XSSFWorkbook wb = XSSFTestDataSamples.openSampleWorkbook("50786-indexed_colours.xlsx")) {
+        try (XSSFWorkbook wb = openSampleWorkbook("50786-indexed_colours.xlsx")) {
             XSSFSheet s = wb.getSheetAt(0);
             XSSFRow r = s.getRow(2);
 
@@ -822,7 +803,7 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
      */
     @Test
     void bug50846() throws IOException {
-        try (XSSFWorkbook wb = XSSFTestDataSamples.openSampleWorkbook("50846-border_colours.xlsx")) {
+        try (XSSFWorkbook wb = openSampleWorkbook("50846-border_colours.xlsx")) {
 
             XSSFSheet sheet = wb.getSheetAt(0);
             XSSFRow row = sheet.getRow(0);
@@ -852,7 +833,7 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
      */
     @Test
     void bug50784() throws IOException {
-        try (XSSFWorkbook wb = XSSFTestDataSamples.openSampleWorkbook("50784-font_theme_colours.xlsx")) {
+        try (XSSFWorkbook wb = openSampleWorkbook("50784-font_theme_colours.xlsx")) {
             XSSFSheet s = wb.getSheetAt(0);
             XSSFRow r = s.getRow(0);
 
@@ -886,69 +867,65 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
         String text = "Use \n with word wrap on to create a new line.\n" +
                 "This line finishes with two trailing spaces.  ";
 
-        XSSFWorkbook wb1 = new XSSFWorkbook();
-        XSSFSheet sheet = wb1.createSheet();
+        try (XSSFWorkbook wb1 = new XSSFWorkbook()) {
+            XSSFSheet sheet = wb1.createSheet();
 
-        Font font1 = wb1.createFont();
-        font1.setColor((short) 20);
-        Font font2 = wb1.createFont();
-        font2.setColor(Font.COLOR_RED);
-        Font font3 = wb1.getFontAt(0);
+            Font font1 = wb1.createFont();
+            font1.setColor((short) 20);
+            Font font2 = wb1.createFont();
+            font2.setColor(Font.COLOR_RED);
+            Font font3 = wb1.getFontAt(0);
 
-        XSSFRow row = sheet.createRow(2);
-        XSSFCell cell = row.createCell(2);
+            XSSFRow row = sheet.createRow(2);
+            XSSFCell cell = row.createCell(2);
 
-        XSSFRichTextString richTextString =
+            XSSFRichTextString richTextString =
                 wb1.getCreationHelper().createRichTextString(text);
 
-        // Check the text has the newline
-        assertEquals(text, richTextString.getString());
-
-        // Apply the font
-        richTextString.applyFont(font3);
-        richTextString.applyFont(0, 3, font1);
-        cell.setCellValue(richTextString);
+            // Check the text has the newline
+            assertEquals(text, richTextString.getString());
 
-        // To enable newlines you need set a cell styles with wrap=true
-        CellStyle cs = wb1.createCellStyle();
-        cs.setWrapText(true);
-        cell.setCellStyle(cs);
+            // Apply the font
+            richTextString.applyFont(font3);
+            richTextString.applyFont(0, 3, font1);
+            cell.setCellValue(richTextString);
 
-        // Check the text has the
-        assertEquals(text, cell.getStringCellValue());
+            // To enable newlines you need set a cell styles with wrap=true
+            CellStyle cs = wb1.createCellStyle();
+            cs.setWrapText(true);
+            cell.setCellStyle(cs);
 
-        // Save the file and re-read it
-        XSSFWorkbook wb2 = XSSFTestDataSamples.writeOutAndReadBack(wb1);
-        wb1.close();
-        sheet = wb2.getSheetAt(0);
-        row = sheet.getRow(2);
-        cell = row.getCell(2);
-        assertEquals(text, cell.getStringCellValue());
+            // Check the text has the
+            assertEquals(text, cell.getStringCellValue());
 
-        // Now add a 2nd, and check again
-        int fontAt = text.indexOf('\n', 6);
-        cell.getRichStringCellValue().applyFont(10, fontAt + 1, font2);
-        assertEquals(text, cell.getStringCellValue());
+            // Save the file and re-read it
+            try (XSSFWorkbook wb2 = writeOutAndReadBack(wb1)) {
+                sheet = wb2.getSheetAt(0);
+                row = sheet.getRow(2);
+                cell = row.getCell(2);
+                assertEquals(text, cell.getStringCellValue());
 
-        assertEquals(4, cell.getRichStringCellValue().numFormattingRuns());
-        assertEquals("Use", cell.getRichStringCellValue().getCTRst().getRArray(0).getT());
+                // Now add a 2nd, and check again
+                int fontAt = text.indexOf('\n', 6);
+                cell.getRichStringCellValue().applyFont(10, fontAt + 1, font2);
+                assertEquals(text, cell.getStringCellValue());
 
-        String r3 = cell.getRichStringCellValue().getCTRst().getRArray(2).getT();
-        assertEquals("line.\n", r3.substring(r3.length() - 6));
+                assertEquals(4, cell.getRichStringCellValue().numFormattingRuns());
+                assertEquals("Use", cell.getRichStringCellValue().getCTRst().getRArray(0).getT());
 
-        // Save and re-check
-        XSSFWorkbook wb3 = XSSFTestDataSamples.writeOutAndReadBack(wb2);
-        wb2.close();
+                String r3 = cell.getRichStringCellValue().getCTRst().getRArray(2).getT();
+                assertEquals("line.\n", r3.substring(r3.length() - 6));
 
-        sheet = wb3.getSheetAt(0);
-        row = sheet.getRow(2);
-        cell = row.getCell(2);
-        assertEquals(text, cell.getStringCellValue());
-        wb3.close();
+                // Save and re-check
+                try (XSSFWorkbook wb3 = writeOutAndReadBack(wb2)) {
 
-        // FileOutputStream out = new FileOutputStream("/tmp/test48877.xlsx");
-        // wb.write(out);
-        // out.close();
+                    sheet = wb3.getSheetAt(0);
+                    row = sheet.getRow(2);
+                    cell = row.getCell(2);
+                    assertEquals(text, cell.getStringCellValue());
+                }
+            }
+        }
     }
 
     /**
@@ -956,119 +933,118 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
      */
     @Test
     void bug50867() throws IOException {
-        XSSFWorkbook wb1 = XSSFTestDataSamples.openSampleWorkbook("50867_with_table.xlsx");
-        assertEquals(3, wb1.getNumberOfSheets());
-
-        XSSFSheet s1 = wb1.getSheetAt(0);
-        XSSFSheet s2 = wb1.getSheetAt(1);
-        XSSFSheet s3 = wb1.getSheetAt(2);
-        assertEquals(1, s1.getTables().size());
-        assertEquals(0, s2.getTables().size());
-        assertEquals(0, s3.getTables().size());
-
-        XSSFTable t = s1.getTables().get(0);
-        assertEquals("Tabella1", t.getName());
-        assertEquals("Tabella1", t.getDisplayName());
-        assertEquals("A1:C3", t.getCTTable().getRef());
-
-        // Add a sheet and re-order
-        XSSFSheet s4 = wb1.createSheet("NewSheet");
-        wb1.setSheetOrder(s4.getSheetName(), 0);
-
-        // Check on tables
-        assertEquals(1, s1.getTables().size());
-        assertEquals(0, s2.getTables().size());
-        assertEquals(0, s3.getTables().size());
-        assertEquals(0, s4.getTables().size());
-
-        // Refetch to get the new order
-        s1 = wb1.getSheetAt(0);
-        s2 = wb1.getSheetAt(1);
-        s3 = wb1.getSheetAt(2);
-        s4 = wb1.getSheetAt(3);
-        assertEquals(0, s1.getTables().size());
-        assertEquals(1, s2.getTables().size());
-        assertEquals(0, s3.getTables().size());
-        assertEquals(0, s4.getTables().size());
-
-        // Save and re-load
-        XSSFWorkbook wb2 = XSSFTestDataSamples.writeOutAndReadBack(wb1);
-        wb1.close();
-
-        s1 = wb2.getSheetAt(0);
-        s2 = wb2.getSheetAt(1);
-        s3 = wb2.getSheetAt(2);
-        s4 = wb2.getSheetAt(3);
-        assertEquals(0, s1.getTables().size());
-        assertEquals(1, s2.getTables().size());
-        assertEquals(0, s3.getTables().size());
-        assertEquals(0, s4.getTables().size());
-
-        t = s2.getTables().get(0);
-        assertEquals("Tabella1", t.getName());
-        assertEquals("Tabella1", t.getDisplayName());
-        assertEquals("A1:C3", t.getCTTable().getRef());
-
-
-        // Add some more tables, and check
-        t = s2.createTable(null);
-        t.setName("New 2");
-        t.setDisplayName("New 2");
-        t = s3.createTable(null);
-        t.setName("New 3");
-        t.setDisplayName("New 3");
-
-        XSSFWorkbook wb3 = XSSFTestDataSamples.writeOutAndReadBack(wb2);
-        wb2.close();
-        s1 = wb3.getSheetAt(0);
-        s2 = wb3.getSheetAt(1);
-        s3 = wb3.getSheetAt(2);
-        s4 = wb3.getSheetAt(3);
-        assertEquals(0, s1.getTables().size());
-        assertEquals(2, s2.getTables().size());
-        assertEquals(1, s3.getTables().size());
-        assertEquals(0, s4.getTables().size());
-
-        t = s2.getTables().get(0);
-        assertEquals("Tabella1", t.getName());
-        assertEquals("Tabella1", t.getDisplayName());
-        assertEquals("A1:C3", t.getCTTable().getRef());
-
-        t = s2.getTables().get(1);
-        assertEquals("New 2", t.getName());
-        assertEquals("New 2", t.getDisplayName());
-
-        t = s3.getTables().get(0);
-        assertEquals("New 3", t.getName());
-        assertEquals("New 3", t.getDisplayName());
-
-        // Check the relationships
-        assertEquals(0, s1.getRelations().size());
-        assertEquals(3, s2.getRelations().size());
-        assertEquals(1, s3.getRelations().size());
-        assertEquals(0, s4.getRelations().size());
-
-        assertEquals(
-                XSSFRelation.PRINTER_SETTINGS.getContentType(),
-                s2.getRelations().get(0).getPackagePart().getContentType()
-        );
-        assertEquals(
-                XSSFRelation.TABLE.getContentType(),
-                s2.getRelations().get(1).getPackagePart().getContentType()
-        );
-        assertEquals(
-                XSSFRelation.TABLE.getContentType(),
-                s2.getRelations().get(2).getPackagePart().getContentType()
-        );
-        assertEquals(
-                XSSFRelation.TABLE.getContentType(),
-                s3.getRelations().get(0).getPackagePart().getContentType()
-        );
-        assertEquals(
-                "/xl/tables/table3.xml",
-                s3.getRelations().get(0).getPackagePart().getPartName().toString()
-        );
-        wb3.close();
+        try (XSSFWorkbook wb1 = openSampleWorkbook("50867_with_table.xlsx")) {
+            assertEquals(3, wb1.getNumberOfSheets());
+
+            XSSFSheet s1 = wb1.getSheetAt(0);
+            XSSFSheet s2 = wb1.getSheetAt(1);
+            XSSFSheet s3 = wb1.getSheetAt(2);
+            assertEquals(1, s1.getTables().size());
+            assertEquals(0, s2.getTables().size());
+            assertEquals(0, s3.getTables().size());
+
+            XSSFTable t = s1.getTables().get(0);
+            assertEquals("Tabella1", t.getName());
+            assertEquals("Tabella1", t.getDisplayName());
+            assertEquals("A1:C3", t.getCTTable().getRef());
+
+            // Add a sheet and re-order
+            XSSFSheet s4 = wb1.createSheet("NewSheet");
+            wb1.setSheetOrder(s4.getSheetName(), 0);
+
+            // Check on tables
+            assertEquals(1, s1.getTables().size());
+            assertEquals(0, s2.getTables().size());
+            assertEquals(0, s3.getTables().size());
+            assertEquals(0, s4.getTables().size());
+
+            // Refetch to get the new order
+            s1 = wb1.getSheetAt(0);
+            s2 = wb1.getSheetAt(1);
+            s3 = wb1.getSheetAt(2);
+            s4 = wb1.getSheetAt(3);
+            assertEquals(0, s1.getTables().size());
+            assertEquals(1, s2.getTables().size());
+            assertEquals(0, s3.getTables().size());
+            assertEquals(0, s4.getTables().size());
+
+            // Save and re-load
+            try (XSSFWorkbook wb2 = writeOutAndReadBack(wb1)) {
+                s1 = wb2.getSheetAt(0);
+                s2 = wb2.getSheetAt(1);
+                s3 = wb2.getSheetAt(2);
+                s4 = wb2.getSheetAt(3);
+                assertEquals(0, s1.getTables().size());
+                assertEquals(1, s2.getTables().size());
+                assertEquals(0, s3.getTables().size());
+                assertEquals(0, s4.getTables().size());
+
+                t = s2.getTables().get(0);
+                assertEquals("Tabella1", t.getName());
+                assertEquals("Tabella1", t.getDisplayName());
+                assertEquals("A1:C3", t.getCTTable().getRef());
+
+
+                // Add some more tables, and check
+                t = s2.createTable(null);
+                t.setName("New 2");
+                t.setDisplayName("New 2");
+                t = s3.createTable(null);
+                t.setName("New 3");
+                t.setDisplayName("New 3");
+
+                try (XSSFWorkbook wb3 = writeOutAndReadBack(wb2)) {
+                    s1 = wb3.getSheetAt(0);
+                    s2 = wb3.getSheetAt(1);
+                    s3 = wb3.getSheetAt(2);
+                    s4 = wb3.getSheetAt(3);
+                    assertEquals(0, s1.getTables().size());
+                    assertEquals(2, s2.getTables().size());
+                    assertEquals(1, s3.getTables().size());
+                    assertEquals(0, s4.getTables().size());
+
+                    t = s2.getTables().get(0);
+                    assertEquals("Tabella1", t.getName());
+                    assertEquals("Tabella1", t.getDisplayName());
+                    assertEquals("A1:C3", t.getCTTable().getRef());
+
+                    t = s2.getTables().get(1);
+                    assertEquals("New 2", t.getName());
+                    assertEquals("New 2", t.getDisplayName());
+
+                    t = s3.getTables().get(0);
+                    assertEquals("New 3", t.getName());
+                    assertEquals("New 3", t.getDisplayName());
+
+                    // Check the relationships
+                    assertEquals(0, s1.getRelations().size());
+                    assertEquals(3, s2.getRelations().size());
+                    assertEquals(1, s3.getRelations().size());
+                    assertEquals(0, s4.getRelations().size());
+
+                    assertEquals(
+                        XSSFRelation.PRINTER_SETTINGS.getContentType(),
+                        s2.getRelations().get(0).getPackagePart().getContentType()
+                    );
+                    assertEquals(
+                        XSSFRelation.TABLE.getContentType(),
+                        s2.getRelations().get(1).getPackagePart().getContentType()
+                    );
+                    assertEquals(
+                        XSSFRelation.TABLE.getContentType(),
+                        s2.getRelations().get(2).getPackagePart().getContentType()
+                    );
+                    assertEquals(
+                        XSSFRelation.TABLE.getContentType(),
+                        s3.getRelations().get(0).getPackagePart().getContentType()
+                    );
+                    assertEquals(
+                        "/xl/tables/table3.xml",
+                        s3.getRelations().get(0).getPackagePart().getPartName().toString()
+                    );
+                }
+            }
+        }
     }
 
     /**
@@ -1077,45 +1053,43 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
      */
     @Test
     void bug49253() throws IOException {
-        XSSFWorkbook wb1 = new XSSFWorkbook();
-        XSSFWorkbook wb2 = new XSSFWorkbook();
-        CellRangeAddress cra = CellRangeAddress.valueOf("C2:D3");
-
-        // No print settings before repeating
-        XSSFSheet s1 = wb1.createSheet();
-        assertFalse(s1.getCTWorksheet().isSetPageSetup());
-        assertTrue(s1.getCTWorksheet().isSetPageMargins());
-        s1.setRepeatingColumns(cra);
-        s1.setRepeatingRows(cra);
+        try (XSSFWorkbook wb1 = new XSSFWorkbook();
+             XSSFWorkbook wb2 = new XSSFWorkbook()) {
+            CellRangeAddress cra = CellRangeAddress.valueOf("C2:D3");
 
-        assertTrue(s1.getCTWorksheet().isSetPageSetup());
-        assertTrue(s1.getCTWorksheet().isSetPageMargins());
+            // No print settings before repeating
+            XSSFSheet s1 = wb1.createSheet();
+            assertFalse(s1.getCTWorksheet().isSetPageSetup());
+            assertTrue(s1.getCTWorksheet().isSetPageMargins());
+            s1.setRepeatingColumns(cra);
+            s1.setRepeatingRows(cra);
 
-        PrintSetup ps1 = s1.getPrintSetup();
-        assertFalse(ps1.getValidSettings());
-        assertFalse(ps1.getLandscape());
+            assertTrue(s1.getCTWorksheet().isSetPageSetup());
+            assertTrue(s1.getCTWorksheet().isSetPageMargins());
 
+            PrintSetup ps1 = s1.getPrintSetup();
+            assertFalse(ps1.getValidSettings());
+            assertFalse(ps1.getLandscape());
 
-        // Had valid print settings before repeating
-        XSSFSheet s2 = wb2.createSheet();
-        PrintSetup ps2 = s2.getPrintSetup();
-        assertTrue(s2.getCTWorksheet().isSetPageSetup());
-        assertTrue(s2.getCTWorksheet().isSetPageMargins());
 
-        ps2.setLandscape(false);
-        assertTrue(ps2.getValidSettings());
-        assertFalse(ps2.getLandscape());
-        s2.setRepeatingColumns(cra);
-        s2.setRepeatingRows(cra);
+            // Had valid print settings before repeating
+            XSSFSheet s2 = wb2.createSheet();
+            PrintSetup ps2 = s2.getPrintSetup();
+            assertTrue(s2.getCTWorksheet().isSetPageSetup());
+            assertTrue(s2.getCTWorksheet().isSetPageMargins());
 
-        ps2 = s2.getPrintSetup();
-        assertTrue(s2.getCTWorksheet().isSetPageSetup());
-        assertTrue(s2.getCTWorksheet().isSetPageMargins());
-        assertTrue(ps2.getValidSettings());
-        assertFalse(ps2.getLandscape());
+            ps2.setLandscape(false);
+            assertTrue(ps2.getValidSettings());
+            assertFalse(ps2.getLandscape());
+            s2.setRepeatingColumns(cra);
+            s2.setRepeatingRows(cra);
 
-        wb1.close();
-        wb2.close();
+            ps2 = s2.getPrintSetup();
+            assertTrue(s2.getCTWorksheet().isSetPageSetup());
+            assertTrue(s2.getCTWorksheet().isSetPageMargins());
+            assertTrue(ps2.getValidSettings());
+            assertFalse(ps2.getLandscape());
+        }
     }
 
     /**
@@ -1123,77 +1097,77 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
      */
     @Test
     void bug51037() throws IOException {
-        XSSFWorkbook wb = new XSSFWorkbook();
-        XSSFSheet s = wb.createSheet();
-
-        CellStyle defaultStyle = wb.getCellStyleAt((short) 0);
-        assertEquals(0, defaultStyle.getIndex());
-
-        CellStyle blueStyle = wb.createCellStyle();
-        blueStyle.setFillForegroundColor(IndexedColors.AQUA.getIndex());
-        blueStyle.setFillPattern(FillPatternType.SOLID_FOREGROUND);
-        assertEquals(1, blueStyle.getIndex());
-
-        CellStyle pinkStyle = wb.createCellStyle();
-        pinkStyle.setFillForegroundColor(IndexedColors.PINK.getIndex());
-        pinkStyle.setFillPattern(FillPatternType.SOLID_FOREGROUND);
-        assertEquals(2, pinkStyle.getIndex());
-
-        // Starts empty
-        assertEquals(1, s.getCTWorksheet().sizeOfColsArray());
-        CTCols cols = s.getCTWorksheet().getColsArray(0);
-        assertEquals(0, cols.sizeOfColArray());
-
-        // Add some rows and columns
-        XSSFRow r1 = s.createRow(0);
-        XSSFRow r2 = s.createRow(1);
-        r1.createCell(0);
-        r1.createCell(2);
-        r2.createCell(0);
-        r2.createCell(3);
-
-        // Check no style is there
-        assertEquals(1, s.getCTWorksheet().sizeOfColsArray());
-        assertEquals(0, cols.sizeOfColArray());
-
-        assertEquals(defaultStyle, s.getColumnStyle(0));
-        assertEquals(defaultStyle, s.getColumnStyle(2));
-        assertEquals(defaultStyle, s.getColumnStyle(3));
-
-
-        // Apply the styles
-        s.setDefaultColumnStyle(0, pinkStyle);
-        s.setDefaultColumnStyle(3, blueStyle);
-
-        // Check
-        assertEquals(pinkStyle, s.getColumnStyle(0));
-        assertEquals(defaultStyle, s.getColumnStyle(2));
-        assertEquals(blueStyle, s.getColumnStyle(3));
-
-        assertEquals(1, s.getCTWorksheet().sizeOfColsArray());
-        assertEquals(2, cols.sizeOfColArray());
-
-        assertEquals(1, cols.getColArray(0).getMin());
-        assertEquals(1, cols.getColArray(0).getMax());
-        assertEquals(pinkStyle.getIndex(), cols.getColArray(0).getStyle());
-
-        assertEquals(4, cols.getColArray(1).getMin());
-        assertEquals(4, cols.getColArray(1).getMax());
-        assertEquals(blueStyle.getIndex(), cols.getColArray(1).getStyle());
-
-
-        // Save, re-load and re-check
-        XSSFWorkbook wbBack = XSSFTestDataSamples.writeOutAndReadBack(wb);
-        wb.close();
-        s = wbBack.getSheetAt(0);
-        defaultStyle = wbBack.getCellStyleAt(defaultStyle.getIndex());
-        blueStyle = wbBack.getCellStyleAt(blueStyle.getIndex());
-        pinkStyle = wbBack.getCellStyleAt(pinkStyle.getIndex());
-
-        assertEquals(pinkStyle, s.getColumnStyle(0));
-        assertEquals(defaultStyle, s.getColumnStyle(2));
-        assertEquals(blueStyle, s.getColumnStyle(3));
-        wbBack.close();
+        try (XSSFWorkbook wb = new XSSFWorkbook()) {
+            XSSFSheet s = wb.createSheet();
+
+            CellStyle defaultStyle = wb.getCellStyleAt((short) 0);
+            assertEquals(0, defaultStyle.getIndex());
+
+            CellStyle blueStyle = wb.createCellStyle();
+            blueStyle.setFillForegroundColor(IndexedColors.AQUA.getIndex());
+            blueStyle.setFillPattern(FillPatternType.SOLID_FOREGROUND);
+            assertEquals(1, blueStyle.getIndex());
+
+            CellStyle pinkStyle = wb.createCellStyle();
+            pinkStyle.setFillForegroundColor(IndexedColors.PINK.getIndex());
+            pinkStyle.setFillPattern(FillPatternType.SOLID_FOREGROUND);
+            assertEquals(2, pinkStyle.getIndex());
+
+            // Starts empty
+            assertEquals(1, s.getCTWorksheet().sizeOfColsArray());
+            CTCols cols = s.getCTWorksheet().getColsArray(0);
+            assertEquals(0, cols.sizeOfColArray());
+
+            // Add some rows and columns
+            XSSFRow r1 = s.createRow(0);
+            XSSFRow r2 = s.createRow(1);
+            r1.createCell(0);
+            r1.createCell(2);
+            r2.createCell(0);
+            r2.createCell(3);
+
+            // Check no style is there
+            assertEquals(1, s.getCTWorksheet().sizeOfColsArray());
+            assertEquals(0, cols.sizeOfColArray());
+
+            assertEquals(defaultStyle, s.getColumnStyle(0));
+            assertEquals(defaultStyle, s.getColumnStyle(2));
+            assertEquals(defaultStyle, s.getColumnStyle(3));
+
+
+            // Apply the styles
+            s.setDefaultColumnStyle(0, pinkStyle);
+            s.setDefaultColumnStyle(3, blueStyle);
+
+            // Check
+            assertEquals(pinkStyle, s.getColumnStyle(0));
+            assertEquals(defaultStyle, s.getColumnStyle(2));
+            assertEquals(blueStyle, s.getColumnStyle(3));
+
+            assertEquals(1, s.getCTWorksheet().sizeOfColsArray());
+            assertEquals(2, cols.sizeOfColArray());
+
+            assertEquals(1, cols.getColArray(0).getMin());
+            assertEquals(1, cols.getColArray(0).getMax());
+            assertEquals(pinkStyle.getIndex(), cols.getColArray(0).getStyle());
+
+            assertEquals(4, cols.getColArray(1).getMin());
+            assertEquals(4, cols.getColArray(1).getMax());
+            assertEquals(blueStyle.getIndex(), cols.getColArray(1).getStyle());
+
+
+            // Save, re-load and re-check
+            try (XSSFWorkbook wbBack = writeOutAndReadBack(wb)) {
+                s = wbBack.getSheetAt(0);
+                defaultStyle = wbBack.getCellStyleAt(defaultStyle.getIndex());
+                blueStyle = wbBack.getCellStyleAt(blueStyle.getIndex());
+                pinkStyle = wbBack.getCellStyleAt(pinkStyle.getIndex());
+
+                assertEquals(pinkStyle, s.getColumnStyle(0));
+                assertEquals(defaultStyle, s.getColumnStyle(2));
+                assertEquals(blueStyle, s.getColumnStyle(3));
+            }
+        }
     }
 
     /**
@@ -1203,9 +1177,9 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
     @Test
     void bug46662() throws IOException {
         for (int i=0; i<2; i++) {
-            try (XSSFWorkbook wb1 = (i == 0) ? new XSSFWorkbook() : XSSFTestDataSamples.openSampleWorkbook("sample.xlsx")) {
+            try (XSSFWorkbook wb1 = (i == 0) ? new XSSFWorkbook() : openSampleWorkbook("sample.xlsx")) {
                 for (int j=0; j<3; j++) {
-                    try (XSSFWorkbook wb2 = XSSFTestDataSamples.writeOutAndReadBack(wb1)) {
+                    try (XSSFWorkbook wb2 = writeOutAndReadBack(wb1)) {
                         assertEquals(wb1.getNumberOfSheets(), wb2.getNumberOfSheets());
                     }
                 }
@@ -1220,7 +1194,7 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
      */
     @Test
     void bug51222() throws IOException {
-        try (XSSFWorkbook wb = XSSFTestDataSamples.openSampleWorkbook("51222.xlsx")) {
+        try (XSSFWorkbook wb = openSampleWorkbook("51222.xlsx")) {
             XSSFSheet s = wb.getSheetAt(0);
 
             XSSFCell cA4_EEECE1 = s.getRow(3).getCell(0);
@@ -1260,7 +1234,7 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
 
     @Test
     void bug51470() throws IOException {
-        try (XSSFWorkbook wb = XSSFTestDataSamples.openSampleWorkbook("51470.xlsx")) {
+        try (XSSFWorkbook wb = openSampleWorkbook("51470.xlsx")) {
             XSSFSheet sh0 = wb.getSheetAt(0);
             XSSFSheet sh1 = wb.cloneSheet(0);
             List<RelationPart> rels0 = sh0.getRelationParts();
@@ -1286,64 +1260,64 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
      */
     @Test
     void bug51850() throws IOException {
-        XSSFWorkbook wb1 = XSSFTestDataSamples.openSampleWorkbook("51850.xlsx");
-        XSSFSheet sh1 = wb1.getSheetAt(0);
-        XSSFSheet sh2 = wb1.getSheetAt(1);
+        try (XSSFWorkbook wb1 = openSampleWorkbook("51850.xlsx")) {
+            XSSFSheet sh1 = wb1.getSheetAt(0);
+            XSSFSheet sh2 = wb1.getSheetAt(1);
 
-        // Sheet 2 has comments
-        assertNotNull(sh2.getCommentsTable(false));
-        assertEquals(1, sh2.getCommentsTable(false).getNumberOfComments());
+            // Sheet 2 has comments
+            assertNotNull(sh2.getCommentsTable(false));
+            assertEquals(1, sh2.getCommentsTable(false).getNumberOfComments());
 
-        // Sheet 1 doesn't (yet)
-        assertNull(sh1.getCommentsTable(false));
+            // Sheet 1 doesn't (yet)
+            assertNull(sh1.getCommentsTable(false));
 
-        // Try to add comments to Sheet 1
-        CreationHelper factory = wb1.getCreationHelper();
-        Drawing<?> drawing = sh1.createDrawingPatriarch();
+            // Try to add comments to Sheet 1
+            CreationHelper factory = wb1.getCreationHelper();
+            Drawing<?> drawing = sh1.createDrawingPatriarch();
 
-        ClientAnchor anchor = factory.createClientAnchor();
-        anchor.setCol1(0);
-        anchor.setCol2(4);
-        anchor.setRow1(0);
-        anchor.setRow2(1);
+            ClientAnchor anchor = factory.createClientAnchor();
+            anchor.setCol1(0);
+            anchor.setCol2(4);
+            anchor.setRow1(0);
+            anchor.setRow2(1);
 
-        Comment comment1 = drawing.createCellComment(anchor);
-        comment1.setString(
+            Comment comment1 = drawing.createCellComment(anchor);
+            comment1.setString(
                 factory.createRichTextString("I like this cell. It's my favourite."));
-        comment1.setAuthor("Bob T. Fish");
-
-        anchor = factory.createClientAnchor();
-        anchor.setCol1(0);
-        anchor.setCol2(4);
-        anchor.setRow1(1);
-        anchor.setRow2(1);
-        Comment comment2 = drawing.createCellComment(anchor);
-        comment2.setString(
+            comment1.setAuthor("Bob T. Fish");
+
+            anchor = factory.createClientAnchor();
+            anchor.setCol1(0);
+            anchor.setCol2(4);
+            anchor.setRow1(1);
+            anchor.setRow2(1);
+            Comment comment2 = drawing.createCellComment(anchor);
+            comment2.setString(
                 factory.createRichTextString("This is much less fun..."));
-        comment2.setAuthor("Bob T. Fish");
+            comment2.setAuthor("Bob T. Fish");
 
-        Cell c1 = sh1.getRow(0).createCell(4);
-        c1.setCellValue(2.3);
-        c1.setCellComment(comment1);
+            Cell c1 = sh1.getRow(0).createCell(4);
+            c1.setCellValue(2.3);
+            c1.setCellComment(comment1);
 
-        Cell c2 = sh1.getRow(0).createCell(5);
-        c2.setCellValue(2.1);
-        c2.setCellComment(comment2);
+            Cell c2 = sh1.getRow(0).createCell(5);
+            c2.setCellValue(2.1);
+            c2.setCellComment(comment2);
 
 
-        // Save and re-load
-        XSSFWorkbook wb2 = XSSFTestDataSamples.writeOutAndReadBack(wb1);
-        wb1.close();
-        sh1 = wb2.getSheetAt(0);
-        sh2 = wb2.getSheetAt(1);
+            // Save and re-load
+            try (XSSFWorkbook wb2 = writeOutAndReadBack(wb1)) {
+                sh1 = wb2.getSheetAt(0);
+                sh2 = wb2.getSheetAt(1);
 
-        // Check the comments
-        assertNotNull(sh2.getCommentsTable(false));
-        assertEquals(1, sh2.getCommentsTable(false).getNumberOfComments());
+                // Check the comments
+                assertNotNull(sh2.getCommentsTable(false));
+                assertEquals(1, sh2.getCommentsTable(false).getNumberOfComments());
 
-        assertNotNull(sh1.getCommentsTable(false));
-        assertEquals(2, sh1.getCommentsTable(false).getNumberOfComments());
-        wb2.close();
+                assertNotNull(sh1.getCommentsTable(false));
+                assertEquals(2, sh1.getCommentsTable(false).getNumberOfComments());
+            }
+        }
     }
 
     /**
@@ -1351,7 +1325,7 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
      */
     @Test
     void bug51963() throws IOException {
-        try (XSSFWorkbook wb = XSSFTestDataSamples.openSampleWorkbook("51963.xlsx")) {
+        try (XSSFWorkbook wb = openSampleWorkbook("51963.xlsx")) {
             Sheet sheet = wb.getSheetAt(0);
             assertEquals("Abc,1", sheet.getSheetName());
 
@@ -1372,7 +1346,7 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
      */
     @Test
     void bug48703() throws IOException {
-        try (XSSFWorkbook wb = XSSFTestDataSamples.openSampleWorkbook("48703.xlsx")) {
+        try (XSSFWorkbook wb = openSampleWorkbook("48703.xlsx")) {
             XSSFSheet sheet = wb.getSheetAt(0);
 
             // Contains two forms, one with a range and one a list
@@ -1402,7 +1376,7 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
      */
     @Test
     void bug51710() throws IOException {
-        try (Workbook wb = XSSFTestDataSamples.openSampleWorkbook("51710.xlsx")) {
+        try (Workbook wb = openSampleWorkbook("51710.xlsx")) {
 
             final String[] columns = {"A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M", "N"};
             final int rowMax = 500; // bug triggers on row index 59
@@ -1434,7 +1408,7 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
      */
     @Test
     void bug5301() throws IOException {
-        try (Workbook wb = XSSFTestDataSamples.openSampleWorkbook("53101.xlsx")) {
+        try (Workbook wb = openSampleWorkbook("53101.xlsx")) {
             FormulaEvaluator evaluator =
                     wb.getCreationHelper().createFormulaEvaluator();
             // A1: SUM(B1: IZ1)
@@ -1455,7 +1429,7 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
 
     @Test
     void bug54436() throws IOException {
-        try (Workbook wb = XSSFTestDataSamples.openSampleWorkbook("54436.xlsx")) {
+        try (Workbook wb = openSampleWorkbook("54436.xlsx")) {
             if (!WorkbookEvaluator.getSupportedFunctionNames().contains("GETPIVOTDATA")) {
                 Function func = (args, srcRowIndex, srcColumnIndex) -> ErrorEval.NA;
 
@@ -1507,7 +1481,7 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
 
     @Test
     void bug53282() throws IOException {
-        try (Workbook wb = XSSFTestDataSamples.openSampleWorkbook("53282b.xlsx")) {
+        try (Workbook wb = openSampleWorkbook("53282b.xlsx")) {
             Cell c = wb.getSheetAt(0).getRow(1).getCell(0);
             assertEquals("#@_#", c.getStringCellValue());
             assertEquals("http://invalid.uri", c.getHyperlink().getAddress());
@@ -1521,11 +1495,11 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
      */
     @Test
     void bug56278() throws IOException {
-        try (Workbook wb = XSSFTestDataSamples.openSampleWorkbook("56278.xlsx")) {
+        try (Workbook wb = openSampleWorkbook("56278.xlsx")) {
             assertEquals(0, wb.getSheetIndex("Market Rates"));
 
             // Save and re-check
-            Workbook nwb = XSSFTestDataSamples.writeOutAndReadBack(wb);
+            Workbook nwb = writeOutAndReadBack(wb);
             assertEquals(0, nwb.getSheetIndex("Market Rates"));
             nwb.close();
         }
@@ -1533,7 +1507,7 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
 
     @Test
     void bug56315() throws IOException {
-        try (XSSFWorkbook wb = XSSFTestDataSamples.openSampleWorkbook("56315.xlsx")) {
+        try (XSSFWorkbook wb = openSampleWorkbook("56315.xlsx")) {
             Cell c = wb.getSheetAt(0).getRow(1).getCell(0);
             CellValue cv = wb.getCreationHelper().createFormulaEvaluator().evaluate(c);
             double rounded = cv.getNumberValue();
@@ -1558,7 +1532,7 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
                 Thread.sleep(10);
             }
 
-            ByteArrayOutputStream bos = new ByteArrayOutputStream(8096);
+            UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream(8096);
             wb.write(bos);
             byte[] firstSave = bos.toByteArray();
             bos.reset();
@@ -1578,17 +1552,15 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
     void bug54034() throws IOException {
         TimeZone tz = LocaleUtil.getUserTimeZone();
         LocaleUtil.setUserTimeZone(TimeZone.getTimeZone("CET"));
-        try {
-            try (Workbook wb = XSSFTestDataSamples.openSampleWorkbook("54034.xlsx")) {
-                Sheet sheet = wb.getSheet("Sheet1");
-                Row row = sheet.getRow(1);
-                Cell cell = row.getCell(2);
-                assertTrue(DateUtil.isCellDateFormatted(cell));
-
-                DataFormatter fmt = new DataFormatter();
-                assertEquals("yyyy\\-mm\\-dd\\Thh:mm", cell.getCellStyle().getDataFormatString());
-                assertEquals("2012-08-08T22:59", fmt.formatCellValue(cell));
-            }
+        try (Workbook wb = openSampleWorkbook("54034.xlsx")) {
+            Sheet sheet = wb.getSheet("Sheet1");
+            Row row = sheet.getRow(1);
+            Cell cell = row.getCell(2);
+            assertTrue(DateUtil.isCellDateFormatted(cell));
+
+            DataFormatter fmt = new DataFormatter();
+            assertEquals("yyyy\\-mm\\-dd\\Thh:mm", cell.getCellStyle().getDataFormatString());
+            assertEquals("2012-08-08T22:59", fmt.formatCellValue(cell));
         } finally {
             LocaleUtil.setUserTimeZone(tz);
         }
@@ -1597,7 +1569,7 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
 
     @Test
     void testBug53798XLSX() throws IOException {
-        try (XSSFWorkbook wb = XSSFTestDataSamples.openSampleWorkbook("53798_shiftNegative_TMPL.xlsx")) {
+        try (XSSFWorkbook wb = openSampleWorkbook("53798_shiftNegative_TMPL.xlsx")) {
             File xlsOutput = TempFile.createTempFile("testBug53798", ".xlsx");
             bug53798Work(wb, xlsOutput);
         }
@@ -1606,7 +1578,7 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
     @Disabled("Shifting rows is not yet implemented in SXSSFSheet")
     @Test
     void testBug53798XLSXStream() throws IOException {
-        try (XSSFWorkbook wb = XSSFTestDataSamples.openSampleWorkbook("53798_shiftNegative_TMPL.xlsx")) {
+        try (XSSFWorkbook wb = openSampleWorkbook("53798_shiftNegative_TMPL.xlsx")) {
             File xlsOutput = TempFile.createTempFile("testBug53798", ".xlsx");
             SXSSFWorkbook wb2 = new SXSSFWorkbook(wb);
             bug53798Work(wb2, xlsOutput);
@@ -1616,10 +1588,10 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
 
     @Test
     void testBug53798XLS() throws IOException {
-        Workbook wb = HSSFTestDataSamples.openSampleWorkbook("53798_shiftNegative_TMPL.xls");
-        File xlsOutput = TempFile.createTempFile("testBug53798", ".xls");
-        bug53798Work(wb, xlsOutput);
-        wb.close();
+        try (Workbook wb = HSSFTestDataSamples.openSampleWorkbook("53798_shiftNegative_TMPL.xls")) {
+            File xlsOutput = TempFile.createTempFile("testBug53798", ".xls");
+            bug53798Work(wb, xlsOutput);
+        }
     }
 
     /**
@@ -1627,7 +1599,7 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
      */
     @Test
     void testBug56420SumIfNPE() throws IOException {
-        try (XSSFWorkbook wb = XSSFTestDataSamples.openSampleWorkbook("56420.xlsx")) {
+        try (XSSFWorkbook wb = openSampleWorkbook("56420.xlsx")) {
 
             FormulaEvaluator evaluator = wb.getCreationHelper().createFormulaEvaluator();
 
@@ -1689,7 +1661,7 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
      */
     @Test
     void bug56702() throws IOException {
-        try (XSSFWorkbook wb = XSSFTestDataSamples.openSampleWorkbook("56702.xlsx")) {
+        try (XSSFWorkbook wb = openSampleWorkbook("56702.xlsx")) {
 
             Sheet sheet = wb.getSheetAt(0);
 
@@ -1718,7 +1690,7 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
      */
     @Test
     void bug56737() throws IOException {
-        try (Workbook wb = XSSFTestDataSamples.openSampleWorkbook("56737.xlsx")) {
+        try (Workbook wb = openSampleWorkbook("56737.xlsx")) {
 
             // Check the named range definitions
             Name nSheetScope = wb.getName("NR_To_A1");
@@ -1787,38 +1759,32 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
         }
     }
 
-    @Test
-    void testBug56688_1() throws IOException {
-        XSSFWorkbook excel = XSSFTestDataSamples.openSampleWorkbook("56688_1.xlsx");
-        checkValue(excel, "-1.0");  /* Not 0.0 because POI sees date "0" minus one month as invalid date, which is -1! */
-        excel.close();
-    }
-
-    @Test
-    void testBug56688_2() throws IOException {
-        XSSFWorkbook excel = XSSFTestDataSamples.openSampleWorkbook("56688_2.xlsx");
-        checkValue(excel, "#VALUE!");
-        excel.close();
-    }
+    @ParameterizedTest
+    @CsvSource({
+        /* Not 0.0 because POI sees date "0" minus one month as invalid date, which is -1! */
+        "56688_1.xlsx, -1.0",
+        "56688_2.xlsx, #VALUE!",
+        "56688_3.xlsx, #VALUE!",
+        "56688_4.xlsx, date"
+    })
+    void testBug56688(String fileName, String expect) throws IOException {
+        if ("date".equals(expect)) {
+            Calendar calendar = LocaleUtil.getLocaleCalendar();
+            calendar.add(Calendar.MONTH, 2);
+            double excelDate = DateUtil.getExcelDate(calendar.getTime());
+            NumberEval eval = new NumberEval(Math.floor(excelDate));
+            expect = eval.getStringValue() + ".0";
+        }
 
-    @Test
-    void testBug56688_3() throws IOException {
-        XSSFWorkbook excel = XSSFTestDataSamples.openSampleWorkbook("56688_3.xlsx");
-        checkValue(excel, "#VALUE!");
-        excel.close();
-    }
+        try (XSSFWorkbook excel = openSampleWorkbook(fileName)) {
+            XSSFFormulaEvaluator evaluator = new XSSFFormulaEvaluator(excel);
+            evaluator.evaluateAll();
 
-    @Test
-    void testBug56688_4() throws IOException {
-        XSSFWorkbook excel = XSSFTestDataSamples.openSampleWorkbook("56688_4.xlsx");
-
-        Calendar calendar = LocaleUtil.getLocaleCalendar();
-        calendar.add(Calendar.MONTH, 2);
-        double excelDate = DateUtil.getExcelDate(calendar.getTime());
-        NumberEval eval = new NumberEval(Math.floor(excelDate));
-        checkValue(excel, eval.getStringValue() + ".0");
+            XSSFCell cell = excel.getSheetAt(0).getRow(1).getCell(1);
+            CellValue value = evaluator.evaluate(cell);
 
-        excel.close();
+            assertEquals(expect, value.formatAsString());
+        }
     }
 
     /**
@@ -1827,33 +1793,33 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
      */
     @Test
     void testBug56527() throws IOException {
-        XSSFWorkbook wb = new XSSFWorkbook();
-        XSSFSheet sheet = wb.createSheet();
-        XSSFCreationHelper creationHelper = wb.getCreationHelper();
-        XSSFHyperlink hyperlink;
-
-        // Try with a cell reference
-        hyperlink = creationHelper.createHyperlink(HyperlinkType.URL);
-        sheet.addHyperlink(hyperlink);
-        hyperlink.setAddress("http://myurl");
-        hyperlink.setCellReference("B4");
-        assertEquals(3, hyperlink.getFirstRow());
-        assertEquals(1, hyperlink.getFirstColumn());
-        assertEquals(3, hyperlink.getLastRow());
-        assertEquals(1, hyperlink.getLastColumn());
-
-        // Try with explicit rows / columns
-        hyperlink = creationHelper.createHyperlink(HyperlinkType.URL);
-        sheet.addHyperlink(hyperlink);
-        hyperlink.setAddress("http://myurl");
-        hyperlink.setFirstRow(5);
-        hyperlink.setFirstColumn(3);
-
-        assertEquals(5, hyperlink.getFirstRow());
-        assertEquals(3, hyperlink.getFirstColumn());
-        assertEquals(5, hyperlink.getLastRow());
-        assertEquals(3, hyperlink.getLastColumn());
-        wb.close();
+        try (XSSFWorkbook wb = new XSSFWorkbook()) {
+            XSSFSheet sheet = wb.createSheet();
+            XSSFCreationHelper creationHelper = wb.getCreationHelper();
+            XSSFHyperlink hyperlink;
+
+            // Try with a cell reference
+            hyperlink = creationHelper.createHyperlink(HyperlinkType.URL);
+            sheet.addHyperlink(hyperlink);
+            hyperlink.setAddress("http://myurl");
+            hyperlink.setCellReference("B4");
+            assertEquals(3, hyperlink.getFirstRow());
+            assertEquals(1, hyperlink.getFirstColumn());
+            assertEquals(3, hyperlink.getLastRow());
+            assertEquals(1, hyperlink.getLastColumn());
+
+            // Try with explicit rows / columns
+            hyperlink = creationHelper.createHyperlink(HyperlinkType.URL);
+            sheet.addHyperlink(hyperlink);
+            hyperlink.setAddress("http://myurl");
+            hyperlink.setFirstRow(5);
+            hyperlink.setFirstColumn(3);
+
+            assertEquals(5, hyperlink.getFirstRow());
+            assertEquals(3, hyperlink.getFirstColumn());
+            assertEquals(5, hyperlink.getLastRow());
+            assertEquals(3, hyperlink.getLastColumn());
+        }
     }
 
     /**
@@ -1862,7 +1828,7 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
      */
     @Test
     void bug56502() throws IOException {
-        try (Workbook wb = XSSFTestDataSamples.openSampleWorkbook("56502.xlsx")) {
+        try (Workbook wb = openSampleWorkbook("56502.xlsx")) {
             Sheet sheet = wb.getSheetAt(0);
 
             Cell cFunc = sheet.getRow(3).getCell(0);
@@ -1900,7 +1866,7 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
             "Should fail as too much expansion occurs");
 
         // Check we can still parse valid files after all that
-        try (Workbook wb = XSSFTestDataSamples.openSampleWorkbook("sample.xlsx")) {
+        try (Workbook wb = openSampleWorkbook("sample.xlsx")) {
             assertEquals(3, wb.getNumberOfSheets());
         }
     }
@@ -1936,7 +1902,7 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
      */
     @Test
     void bug57176() throws IOException {
-        try (XSSFWorkbook wb = XSSFTestDataSamples.openSampleWorkbook("57176.xlsx")) {
+        try (XSSFWorkbook wb = openSampleWorkbook("57176.xlsx")) {
             CTDefinedNames definedNames = wb.getCTWorkbook().getDefinedNames();
             List<CTDefinedName> definedNameList = definedNames.getDefinedNameList();
             for (CTDefinedName defName : definedNameList) {
@@ -1967,19 +1933,9 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
         assertThrows(XLSBUnsupportedException.class, () -> WorkbookFactory.create(xlsbFile), ".xlsb files not supported");
     }
 
-    private void checkValue(XSSFWorkbook excel, String expect) {
-        XSSFFormulaEvaluator evaluator = new XSSFFormulaEvaluator(excel);
-        evaluator.evaluateAll();
-
-        XSSFCell cell = excel.getSheetAt(0).getRow(1).getCell(1);
-        CellValue value = evaluator.evaluate(cell);
-
-        assertEquals(expect, value.formatAsString());
-    }
-
     @Test
     void testBug57196() throws IOException {
-        try (Workbook wb = XSSFTestDataSamples.openSampleWorkbook("57196.xlsx")) {
+        try (Workbook wb = openSampleWorkbook("57196.xlsx")) {
             Sheet sheet = wb.getSheet("Feuil1");
             Row mod = sheet.getRow(1);
             mod.getCell(1).setCellValue(3);
@@ -1992,30 +1948,30 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
 
     @Test
     void test57196_Detail() throws IOException {
-        XSSFWorkbook wb = new XSSFWorkbook();
-        XSSFSheet sheet = wb.createSheet("Sheet1");
-        XSSFRow row = sheet.createRow(0);
-        XSSFCell cell = row.createCell(0);
-        cell.setCellFormula("DEC2HEX(HEX2DEC(O8)-O2+D2)");
-        XSSFFormulaEvaluator fe = new XSSFFormulaEvaluator(wb);
-        CellValue cv = fe.evaluate(cell);
+        try (XSSFWorkbook wb = new XSSFWorkbook()) {
+            XSSFSheet sheet = wb.createSheet("Sheet1");
+            XSSFRow row = sheet.createRow(0);
+            XSSFCell cell = row.createCell(0);
+            cell.setCellFormula("DEC2HEX(HEX2DEC(O8)-O2+D2)");
+            XSSFFormulaEvaluator fe = new XSSFFormulaEvaluator(wb);
+            CellValue cv = fe.evaluate(cell);
 
-        assertNotNull(cv);
-        wb.close();
+            assertNotNull(cv);
+        }
     }
 
     @Test
     void test57196_Detail2() throws IOException {
-        XSSFWorkbook wb = new XSSFWorkbook();
-        XSSFSheet sheet = wb.createSheet("Sheet1");
-        XSSFRow row = sheet.createRow(0);
-        XSSFCell cell = row.createCell(0);
-        cell.setCellFormula("DEC2HEX(O2+D2)");
-        XSSFFormulaEvaluator fe = new XSSFFormulaEvaluator(wb);
-        CellValue cv = fe.evaluate(cell);
+        try (XSSFWorkbook wb = new XSSFWorkbook()) {
+            XSSFSheet sheet = wb.createSheet("Sheet1");
+            XSSFRow row = sheet.createRow(0);
+            XSSFCell cell = row.createCell(0);
+            cell.setCellFormula("DEC2HEX(O2+D2)");
+            XSSFFormulaEvaluator fe = new XSSFFormulaEvaluator(wb);
+            CellValue cv = fe.evaluate(cell);
 
-        assertNotNull(cv);
-        wb.close();
+            assertNotNull(cv);
+        }
     }
 
     @ParameterizedTest
@@ -2081,7 +2037,7 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
 
             // Try to write-out and read again, should only work
             //  in read-write mode, not read-only mode
-            try (XSSFWorkbook wb2 = XSSFTestDataSamples.writeOutAndReadBack(wb1)) {
+            try (XSSFWorkbook wb2 = writeOutAndReadBack(wb1)) {
                 if (access == PackageAccess.READ) {
                     fail("Shouln't be able to write from read-only mode");
                 }
@@ -2110,7 +2066,7 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
      */
     @Test
     void bug57535() throws IOException {
-        try (Workbook wb = XSSFTestDataSamples.openSampleWorkbook("57535.xlsx")) {
+        try (Workbook wb = openSampleWorkbook("57535.xlsx")) {
             FormulaEvaluator evaluator = wb.getCreationHelper().createFormulaEvaluator();
             evaluator.clearAllCachedResultValues();
 
@@ -2130,13 +2086,13 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
 
     @Test
     void test57165() throws IOException {
-        try (XSSFWorkbook wb = XSSFTestDataSamples.openSampleWorkbook("57171_57163_57165.xlsx")) {
+        try (XSSFWorkbook wb = openSampleWorkbook("57171_57163_57165.xlsx")) {
             removeAllSheetsBut(3, wb);
             // Throws exception here
             assertDoesNotThrow(() -> wb.cloneSheet(0));
             wb.setSheetName(1, "New Sheet");
 
-            try (XSSFWorkbook wbBack = XSSFTestDataSamples.writeOutAndReadBack(wb)) {
+            try (XSSFWorkbook wbBack = writeOutAndReadBack(wb)) {
                 assertNotNull(wbBack.getSheet("New Sheet"));
             }
         }
@@ -2144,13 +2100,13 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
 
     @Test
     void test57165_create() throws IOException {
-        try (XSSFWorkbook wb = XSSFTestDataSamples.openSampleWorkbook("57171_57163_57165.xlsx")) {
+        try (XSSFWorkbook wb = openSampleWorkbook("57171_57163_57165.xlsx")) {
             removeAllSheetsBut(3, wb);
             // Throws exception here
             assertDoesNotThrow(() -> wb.createSheet("newsheet"));
             wb.setSheetName(1, "New Sheet");
 
-            try (XSSFWorkbook wbBack = XSSFTestDataSamples.writeOutAndReadBack(wb)) {
+            try (XSSFWorkbook wbBack = writeOutAndReadBack(wb)) {
                 assertNotNull(wbBack.getSheet("New Sheet"));
             }
         }
@@ -2235,7 +2191,7 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
 
     @Test
     void test56467() throws IOException {
-        try (Workbook wb = XSSFTestDataSamples.openSampleWorkbook("picture.xlsx")) {
+        try (Workbook wb = openSampleWorkbook("picture.xlsx")) {
             Sheet orig = wb.getSheetAt(0);
             assertNotNull(orig);
 
@@ -2258,12 +2214,12 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
     @Test
     @Disabled("XMLBeans namespace mis-match on ooxml-strict files")
     void test57699() throws IOException {
-        try (XSSFWorkbook wb = XSSFTestDataSamples.openSampleWorkbook("sample.strict.xlsx")) {
+        try (XSSFWorkbook wb = openSampleWorkbook("sample.strict.xlsx")) {
             assertEquals(3, wb.getNumberOfSheets());
             // TODO Check sheet contents
             // TODO Check formula evaluation
 
-            try (XSSFWorkbook wbBack = XSSFTestDataSamples.writeOutAndReadBack(wb)) {
+            try (XSSFWorkbook wbBack = writeOutAndReadBack(wb)) {
                 assertEquals(3, wbBack.getNumberOfSheets());
                 // TODO Re-check sheet contents
                 // TODO Re-check formula evaluation
@@ -2273,13 +2229,14 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
 
     @Test
     void testBug56295_MergeXlslsWithStyles() throws IOException {
-        XSSFWorkbook xlsToAppendWorkbook = XSSFTestDataSamples.openSampleWorkbook("56295.xlsx");
-        XSSFSheet sheet = xlsToAppendWorkbook.getSheetAt(0);
-        XSSFRow srcRow = sheet.getRow(0);
-        XSSFCell oldCell = srcRow.getCell(0);
-        XSSFCellStyle cellStyle = oldCell.getCellStyle();
+        try (XSSFWorkbook xlsToAppendWorkbook = openSampleWorkbook("56295.xlsx");
+             XSSFWorkbook targetWorkbook = new XSSFWorkbook()) {
+            XSSFSheet sheet = xlsToAppendWorkbook.getSheetAt(0);
+            XSSFRow srcRow = sheet.getRow(0);
+            XSSFCell oldCell = srcRow.getCell(0);
+            XSSFCellStyle cellStyle = oldCell.getCellStyle();
 
-        checkStyle(cellStyle);
+            checkStyle(cellStyle);
 
 //        StylesTable table = xlsToAppendWorkbook.getStylesSource();
 //        List<XSSFCellFill> fills = table.getFills();
@@ -2287,33 +2244,25 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
 //        for(XSSFCellFill fill : fills) {
 //        	System.out.println("Fill: " + fill.getFillBackgroundColor() + "/" + fill.getFillForegroundColor());
 //        }
-        xlsToAppendWorkbook.close();
-
-        XSSFWorkbook targetWorkbook = new XSSFWorkbook();
-        XSSFSheet newSheet = targetWorkbook.createSheet(sheet.getSheetName());
-        XSSFRow destRow = newSheet.createRow(0);
-        XSSFCell newCell = destRow.createCell(0);
-
-        //newCell.getCellStyle().cloneStyleFrom(cellStyle);
-        CellStyle newCellStyle = targetWorkbook.createCellStyle();
-        newCellStyle.cloneStyleFrom(cellStyle);
-        newCell.setCellStyle(newCellStyle);
-        checkStyle(newCell.getCellStyle());
-        newCell.setCellValue(oldCell.getStringCellValue());
-
-//        OutputStream os = new FileOutputStream("output.xlsm");
-//        try {
-//        	targetWorkbook.write(os);
-//        } finally {
-//        	os.close();
-//        }
+            xlsToAppendWorkbook.close();
+
+            XSSFSheet newSheet = targetWorkbook.createSheet(sheet.getSheetName());
+            XSSFRow destRow = newSheet.createRow(0);
+            XSSFCell newCell = destRow.createCell(0);
 
-        XSSFWorkbook wbBack = XSSFTestDataSamples.writeOutAndReadBack(targetWorkbook);
-        XSSFCellStyle styleBack = wbBack.getSheetAt(0).getRow(0).getCell(0).getCellStyle();
-        checkStyle(styleBack);
+            //newCell.getCellStyle().cloneStyleFrom(cellStyle);
+            CellStyle newCellStyle = targetWorkbook.createCellStyle();
+            newCellStyle.cloneStyleFrom(cellStyle);
+            newCell.setCellStyle(newCellStyle);
+            checkStyle(newCell.getCellStyle());
+            newCell.setCellValue(oldCell.getStringCellValue());
 
-        targetWorkbook.close();
-        wbBack.close();
+            try (XSSFWorkbook wbBack = writeOutAndReadBack(targetWorkbook)) {
+                XSSFCellStyle styleBack = wbBack.getSheetAt(0).getRow(0).getCell(0).getCellStyle();
+                checkStyle(styleBack);
+
+            }
+        }
     }
 
     /**
@@ -2323,27 +2272,25 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
      */
     @Test
     void testBug57826() throws IOException {
-        XSSFWorkbook workbook = XSSFTestDataSamples.openSampleWorkbook("57826.xlsx");
-
-        assertTrue(workbook.getNumberOfSheets() >= 1, "no sheets in workbook");
-        XSSFSheet sheet = workbook.getSheetAt(0);
+        try (XSSFWorkbook workbook = openSampleWorkbook("57826.xlsx")) {
+            assertTrue(workbook.getNumberOfSheets() >= 1, "no sheets in workbook");
+            XSSFSheet sheet = workbook.getSheetAt(0);
 
-        XSSFDrawing drawing = sheet.getDrawingPatriarch();
-        assertNotNull(drawing);
+            XSSFDrawing drawing = sheet.getDrawingPatriarch();
+            assertNotNull(drawing);
 
-        List<XSSFShape> shapes = drawing.getShapes();
-        assertEquals(1, shapes.size());
-        assertTrue(shapes.get(0) instanceof XSSFSimpleShape);
+            List<XSSFShape> shapes = drawing.getShapes();
+            assertEquals(1, shapes.size());
+            assertTrue(shapes.get(0) instanceof XSSFSimpleShape);
 
-        XSSFSimpleShape shape = (XSSFSimpleShape) shapes.get(0);
+            XSSFSimpleShape shape = (XSSFSimpleShape) shapes.get(0);
 
-        // Used to throw a NPE
-        String text = shape.getText();
+            // Used to throw a NPE
+            String text = shape.getText();
 
-        // No bulleting info included
-        assertEquals("test ok", text);
-
-        workbook.close();
+            // No bulleting info included
+            assertEquals("test ok", text);
+        }
     }
 
     private void checkStyle(XSSFCellStyle cellStyle) {
@@ -2363,20 +2310,19 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
 
     @Test
     void bug57642() throws IOException {
-        XSSFWorkbook wb = new XSSFWorkbook();
-        XSSFSheet s = wb.createSheet("TestSheet");
-        XSSFCell c = s.createRow(0).createCell(0);
-        c.setCellFormula("ISERROR(TestSheet!A1)");
-        c = s.createRow(1).createCell(1);
-        c.setCellFormula("ISERROR(B2)");
-
-        wb.setSheetName(0, "CSN");
-        c = s.getRow(0).getCell(0);
-        assertEquals("ISERROR(CSN!A1)", c.getCellFormula());
-        c = s.getRow(1).getCell(1);
-        assertEquals("ISERROR(B2)", c.getCellFormula());
+        try (XSSFWorkbook wb = new XSSFWorkbook()) {
+            XSSFSheet s = wb.createSheet("TestSheet");
+            XSSFCell c = s.createRow(0).createCell(0);
+            c.setCellFormula("ISERROR(TestSheet!A1)");
+            c = s.createRow(1).createCell(1);
+            c.setCellFormula("ISERROR(B2)");
 
-        wb.close();
+            wb.setSheetName(0, "CSN");
+            c = s.getRow(0).getCell(0);
+            assertEquals("ISERROR(CSN!A1)", c.getCellFormula());
+            c = s.getRow(1).getCell(1);
+            assertEquals("ISERROR(B2)", c.getCellFormula());
+        }
     }
 
     /**
@@ -2386,47 +2332,42 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
     @Test
     void bug57880() throws IOException {
         int numStyles = 33000;
-        XSSFWorkbook wb = new XSSFWorkbook();
-        for (int i = 1; i < numStyles; i++) {
-            // Create a style and use it
-            XSSFCellStyle style = wb.createCellStyle();
-            assertEquals(i, style.getUIndex());
-        }
-        assertEquals(numStyles, wb.getNumCellStyles());
+        File file;
+        try (XSSFWorkbook wb = new XSSFWorkbook()) {
+            for (int i = 1; i < numStyles; i++) {
+                // Create a style and use it
+                XSSFCellStyle style = wb.createCellStyle();
+                assertEquals(i, style.getUIndex());
+            }
+            assertEquals(numStyles, wb.getNumCellStyles());
 
-        // avoid OOM in Gump run
-        File file = XSSFTestDataSamples.writeOutAndClose(wb, "bug57880");
-        //noinspection UnusedAssignment
-        wb = null;
-        // Garbage collection may happen here
+            // avoid OOM in Gump run
+            file = XSSFTestDataSamples.writeOutAndClose(wb, "bug57880");
+        }
 
         // avoid zip bomb detection
         double ratio = ZipSecureFile.getMinInflateRatio();
         ZipSecureFile.setMinInflateRatio(0.00005);
-        wb = XSSFTestDataSamples.readBackAndDelete(file);
-        ZipSecureFile.setMinInflateRatio(ratio);
-
-        //Assume identical cell styles aren't consolidated
-        //If XSSFWorkbooks ever implicitly optimize/consolidate cell styles (such as when the workbook is written to disk)
-        //then this unit test should be updated
-        assertEquals(numStyles, wb.getNumCellStyles());
-        for (int i = 1; i < numStyles; i++) {
-            XSSFCellStyle style = wb.getCellStyleAt(i);
-            assertNotNull(style);
-            assertEquals(i, style.getUIndex());
+        try (XSSFWorkbook wb = XSSFTestDataSamples.readBackAndDelete(file)) {
+            ZipSecureFile.setMinInflateRatio(ratio);
+
+            //Assume identical cell styles aren't consolidated
+            //If XSSFWorkbooks ever implicitly optimize/consolidate cell styles (such as when the workbook is written to disk)
+            //then this unit test should be updated
+            assertEquals(numStyles, wb.getNumCellStyles());
+            for (int i = 1; i < numStyles; i++) {
+                XSSFCellStyle style = wb.getCellStyleAt(i);
+                assertNotNull(style);
+                assertEquals(i, style.getUIndex());
+            }
         }
-        wb.close();
     }
 
 
-    @Test
-    void test56574() throws IOException {
-        runTest56574(false);
-        runTest56574(true);
-    }
-
-    private void runTest56574(boolean createRow) throws IOException {
-        try (XSSFWorkbook wb = XSSFTestDataSamples.openSampleWorkbook("56574.xlsx")) {
+    @ParameterizedTest
+    @ValueSource(booleans = { false, true})
+    void test56574(boolean createRow) throws IOException {
+        try (XSSFWorkbook wb = openSampleWorkbook("56574.xlsx")) {
 
             Sheet sheet = wb.getSheet("Func");
             assertNotNull(sheet);
@@ -2475,14 +2416,13 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
             CalculationChain chain = wb.getCalculationChain();
             checkCellsAreGone(chain);
 
-            XSSFWorkbook wbBack = XSSFTestDataSamples.writeOutAndReadBack(wb);
-            Sheet sheetBack = wbBack.getSheet("Func");
-            assertNotNull(sheetBack);
-
-            chain = wbBack.getCalculationChain();
-            checkCellsAreGone(chain);
+            try (XSSFWorkbook wbBack = writeOutAndReadBack(wb)) {
+                Sheet sheetBack = wbBack.getSheet("Func");
+                assertNotNull(sheetBack);
 
-            wbBack.close();
+                chain = wbBack.getCalculationChain();
+                checkCellsAreGone(chain);
+            }
         }
     }
 
@@ -2502,14 +2442,14 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
      */
     @Test
     void bug57181() throws IOException {
-        try (XSSFWorkbook wb = XSSFTestDataSamples.openSampleWorkbook("57181.xlsm")) {
+        try (XSSFWorkbook wb = openSampleWorkbook("57181.xlsm")) {
             assertEquals(9, wb.getNumberOfSheets());
         }
     }
 
     @Test
     void bug52111() throws IOException {
-        try (Workbook wb = XSSFTestDataSamples.openSampleWorkbook("Intersection-52111-xssf.xlsx")) {
+        try (Workbook wb = openSampleWorkbook("Intersection-52111-xssf.xlsx")) {
             Sheet s = wb.getSheetAt(0);
             assertFormula(wb, s.getRow(2).getCell(0), "(C2:D3 D3:E4)", "4.0");
             assertFormula(wb, s.getRow(6).getCell(0), "Tabelle2!E:E Tabelle2!11:11", "5.0");
@@ -2519,7 +2459,7 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
 
     @Test
     void test48962() throws IOException {
-        try (Workbook wb = XSSFTestDataSamples.openSampleWorkbook("48962.xlsx")) {
+        try (Workbook wb = openSampleWorkbook("48962.xlsx")) {
             Sheet sh = wb.getSheetAt(0);
             Row row = sh.getRow(1);
             Cell cell = row.getCell(0);
@@ -2544,7 +2484,7 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
 
     @Test
     void test50755_workday_formula_example() throws IOException {
-        try (Workbook wb = XSSFTestDataSamples.openSampleWorkbook("50755_workday_formula_example.xlsx")) {
+        try (Workbook wb = openSampleWorkbook("50755_workday_formula_example.xlsx")) {
             Sheet sheet = wb.getSheet("Sheet1");
             for (Row aRow : sheet) {
                 Cell cell = aRow.getCell(1);
@@ -2559,25 +2499,17 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
         }
     }
 
-    @Test
-    void test51626() throws IOException {
-        Workbook wb = XSSFTestDataSamples.openSampleWorkbook("51626.xlsx");
-        assertNotNull(wb);
-        wb.close();
-
-        InputStream stream = HSSFTestDataSamples.openSampleFileStream("51626.xlsx");
-        wb = WorkbookFactory.create(stream);
-        stream.close();
-        wb.close();
-
-        wb = XSSFTestDataSamples.openSampleWorkbook("51626_contact.xlsx");
-        assertNotNull(wb);
-        wb.close();
+    @ParameterizedTest
+    @ValueSource(strings = { "51626.xlsx", "51626_contact.xlsx"})
+    void test51626(String fileName) throws IOException {
+        try (Workbook wb = openSampleWorkbook(fileName)) {
+            assertNotNull(wb);
+        }
 
-        stream = HSSFTestDataSamples.openSampleFileStream("51626_contact.xlsx");
-        wb = WorkbookFactory.create(stream);
-        stream.close();
-        wb.close();
+        try (InputStream stream = HSSFTestDataSamples.openSampleFileStream(fileName);
+             Workbook wb = WorkbookFactory.create(stream)) {
+            assertNotNull(wb);
+        }
     }
 
     @Disabled("this test is only for manual verification, as we can't test if the cell is visible in Excel")
@@ -2599,7 +2531,7 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
 
     @Test
     void test53105() throws IOException {
-        try (Workbook wb = XSSFTestDataSamples.openSampleWorkbook("53105.xlsx")) {
+        try (Workbook wb = openSampleWorkbook("53105.xlsx")) {
             assertNotNull(wb);
 
 
@@ -2616,7 +2548,7 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
 
     @Test
     void test58315() throws IOException {
-        try (Workbook wb = XSSFTestDataSamples.openSampleWorkbook("58315.xlsx")) {
+        try (Workbook wb = openSampleWorkbook("58315.xlsx")) {
             Cell cell = wb.getSheetAt(0).getRow(0).getCell(0);
             assertNotNull(cell);
             StringBuilder tmpCellContent = new StringBuilder(cell.getStringCellValue());
@@ -2635,7 +2567,7 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
 
     @Test
     void test55406() throws IOException {
-        try (Workbook wb = XSSFTestDataSamples.openSampleWorkbook("55406_Conditional_formatting_sample.xlsx")) {
+        try (Workbook wb = openSampleWorkbook("55406_Conditional_formatting_sample.xlsx")) {
             Sheet sheet = wb.getSheetAt(0);
             Cell cellA1 = sheet.getRow(0).getCell(0);
             Cell cellA2 = sheet.getRow(1).getCell(0);
@@ -2662,45 +2594,43 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
 
     @Test
     void test51998() throws IOException {
-        Workbook wb = XSSFTestDataSamples.openSampleWorkbook("51998.xlsx");
+        try (Workbook wb = openSampleWorkbook("51998.xlsx")) {
+            Set<String> sheetNames = new HashSet<>();
 
-        Set<String> sheetNames = new HashSet<>();
+            for (int sheetNum = 0; sheetNum < wb.getNumberOfSheets(); sheetNum++) {
+                sheetNames.add(wb.getSheetName(sheetNum));
+            }
 
-        for (int sheetNum = 0; sheetNum < wb.getNumberOfSheets(); sheetNum++) {
-            sheetNames.add(wb.getSheetName(sheetNum));
-        }
+            for (String sheetName : sheetNames) {
+                int sheetIndex = wb.getSheetIndex(sheetName);
 
-        for (String sheetName : sheetNames) {
-            int sheetIndex = wb.getSheetIndex(sheetName);
+                wb.removeSheetAt(sheetIndex);
 
-            wb.removeSheetAt(sheetIndex);
+                Sheet newSheet = wb.createSheet();
+                //Sheet newSheet = wb.createSheet(sheetName);
+                int newSheetIndex = wb.getSheetIndex(newSheet);
+                wb.setSheetName(newSheetIndex, sheetName);
+                wb.setSheetOrder(sheetName, sheetIndex);
+            }
 
-            Sheet newSheet = wb.createSheet();
-            //Sheet newSheet = wb.createSheet(sheetName);
-            int newSheetIndex = wb.getSheetIndex(newSheet);
-            wb.setSheetName(newSheetIndex, sheetName);
-            wb.setSheetOrder(sheetName, sheetIndex);
+            try (Workbook wbBack = writeOutAndReadBack(wb)) {
+                assertNotNull(wbBack);
+            }
         }
-
-        Workbook wbBack = XSSFTestDataSamples.writeOutAndReadBack(wb);
-        wb.close();
-
-        assertNotNull(wbBack);
-        wbBack.close();
     }
 
     @Test
     void test58731() throws IOException {
-        try (Workbook wb = XSSFTestDataSamples.openSampleWorkbook("58731.xlsx")) {
+        Object[][] bookData = {
+            {"Head First Java", "Kathy Serria", 79},
+            {"Effective Java", "Joshua Bloch", 36},
+            {"Clean Code", "Robert martin", 42},
+            {"Thinking in Java", "Bruce Eckel", 35},
+        };
+
+        try (Workbook wb = openSampleWorkbook("58731.xlsx")) {
             Sheet sheet = wb.createSheet("Java Books");
 
-            Object[][] bookData = {
-                    {"Head First Java", "Kathy Serria", 79},
-                    {"Effective Java", "Joshua Bloch", 36},
-                    {"Clean Code", "Robert martin", 42},
-                    {"Thinking in Java", "Bruce Eckel", 35},
-            };
-
             int rowCount = 0;
             for (Object[] aBook : bookData) {
                 Row row = sheet.createRow(rowCount++);
@@ -2716,7 +2646,7 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
                 }
             }
 
-            try (Workbook wb2 = XSSFTestDataSamples.writeOutAndReadBack(wb)) {
+            try (Workbook wb2 = writeOutAndReadBack(wb)) {
                 sheet = wb2.getSheet("Java Books");
                 assertNotNull(sheet.getRow(0));
                 assertNotNull(sheet.getRow(0).getCell(0));
@@ -2733,14 +2663,14 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
      */
     @Test
     void test58760() throws IOException {
-        Workbook wb1 = XSSFTestDataSamples.openSampleWorkbook("58760.xlsx");
-        assertEquals(1, wb1.getNumberOfSheets());
-        assertEquals("Sheet1", wb1.getSheetName(0));
-        Workbook wb2 = XSSFTestDataSamples.writeOutAndReadBack(wb1);
-        assertEquals(1, wb2.getNumberOfSheets());
-        assertEquals("Sheet1", wb2.getSheetName(0));
-        wb2.close();
-        wb1.close();
+        try (Workbook wb1 = openSampleWorkbook("58760.xlsx")) {
+            assertEquals(1, wb1.getNumberOfSheets());
+            assertEquals("Sheet1", wb1.getSheetName(0));
+            try (Workbook wb2 = writeOutAndReadBack(wb1)) {
+                assertEquals(1, wb2.getNumberOfSheets());
+                assertEquals("Sheet1", wb2.getSheetName(0));
+            }
+        }
     }
 
     @Test
@@ -2755,7 +2685,7 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
 
         DataFormatter formatter = new DataFormatter(true);
 
-        try (XSSFWorkbook wb = XSSFTestDataSamples.openSampleWorkbook("57236.xlsx")) {
+        try (XSSFWorkbook wb = openSampleWorkbook("57236.xlsx")) {
             for (int sheetNum = 0; sheetNum < wb.getNumberOfSheets(); sheetNum++) {
                 Sheet sheet = wb.getSheetAt(sheetNum);
                 for (int rowNum = sheet.getFirstRowNum(); rowNum < sheet.getLastRowNum(); rowNum++) {
@@ -2771,41 +2701,27 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
         }
     }
 
-    /**
-     * helper function for {@link #test58043()}
-     * Side-effects: closes the provided workbook!
-     *
-     * @param workbook the workbook to save for manual checking
-     * @param outputFile the output file location to save the workbook to
-     */
-    private void saveRotatedTextExample(Workbook workbook, File outputFile) throws IOException {
-        Sheet sheet = workbook.createSheet();
-        Row row = sheet.createRow((short) 0);
-
-        Cell cell = row.createCell(0);
-
-        cell.setCellValue("Unsuccessful rotated text.");
-
-        CellStyle style = workbook.createCellStyle();
-        style.setRotation((short) -90);
-
-        cell.setCellStyle(style);
+    @ParameterizedTest()
+    @CsvSource({ "false, rotated.xls", "true, rotated.xlsx" })
+    @Disabled("Creates files for checking results manually, actual values are tested in Test*CellStyle")
+    void test58043(boolean xssf, String fileName) throws IOException {
+        try (Workbook wb = WorkbookFactory.create(xssf)) {
+            Sheet sheet = wb.createSheet();
+            Row row = sheet.createRow((short) 0);
+            Cell cell = row.createCell(0);
+            cell.setCellValue("Unsuccessful rotated text.");
 
-        OutputStream fos = new FileOutputStream(outputFile);
-        workbook.write(fos);
-        fos.close();
-        workbook.close();
-    }
+            CellStyle style = wb.createCellStyle();
+            style.setRotation((short) -90);
+            cell.setCellStyle(style);
 
-    @Disabled("Creates files for checking results manually, actual values are tested in Test*CellStyle")
-    void test58043() throws IOException {
-        saveRotatedTextExample(new HSSFWorkbook(), TempFile.createTempFile("rotated", ".xls"));
-        saveRotatedTextExample(new XSSFWorkbook(), TempFile.createTempFile("rotated", ".xlsx"));
+            XSSFTestDataSamples.writeOut(wb, fileName);
+        }
     }
 
     @Test
     void test59132() throws IOException {
-        try (Workbook workbook = XSSFTestDataSamples.openSampleWorkbook("59132.xlsx")) {
+        try (Workbook workbook = openSampleWorkbook("59132.xlsx")) {
             Sheet worksheet = workbook.getSheet("sheet1");
 
             // B3
@@ -2848,51 +2764,51 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
     @Disabled("bug 59442")
     @Test
     void testSetRGBBackgroundColor() throws IOException {
-        XSSFWorkbook workbook = new XSSFWorkbook();
-        XSSFCell cell = workbook.createSheet().createRow(0).createCell(0);
-
-        XSSFColor color = new XSSFColor(java.awt.Color.RED, workbook.getStylesSource().getIndexedColors());
-        XSSFCellStyle style = workbook.createCellStyle();
-        style.setFillForegroundColor(color);
-        style.setFillPattern(FillPatternType.SOLID_FOREGROUND);
-        cell.setCellStyle(style);
-
-        // Everything is fine at this point, cell is red
-        XSSFColor actual = cell.getCellStyle().getFillBackgroundColorColor();
-        assertNull(actual);
-        actual = cell.getCellStyle().getFillForegroundColorColor();
-        assertNotNull(actual);
-        assertEquals(color.getARGBHex(), actual.getARGBHex());
-
-        Map<String, Object> properties = new HashMap<>();
-        properties.put(CellUtil.BORDER_BOTTOM, BorderStyle.THIN);
-        CellUtil.setCellStyleProperties(cell, properties);
-
-        // Now the cell is all black
-        actual = cell.getCellStyle().getFillBackgroundColorColor();
-        assertNotNull(actual);
-        assertNull(actual.getARGBHex());
-        actual = cell.getCellStyle().getFillForegroundColorColor();
-        assertNotNull(actual);
-        assertEquals(color.getARGBHex(), actual.getARGBHex());
-
-        XSSFWorkbook nwb = XSSFTestDataSamples.writeOutAndReadBack(workbook);
-        workbook.close();
-        XSSFCell ncell = nwb.getSheetAt(0).getRow(0).getCell(0);
-        XSSFColor ncolor = new XSSFColor(java.awt.Color.RED, workbook.getStylesSource().getIndexedColors());
-
-        // Now the cell is all black
-        XSSFColor nactual = ncell.getCellStyle().getFillBackgroundColorColor();
-        assertNotNull(nactual);
-        assertEquals(ncolor.getARGBHex(), nactual.getARGBHex());
-
-        nwb.close();
+        try (XSSFWorkbook workbook = new XSSFWorkbook()) {
+            XSSFCell cell = workbook.createSheet().createRow(0).createCell(0);
+
+            XSSFColor color = new XSSFColor(java.awt.Color.RED, workbook.getStylesSource().getIndexedColors());
+            XSSFCellStyle style = workbook.createCellStyle();
+            style.setFillForegroundColor(color);
+            style.setFillPattern(FillPatternType.SOLID_FOREGROUND);
+            cell.setCellStyle(style);
+
+            // Everything is fine at this point, cell is red
+            XSSFColor actual = cell.getCellStyle().getFillBackgroundColorColor();
+            assertNull(actual);
+            actual = cell.getCellStyle().getFillForegroundColorColor();
+            assertNotNull(actual);
+            assertEquals(color.getARGBHex(), actual.getARGBHex());
+
+            Map<String, Object> properties = new HashMap<>();
+            properties.put(CellUtil.BORDER_BOTTOM, BorderStyle.THIN);
+            CellUtil.setCellStyleProperties(cell, properties);
+
+            // Now the cell is all black
+            actual = cell.getCellStyle().getFillBackgroundColorColor();
+            assertNotNull(actual);
+            assertNull(actual.getARGBHex());
+            actual = cell.getCellStyle().getFillForegroundColorColor();
+            assertNotNull(actual);
+            assertEquals(color.getARGBHex(), actual.getARGBHex());
+
+            try (XSSFWorkbook nwb = writeOutAndReadBack(workbook)) {
+                XSSFCell ncell = nwb.getSheetAt(0).getRow(0).getCell(0);
+                XSSFColor ncolor = new XSSFColor(java.awt.Color.RED, workbook.getStylesSource().getIndexedColors());
+
+                // Now the cell is all black
+                XSSFColor nactual = ncell.getCellStyle().getFillBackgroundColorColor();
+                assertNotNull(nactual);
+                assertEquals(ncolor.getARGBHex(), nactual.getARGBHex());
+
+            }
+        }
     }
 
     @Disabled("currently fails on POI 3.15 beta 2")
     @Test
     void test55273() throws IOException {
-        try (Workbook wb = XSSFTestDataSamples.openSampleWorkbook("ExcelTables.xlsx")) {
+        try (Workbook wb = openSampleWorkbook("ExcelTables.xlsx")) {
             Sheet sheet = wb.getSheet("ExcelTable");
 
             Name name = wb.getName("TableAsRangeName");
@@ -2910,7 +2826,7 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
 
     @Test
     void test57523() throws IOException {
-        try (Workbook wb = XSSFTestDataSamples.openSampleWorkbook("57523.xlsx")) {
+        try (Workbook wb = openSampleWorkbook("57523.xlsx")) {
             Sheet sheet = wb.getSheet("Attribute Master");
             Row row = sheet.getRow(15);
 
@@ -2930,7 +2846,7 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
      */
     @Test
     void noRowNumbers59746() throws IOException {
-        try (Workbook wb = XSSFTestDataSamples.openSampleWorkbook("59746_NoRowNums.xlsx")) {
+        try (Workbook wb = openSampleWorkbook("59746_NoRowNums.xlsx")) {
             Sheet sheet = wb.getSheetAt(0);
             assertTrue(sheet.getLastRowNum() > 20, "Last row num: " + sheet.getLastRowNum());
             assertEquals("Checked", sheet.getRow(0).getCell(0).getStringCellValue());
@@ -2944,7 +2860,7 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
 
     @Test
     void testWorkdayFunction() throws IOException {
-        try (XSSFWorkbook workbook = XSSFTestDataSamples.openSampleWorkbook("59106.xlsx")) {
+        try (XSSFWorkbook workbook = openSampleWorkbook("59106.xlsx")) {
             XSSFSheet sheet = workbook.getSheet("Test");
             Row row = sheet.getRow(1);
             Cell cell = row.getCell(0);
@@ -3003,7 +2919,7 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
      */
     @Test
     void drawingNumbersAlreadyTaken_60255() throws IOException {
-        try (Workbook wb = XSSFTestDataSamples.openSampleWorkbook("60255_extra_drawingparts.xlsx")) {
+        try (Workbook wb = openSampleWorkbook("60255_extra_drawingparts.xlsx")) {
             assertEquals(4, wb.getNumberOfSheets());
 
             // Sheet 3 starts with a drawing
@@ -3023,7 +2939,7 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
             assertNotNull(sheet.getDrawingPatriarch());
 
             // Save and check
-            Workbook wbBack = XSSFTestDataSamples.writeOutAndReadBack(wb);
+            Workbook wbBack = writeOutAndReadBack(wb);
             assertEquals(5, wbBack.getNumberOfSheets());
 
             // Sheets 3 and 5 now
@@ -3042,52 +2958,50 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
 
     @Test
     void test53611() throws IOException {
-        Workbook wb = new XSSFWorkbook();
-        Sheet sheet = wb.createSheet("test");
-        Row row = sheet.createRow(1);
-        Cell cell = row.createCell(1);
-        cell.setCellValue("blabla");
-
-        //0 1 2 3 4 5 6 7
-        //A B C D E F G H
-        row = sheet.createRow(4);
-        cell = row.createCell(7);
-        cell.setCellValue("blabla");
+        try (Workbook wb = new XSSFWorkbook()) {
+            Sheet sheet = wb.createSheet("test");
+            Row row = sheet.createRow(1);
+            Cell cell = row.createCell(1);
+            cell.setCellValue("blabla");
 
-        // we currently only populate the dimension during writing out
-        // to avoid having to iterate all rows/cells in each add/remove of a row or cell
-        wb.write(new NullOutputStream());
+            //0 1 2 3 4 5 6 7
+            //A B C D E F G H
+            row = sheet.createRow(4);
+            cell = row.createCell(7);
+            cell.setCellValue("blabla");
 
-        assertEquals("B2:H5", ((XSSFSheet) sheet).getCTWorksheet().getDimension().getRef());
+            // we currently only populate the dimension during writing out
+            // to avoid having to iterate all rows/cells in each add/remove of a row or cell
+            wb.write(NULL_OUTPUT_STREAM);
 
-        wb.close();
+            assertEquals("B2:H5", ((XSSFSheet) sheet).getCTWorksheet().getDimension().getRef());
+        }
     }
 
     @Test
     void test61798() throws IOException {
-        Workbook wb = new XSSFWorkbook();
-        Sheet sheet = wb.createSheet("test");
-        Row row = sheet.createRow(1);
-        Cell cell = row.createCell(1);
-        cell.setCellValue("blabla");
-
-        row = sheet.createRow(4);
-        // Allowable column range for EXCEL2007 is (0..16383) or ('A'..'XDF')
-        cell = row.createCell(16383);
-        cell.setCellValue("blabla");
+        try (Workbook wb = new XSSFWorkbook()) {
+            Sheet sheet = wb.createSheet("test");
+            Row row = sheet.createRow(1);
+            Cell cell = row.createCell(1);
+            cell.setCellValue("blabla");
 
-        // we currently only populate the dimension during writing out
-        // to avoid having to iterate all rows/cells in each add/remove of a row or cell
-        wb.write(new NullOutputStream());
+            row = sheet.createRow(4);
+            // Allowable column range for EXCEL2007 is (0..16383) or ('A'..'XDF')
+            cell = row.createCell(16383);
+            cell.setCellValue("blabla");
 
-        assertEquals("B2:XFD5", ((XSSFSheet)sheet).getCTWorksheet().getDimension().getRef());
+            // we currently only populate the dimension during writing out
+            // to avoid having to iterate all rows/cells in each add/remove of a row or cell
+            wb.write(NULL_OUTPUT_STREAM);
 
-        wb.close();
+            assertEquals("B2:XFD5", ((XSSFSheet) sheet).getCTWorksheet().getDimension().getRef());
+        }
     }
 
     @Test
     void bug61063() throws Exception {
-        try (Workbook wb = XSSFTestDataSamples.openSampleWorkbook("61063.xlsx")) {
+        try (Workbook wb = openSampleWorkbook("61063.xlsx")) {
 
             FormulaEvaluator eval = wb.getCreationHelper().createFormulaEvaluator();
             Sheet s = wb.getSheetAt(0);
@@ -3107,59 +3021,59 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
         final String initialFormula = "A1";
         final String expectedFormula = "#REF!"; // from ms excel
 
-        XSSFWorkbook wb = new XSSFWorkbook();
-        Sheet sheet = wb.createSheet("sheet1");
-        sheet.createRow(0).createCell(0).setCellValue(1); // A1 = 1
-
-        {
-            Cell c3 = sheet.createRow(2).createCell(2);
-            c3.setCellFormula(initialFormula); // C3 = =A1
-            FormulaEvaluator evaluator = wb.getCreationHelper().createFormulaEvaluator();
-            CellValue cellValue = evaluator.evaluate(c3);
-            assertEquals(1, cellValue.getNumberValue(), 0.0001);
-        }
+        try (XSSFWorkbook wb = new XSSFWorkbook()) {
+            Sheet sheet = wb.createSheet("sheet1");
+            sheet.createRow(0).createCell(0).setCellValue(1); // A1 = 1
+
+            {
+                Cell c3 = sheet.createRow(2).createCell(2);
+                c3.setCellFormula(initialFormula); // C3 = =A1
+                FormulaEvaluator evaluator = wb.getCreationHelper().createFormulaEvaluator();
+                CellValue cellValue = evaluator.evaluate(c3);
+                assertEquals(1, cellValue.getNumberValue(), 0.0001);
+            }
 
-        {
-            FormulaShifter formulaShifter = FormulaShifter.createForRowCopy(0, "sheet1", 2/*firstRowToShift*/, 2/*lastRowToShift*/
+            {
+                FormulaShifter formulaShifter = FormulaShifter.createForRowCopy(0, "sheet1", 2/*firstRowToShift*/, 2/*lastRowToShift*/
                     , -1/*step*/, SpreadsheetVersion.EXCEL2007);    // parameters 2, 2, -1 should mean : move row range [2-2] one level up
-            XSSFEvaluationWorkbook fpb = XSSFEvaluationWorkbook.create(wb);
-            Ptg[] ptgs = FormulaParser.parse(initialFormula, fpb, FormulaType.CELL, 0); // [A1]
-            formulaShifter.adjustFormula(ptgs, 0);    // adjusted to [A]
-            String shiftedFmla = FormulaRenderer.toFormulaString(fpb, ptgs);    //A
-            //System.out.println(String.format("initial formula : A1; expected formula value after shifting up : #REF!; actual formula value : %s", shiftedFmla));
-            assertEquals(expectedFormula, shiftedFmla,
-                "On copy we expect the formula to be adjusted, in this case it would point to row -1, which is an invalid REF");
-        }
+                XSSFEvaluationWorkbook fpb = XSSFEvaluationWorkbook.create(wb);
+                Ptg[] ptgs = FormulaParser.parse(initialFormula, fpb, FormulaType.CELL, 0); // [A1]
+                formulaShifter.adjustFormula(ptgs, 0);    // adjusted to [A]
+                String shiftedFmla = FormulaRenderer.toFormulaString(fpb, ptgs);    //A
+                //System.out.println(String.format("initial formula : A1; expected formula value after shifting up : #REF!; actual formula value : %s", shiftedFmla));
+                assertEquals(expectedFormula, shiftedFmla,
+                    "On copy we expect the formula to be adjusted, in this case it would point to row -1, which is an invalid REF");
+            }
 
-        {
-            FormulaShifter formulaShifter = FormulaShifter.createForRowShift(0, "sheet1", 2/*firstRowToShift*/, 2/*lastRowToShift*/
+            {
+                FormulaShifter formulaShifter = FormulaShifter.createForRowShift(0, "sheet1", 2/*firstRowToShift*/, 2/*lastRowToShift*/
                     , -1/*step*/, SpreadsheetVersion.EXCEL2007);    // parameters 2, 2, -1 should mean : move row range [2-2] one level up
-            XSSFEvaluationWorkbook fpb = XSSFEvaluationWorkbook.create(wb);
-            Ptg[] ptgs = FormulaParser.parse(initialFormula, fpb, FormulaType.CELL, 0); // [A1]
-            formulaShifter.adjustFormula(ptgs, 0);    // adjusted to [A]
-            String shiftedFmla = FormulaRenderer.toFormulaString(fpb, ptgs);    //A
-            //System.out.println(String.format("initial formula : A1; expected formula value after shifting up : #REF!; actual formula value : %s", shiftedFmla));
-            assertEquals(initialFormula, shiftedFmla,
-                "On move we expect the formula to stay the same, thus expecting the initial formula A1 here");
-        }
+                XSSFEvaluationWorkbook fpb = XSSFEvaluationWorkbook.create(wb);
+                Ptg[] ptgs = FormulaParser.parse(initialFormula, fpb, FormulaType.CELL, 0); // [A1]
+                formulaShifter.adjustFormula(ptgs, 0);    // adjusted to [A]
+                String shiftedFmla = FormulaRenderer.toFormulaString(fpb, ptgs);    //A
+                //System.out.println(String.format("initial formula : A1; expected formula value after shifting up : #REF!; actual formula value : %s", shiftedFmla));
+                assertEquals(initialFormula, shiftedFmla,
+                    "On move we expect the formula to stay the same, thus expecting the initial formula A1 here");
+            }
 
-        sheet.shiftRows(2, 2, -1);
-        {
-            Cell c2 = sheet.getRow(1).getCell(2);
-            assertNotNull(c2, "cell C2 needs to exist now");
-            assertEquals(CellType.FORMULA, c2.getCellType());
-            assertEquals(initialFormula, c2.getCellFormula());
-            FormulaEvaluator evaluator = wb.getCreationHelper().createFormulaEvaluator();
-            CellValue cellValue = evaluator.evaluate(c2);
-            assertEquals(1, cellValue.getNumberValue(), 0.0001);
-        }
+            sheet.shiftRows(2, 2, -1);
+            {
+                Cell c2 = sheet.getRow(1).getCell(2);
+                assertNotNull(c2, "cell C2 needs to exist now");
+                assertEquals(CellType.FORMULA, c2.getCellType());
+                assertEquals(initialFormula, c2.getCellFormula());
+                FormulaEvaluator evaluator = wb.getCreationHelper().createFormulaEvaluator();
+                CellValue cellValue = evaluator.evaluate(c2);
+                assertEquals(1, cellValue.getNumberValue(), 0.0001);
+            }
 
-        wb.close();
+        }
     }
 
     @Test
     void test61652() throws IOException {
-        try (Workbook wb = XSSFTestDataSamples.openSampleWorkbook("61652.xlsx")) {
+        try (Workbook wb = openSampleWorkbook("61652.xlsx")) {
             Sheet sheet = wb.getSheet("IRPPCalc");
             Row row = sheet.getRow(11);
             Cell cell = row.getCell(18);
@@ -3240,52 +3154,41 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
         }
     }
 
-    @Test
-    void test61905xlsx() throws IOException {
-        try (Workbook wb = new XSSFWorkbook()) {
-            checkActiveSheet(wb, XSSFITestDataProvider.instance);
-        }
-    }
-
-    @Test
-    void test61905xls() throws IOException {
-        try (Workbook wb = new HSSFWorkbook()) {
-            checkActiveSheet(wb, HSSFITestDataProvider.instance);
+    @ParameterizedTest
+    @ValueSource(booleans = { false, true })
+    void test61905(boolean xssf) throws IOException {
+        ITestDataProvider instance = xssf ?  XSSFITestDataProvider.instance : HSSFITestDataProvider.instance;
+        try (Workbook wb = instance.createWorkbook()) {
+            Sheet sheet = wb.createSheet("new sheet");
+            sheet.setActiveCell(new CellAddress("E11"));
+            assertEquals("E11", sheet.getActiveCell().formatAsString());
+
+            try (Workbook wbBack = instance.writeOutAndReadBack(wb)) {
+                sheet = wbBack.getSheetAt(0);
+                assertEquals("E11", sheet.getActiveCell().formatAsString());
+            }
         }
     }
 
-    private void checkActiveSheet(Workbook wb, ITestDataProvider instance) throws IOException {
-        Sheet sheet = wb.createSheet("new sheet");
-        sheet.setActiveCell(new CellAddress("E11"));
-        assertEquals("E11", sheet.getActiveCell().formatAsString());
-
-        Workbook wbBack = instance.writeOutAndReadBack(wb);
-        sheet = wbBack.getSheetAt(0);
-        assertEquals("E11", sheet.getActiveCell().formatAsString());
-        wbBack.close();
-    }
-
     @Test
     void testBug54084Unicode() throws IOException {
         // sample XLSX with the same text-contents as the text-file above
-        try (XSSFWorkbook wb = XSSFTestDataSamples.openSampleWorkbook("54084 - Greek - beyond BMP.xlsx")) {
+        try (XSSFWorkbook wb = openSampleWorkbook("54084 - Greek - beyond BMP.xlsx")) {
 
             verifyBug54084Unicode(wb);
 
             //XSSFTestDataSamples.writeOut(wb, "bug 54084 for manual review");
 
             // now write the file and read it back in
-            XSSFWorkbook wbWritten = XSSFTestDataSamples.writeOutAndReadBack(wb);
-            verifyBug54084Unicode(wbWritten);
+            try (XSSFWorkbook wbWritten = writeOutAndReadBack(wb)) {
+                verifyBug54084Unicode(wbWritten);
+            }
 
             // finally also write it out via the streaming interface and verify that we still can read it back in
-            SXSSFWorkbook swb = new SXSSFWorkbook(wb);
-            Workbook wbStreamingWritten = SXSSFITestDataProvider.instance.writeOutAndReadBack(swb);
-            verifyBug54084Unicode(wbStreamingWritten);
-
-            wbWritten.close();
-            swb.close();
-            wbStreamingWritten.close();
+            try (SXSSFWorkbook swb = new SXSSFWorkbook(wb);
+                 Workbook wbStreamingWritten = SXSSFITestDataProvider.instance.writeOutAndReadBack(swb)) {
+                verifyBug54084Unicode(wbStreamingWritten);
+            }
         }
     }
 
@@ -3309,29 +3212,15 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
     void bug63371() throws IOException {
         try (XSSFWorkbook wb = new XSSFWorkbook()) {
             XSSFSheet sheet = wb.createSheet();
-
             CellRangeAddress region = new CellRangeAddress(1, 1, 1, 2);
             assertEquals(0, sheet.addMergedRegion(region));
-            //System.out.println(String.format("%s: index=%d", "testAddMergedRegion", index));
-
-            final List<CellRangeAddress> ranges = sheet.getMergedRegions();
-            final int numMergedRegions = sheet.getNumMergedRegions();
-            final CTWorksheet ctSheet = sheet.getCTWorksheet();
-            final CTMergeCells ctMergeCells = ctSheet.getMergeCells();
-            final List<CTMergeCell> ctMergeCellList = ctMergeCells.getMergeCellList();
-            final long ctMergeCellCount = ctMergeCells.getCount();
-            final int ctMergeCellListSize = ctMergeCellList.size();
-
-        /*System.out.println(String.format("\ntestMergeRegions(%s)", "After adding first region"));
-        System.out.println(String.format("ranges.size=%d", ranges.size()));
-        System.out.println(String.format("numMergedRegions=%d", numMergedRegions));
-        System.out.println(String.format("ctMergeCellCount=%d", ctMergeCellCount));
-        System.out.println(String.format("ctMergeCellListSize=%d", ctMergeCellListSize));*/
 
-            assertEquals(1, ranges.size());
-            assertEquals(1, numMergedRegions);
-            assertEquals(1, ctMergeCellCount);
-            assertEquals(1, ctMergeCellListSize);
+            final CTMergeCells ctMergeCells = sheet.getCTWorksheet().getMergeCells();
+
+            assertEquals(1, sheet.getMergedRegions().size());
+            assertEquals(1, sheet.getNumMergedRegions());
+            assertEquals(1, ctMergeCells.getCount());
+            assertEquals(1, ctMergeCells.getMergeCellList().size());
 
         }
     }
@@ -3343,7 +3232,6 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
 
             CellRangeAddress region = new CellRangeAddress(1, 1, 1, 2);
             assertEquals(0, sheet.addMergedRegion(region));
-            //System.out.println(String.format("%s: index=%d", "testAddMergedRegion", index));
 
             List<CellRangeAddress> ranges = sheet.getMergedRegions();
             int numMergedRegions = sheet.getNumMergedRegions();
@@ -3353,12 +3241,6 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
             long ctMergeCellCount = ctMergeCells.getCount();
             int ctMergeCellListSize = ctMergeCellList.size();
 
-            /*System.out.println(String.format("\ntestMergeRegions(%s)", "After adding first region"));
-            System.out.println(String.format("ranges.size=%d", ranges.size()));
-            System.out.println(String.format("numMergedRegions=%d", numMergedRegions));
-            System.out.println(String.format("ctMergeCellCount=%d", ctMergeCellCount));
-            System.out.println(String.format("ctMergeCellListSize=%d", ctMergeCellListSize)); */
-
             assertEquals(1, ranges.size());
             assertEquals(1, numMergedRegions);
             assertEquals(1, ctMergeCellCount);
@@ -3366,7 +3248,6 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
 
             CellRangeAddress region2 = new CellRangeAddress(1, 2, 4, 6);
             assertEquals(1, sheet.addMergedRegion(region2));
-            //System.out.println(String.format("%s: index=%d", "testAddMergedRegion", index));
 
             ranges = sheet.getMergedRegions();
             numMergedRegions = sheet.getNumMergedRegions();
@@ -3376,12 +3257,6 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
             ctMergeCellCount = ctMergeCells.getCount();
             ctMergeCellListSize = ctMergeCellList.size();
 
-            /*System.out.println(String.format("\ntestMergeRegions(%s)", "After adding second region"));
-            System.out.println(String.format("ranges.size=%d", ranges.size()));
-            System.out.println(String.format("numMergedRegions=%d", numMergedRegions));
-            System.out.println(String.format("ctMergeCellCount=%d", ctMergeCellCount));
-            System.out.println(String.format("ctMergeCellListSize=%d", ctMergeCellListSize));*/
-
             assertEquals(2, ranges.size());
             assertEquals(2, numMergedRegions);
             assertEquals(2, ctMergeCellCount);
@@ -3420,7 +3295,7 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
 
     @Test
     void test58896WithFile() throws IOException {
-        try (Workbook wb = XSSFTestDataSamples.openSampleWorkbook("58896.xlsx")) {
+        try (Workbook wb = openSampleWorkbook("58896.xlsx")) {
             Sheet sheet = wb.getSheetAt(0);
             Instant start = now();
 
@@ -3455,7 +3330,7 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
             assertNull(((XSSFCell) cell).getCTCell().getV(),
                 "Element 'v' should not be set for formulas unless the value was calculated");
 
-            try (Workbook wbBack = XSSFTestDataSamples.writeOutAndReadBack(wb)) {
+            try (Workbook wbBack = writeOutAndReadBack(wb)) {
                 Cell cellBack = wbBack.getSheetAt(0).getRow(0).getCell(0);
                 assertNull(((XSSFCell) cellBack).getCTCell().getV(),
                     "Element 'v' should not be set for formulas unless the value was calculated");
@@ -3484,7 +3359,7 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
             row.createCell(1).setCellValue(5);
             row.createCell(2).setCellFormula("A1+B1");
 
-            try (Workbook wbBack = XSSFTestDataSamples.writeOutAndReadBack(wb)) {
+            try (Workbook wbBack = writeOutAndReadBack(wb)) {
                 Cell cellBack = wbBack.getSheetAt(0).getRow(0).getCell(2);
 
                 assertNull(((XSSFCell) cellBack).getCTCell().getV(),
@@ -3533,7 +3408,7 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
 
     @Test
     void testBug64508() throws IOException {
-        try (Workbook wb = XSSFTestDataSamples.openSampleWorkbook("64508.xlsx")) {
+        try (Workbook wb = openSampleWorkbook("64508.xlsx")) {
             int activeSheet = wb.getActiveSheetIndex();
             Sheet sheet1 = wb.getSheetAt(activeSheet);
             Row row = sheet1.getRow(1);
@@ -3547,7 +3422,7 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
     @Test
     void testBug64667() throws IOException {
         //test that an NPE isn't thrown on opening
-        try (Workbook wb = XSSFTestDataSamples.openSampleWorkbook("64667.xlsx")) {
+        try (Workbook wb = openSampleWorkbook("64667.xlsx")) {
             int activeSheet = wb.getActiveSheetIndex();
             assertEquals(0, activeSheet);
             assertNotNull(wb.getSheetAt(activeSheet));
@@ -3602,32 +3477,33 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
     }
 
     @Test
-    void test64986() {
-        XSSFWorkbook w = new XSSFWorkbook();
-        XSSFSheet s = w.createSheet();
-        XSSFRow r = s.createRow(0);
-        XSSFCell c = r.createCell(0);
-        c.setCellFormula("MATCH(\"VAL\",B1:B11,)");
+    void test64986() throws IOException {
+        try (XSSFWorkbook w = new XSSFWorkbook()) {
+            XSSFSheet s = w.createSheet();
+            XSSFRow r = s.createRow(0);
+            XSSFCell c = r.createCell(0);
+            c.setCellFormula("MATCH(\"VAL\",B1:B11,)");
 
-        FormulaEvaluator evaluator = w.getCreationHelper().createFormulaEvaluator();
-        CellValue value = evaluator.evaluate(c);
-        assertEquals(CellType.ERROR, value.getCellType());
-        assertEquals(ErrorEval.NA.getErrorCode(), value.getErrorValue());
+            FormulaEvaluator evaluator = w.getCreationHelper().createFormulaEvaluator();
+            CellValue value = evaluator.evaluate(c);
+            assertEquals(CellType.ERROR, value.getCellType());
+            assertEquals(ErrorEval.NA.getErrorCode(), value.getErrorValue());
 
-        // put a value in place so the match should find something
-        Cell val = r.createCell(1);
-        val.setCellValue("VAL");
+            // put a value in place so the match should find something
+            Cell val = r.createCell(1);
+            val.setCellValue("VAL");
 
-        // clear and check that now we find a match
-        evaluator.clearAllCachedResultValues();
-        value = evaluator.evaluate(c);
-        assertEquals(CellType.NUMERIC, value.getCellType());
-        assertEquals(1, value.getNumberValue(), 0.01);
+            // clear and check that now we find a match
+            evaluator.clearAllCachedResultValues();
+            value = evaluator.evaluate(c);
+            assertEquals(CellType.NUMERIC, value.getCellType());
+            assertEquals(1, value.getNumberValue(), 0.01);
+        }
     }
 
     @Test
     void test64750() throws IOException {
-        try (Workbook wb = XSSFTestDataSamples.openSampleWorkbook("64750.xlsx")) {
+        try (Workbook wb = openSampleWorkbook("64750.xlsx")) {
             Sheet sheet = wb.getSheet("Sheet1");
             assertEquals(1, sheet.getDataValidations().size());
         }
@@ -3635,7 +3511,7 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
 
     @Test
     void test64450() throws IOException {
-        try (Workbook wb = XSSFTestDataSamples.openSampleWorkbook("64450.xlsx")) {
+        try (Workbook wb = openSampleWorkbook("64450.xlsx")) {
             assertNotNull(wb);
         }
     }
@@ -3664,10 +3540,6 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
             cellLeft.setCellValue("L");
             cellLeft.setCellStyle(styleLeft);
 
-            /*try (OutputStream out = new FileOutputStream("/tmp/64494.xlsx")) {
-                wb.write(out);
-            }*/
-
             assertEquals(HorizontalAlignment.RIGHT, cellRight.getCellStyle().getAlignment());
             assertEquals(HorizontalAlignment.LEFT, cellLeft.getCellStyle().getAlignment());
         }
diff --git a/poi-ooxml/src/test/java/org/apache/poi/xssf/usermodel/TestXSSFPicture.java b/poi-ooxml/src/test/java/org/apache/poi/xssf/usermodel/TestXSSFPicture.java
index b544f916ac..064d2d83c1 100644
--- a/poi-ooxml/src/test/java/org/apache/poi/xssf/usermodel/TestXSSFPicture.java
+++ b/poi-ooxml/src/test/java/org/apache/poi/xssf/usermodel/TestXSSFPicture.java
@@ -20,6 +20,7 @@ package org.apache.poi.xssf.usermodel;
 import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertSame;
 
 import java.io.IOException;
 import java.util.List;
@@ -41,6 +42,7 @@ public final class TestXSSFPicture extends BaseTestPicture {
         super(XSSFITestDataProvider.instance);
     }
 
+    @Override
     protected Picture getPictureShape(Drawing<?> pat, int picIdx) {
         return (Picture)((XSSFDrawing)pat).getShapes().get(picIdx);
     }
@@ -73,7 +75,7 @@ public final class TestXSSFPicture extends BaseTestPicture {
 
             CTTwoCellAnchor ctShapeHolder = drawing.getCTDrawing().getTwoCellAnchorArray(0);
             // STEditAs.ABSOLUTE corresponds to ClientAnchor.DONT_MOVE_AND_RESIZE
-            assertEquals(STEditAs.ABSOLUTE, ctShapeHolder.getEditAs());
+            assertSame(STEditAs.ABSOLUTE, ctShapeHolder.getEditAs());
         }
     }
 
diff --git a/poi-ooxml/src/test/java/org/apache/poi/xssf/usermodel/TestXSSFVMLDrawing.java b/poi-ooxml/src/test/java/org/apache/poi/xssf/usermodel/TestXSSFVMLDrawing.java
index 3bd3012ef5..4ee8a83d3c 100644
--- a/poi-ooxml/src/test/java/org/apache/poi/xssf/usermodel/TestXSSFVMLDrawing.java
+++ b/poi-ooxml/src/test/java/org/apache/poi/xssf/usermodel/TestXSSFVMLDrawing.java
@@ -25,7 +25,6 @@ import static org.junit.jupiter.api.Assertions.assertSame;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.math.BigInteger;
@@ -45,6 +44,7 @@ import com.microsoft.schemas.vml.CTShapetype;
 import com.microsoft.schemas.vml.STExt;
 import com.microsoft.schemas.vml.STStrokeJoinStyle;
 import com.microsoft.schemas.vml.impl.CTShapetypeImpl;
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.POIDataSamples;
 import org.apache.xmlbeans.XmlException;
 import org.apache.xmlbeans.XmlObject;
@@ -62,8 +62,8 @@ class TestXSSFVMLDrawing {
         assertEquals(2, items.size());
         assertTrue(items.get(0) instanceof CTShapeLayout);
         CTShapeLayout layout = (CTShapeLayout)items.get(0);
-        assertEquals(STExt.EDIT, layout.getExt());
-        assertEquals(STExt.EDIT, layout.getIdmap().getExt());
+        assertSame(STExt.EDIT, layout.getExt());
+        assertSame(STExt.EDIT, layout.getIdmap().getExt());
         assertEquals("1", layout.getIdmap().getData());
 
         assertTrue(items.get(1) instanceof CTShapetype);
@@ -72,8 +72,8 @@ class TestXSSFVMLDrawing {
         assertEquals(202.0f, type.getSpt(), 0);
         assertEquals("m,l,21600r21600,l21600,xe", type.getPath2());
         assertEquals("_x0000_t202", type.getId());
-        assertEquals(STTrueFalse.T, type.getPathArray(0).getGradientshapeok());
-        assertEquals(STConnectType.RECT, type.getPathArray(0).getConnecttype());
+        assertSame(STTrueFalse.T, type.getPathArray(0).getGradientshapeok());
+        assertSame(STConnectType.RECT, type.getPathArray(0).getConnecttype());
 
         CTShape shape = vml.newCommentShape();
         items = vml.getItems();
@@ -82,16 +82,16 @@ class TestXSSFVMLDrawing {
         assertEquals("#_x0000_t202", shape.getType());
         assertEquals("position:absolute; visibility:hidden", shape.getStyle());
         assertEquals("#ffffe1", shape.getFillcolor());
-        assertEquals(STInsetMode.AUTO, shape.getInsetmode());
+        assertSame(STInsetMode.AUTO, shape.getInsetmode());
         assertEquals("#ffffe1", shape.getFillArray(0).getColor());
         CTShadow shadow = shape.getShadowArray(0);
-        assertEquals(STTrueFalse.T, shadow.getOn());
+        assertSame(STTrueFalse.T, shadow.getOn());
         assertEquals("black", shadow.getColor());
-        assertEquals(STTrueFalse.T, shadow.getObscured());
-        assertEquals(STConnectType.NONE, shape.getPathArray(0).getConnecttype());
+        assertSame(STTrueFalse.T, shadow.getObscured());
+        assertSame(STConnectType.NONE, shape.getPathArray(0).getConnecttype());
         assertEquals("mso-direction-alt:auto", shape.getTextboxArray(0).getStyle());
         CTClientData cldata = shape.getClientDataArray(0);
-        assertEquals(STObjectType.NOTE, cldata.getObjectType());
+        assertSame(STObjectType.NOTE, cldata.getObjectType());
         assertEquals(1, cldata.sizeOfMoveWithCellsArray());
         assertEquals(1, cldata.sizeOfSizeWithCellsArray());
         assertEquals("1, 15, 0, 2, 3, 15, 3, 16", cldata.getAnchorArray(0));
@@ -103,11 +103,11 @@ class TestXSSFVMLDrawing {
         assertEquals("[True]", cldata.getVisibleList().toString());
 
         //serialize and read again
-        ByteArrayOutputStream out = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream out = new UnsynchronizedByteArrayOutputStream();
         vml.write(out);
 
         XSSFVMLDrawing vml2 = new XSSFVMLDrawing();
-        vml2.read(new ByteArrayInputStream(out.toByteArray()));
+        vml2.read(out.toInputStream());
         List<XmlObject> items2 = vml2.getItems();
         assertEquals(3, items2.size());
         assertTrue(items2.get(0) instanceof CTShapeLayout);
@@ -208,6 +208,6 @@ class TestXSSFVMLDrawing {
         XmlObject xst = objs.get(0);
         assertTrue(xst instanceof CTShapetypeImpl);
         CTShapetype st = (CTShapetype)xst;
-        assertEquals(STStrokeJoinStyle.MITER, st.getStrokeArray(0).getJoinstyle());
+        assertSame(STStrokeJoinStyle.MITER, st.getStrokeArray(0).getJoinstyle());
     }
 }
\ No newline at end of file
diff --git a/poi-ooxml/src/test/java/org/apache/poi/xssf/usermodel/TestXSSFWorkbook.java b/poi-ooxml/src/test/java/org/apache/poi/xssf/usermodel/TestXSSFWorkbook.java
index 78563bc32e..ef17baa8e7 100644
--- a/poi-ooxml/src/test/java/org/apache/poi/xssf/usermodel/TestXSSFWorkbook.java
+++ b/poi-ooxml/src/test/java/org/apache/poi/xssf/usermodel/TestXSSFWorkbook.java
@@ -17,6 +17,11 @@
 
 package org.apache.poi.xssf.usermodel;
 
+import static org.apache.commons.io.output.NullOutputStream.NULL_OUTPUT_STREAM;
+import static org.apache.poi.hssf.HSSFTestDataSamples.openSampleFileStream;
+import static org.apache.poi.xssf.XSSFTestDataSamples.openSampleWorkbook;
+import static org.apache.poi.xssf.XSSFTestDataSamples.writeOut;
+import static org.apache.poi.xssf.XSSFTestDataSamples.writeOutAndReadBack;
 import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
@@ -27,12 +32,10 @@ import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.FileOutputStream;
 import java.io.IOException;
-import java.io.OutputStream;
 import java.nio.charset.StandardCharsets;
 import java.util.Date;
 import java.util.Iterator;
@@ -72,7 +75,6 @@ import org.apache.poi.util.TempFile;
 import org.apache.poi.xddf.usermodel.chart.XDDFBarChartData;
 import org.apache.poi.xddf.usermodel.chart.XDDFChartData;
 import org.apache.poi.xssf.XSSFITestDataProvider;
-import org.apache.poi.xssf.XSSFTestDataSamples;
 import org.apache.poi.xssf.model.StylesTable;
 import org.junit.jupiter.api.Test;
 import org.openxmlformats.schemas.spreadsheetml.x2006.main.CTCalcPr;
@@ -92,94 +94,87 @@ public final class  TestXSSFWorkbook extends BaseTestXWorkbook {
      */
     @Test
     void saveLoadNew() throws IOException, InvalidFormatException {
-        XSSFWorkbook wb1 = new XSSFWorkbook();
+        File file;
+        try (XSSFWorkbook wb1 = new XSSFWorkbook()) {
 
-        //check that the default date system is set to 1900
-        CTWorkbookPr pr = wb1.getCTWorkbook().getWorkbookPr();
-        assertNotNull(pr);
-        assertTrue(pr.isSetDate1904());
-        assertFalse(pr.getDate1904(), "XSSF must use the 1900 date system");
+            //check that the default date system is set to 1900
+            CTWorkbookPr pr = wb1.getCTWorkbook().getWorkbookPr();
+            assertNotNull(pr);
+            assertTrue(pr.isSetDate1904());
+            assertFalse(pr.getDate1904(), "XSSF must use the 1900 date system");
 
-        Sheet sheet1 = wb1.createSheet("sheet1");
-        Sheet sheet2 = wb1.createSheet("sheet2");
-        wb1.createSheet("sheet3");
+            Sheet sheet1 = wb1.createSheet("sheet1");
+            Sheet sheet2 = wb1.createSheet("sheet2");
+            wb1.createSheet("sheet3");
 
-        RichTextString rts = wb1.getCreationHelper().createRichTextString("hello world");
+            RichTextString rts = wb1.getCreationHelper().createRichTextString("hello world");
 
-        sheet1.createRow(0).createCell((short)0).setCellValue(1.2);
-        sheet1.createRow(1).createCell((short)0).setCellValue(rts);
-        sheet2.createRow(0);
+            sheet1.createRow(0).createCell((short) 0).setCellValue(1.2);
+            sheet1.createRow(1).createCell((short) 0).setCellValue(rts);
+            sheet2.createRow(0);
 
-        assertEquals(0, wb1.getSheetAt(0).getFirstRowNum());
-        assertEquals(1, wb1.getSheetAt(0).getLastRowNum());
-        assertEquals(0, wb1.getSheetAt(1).getFirstRowNum());
-        assertEquals(0, wb1.getSheetAt(1).getLastRowNum());
-        assertEquals(-1, wb1.getSheetAt(2).getFirstRowNum());
-        assertEquals(-1, wb1.getSheetAt(2).getLastRowNum());
+            assertEquals(0, wb1.getSheetAt(0).getFirstRowNum());
+            assertEquals(1, wb1.getSheetAt(0).getLastRowNum());
+            assertEquals(0, wb1.getSheetAt(1).getFirstRowNum());
+            assertEquals(0, wb1.getSheetAt(1).getLastRowNum());
+            assertEquals(-1, wb1.getSheetAt(2).getFirstRowNum());
+            assertEquals(-1, wb1.getSheetAt(2).getLastRowNum());
 
-        File file = TempFile.createTempFile("poi-", ".xlsx");
-        OutputStream out = new FileOutputStream(file);
-        wb1.write(out);
-        out.close();
+            file = writeOut(wb1, "poi-.xlsx");
+        }
 
         // Check the package contains what we'd expect it to
-        OPCPackage pkg = OPCPackage.open(file.toString());
-        PackagePart wbRelPart =
-            pkg.getPart(PackagingURIHelper.createPartName("/xl/_rels/workbook.xml.rels"));
-        assertNotNull(wbRelPart);
-        assertTrue(wbRelPart.isRelationshipPart());
-        assertEquals(ContentTypes.RELATIONSHIPS_PART, wbRelPart.getContentType());
-
-        PackagePart wbPart =
-            pkg.getPart(PackagingURIHelper.createPartName("/xl/workbook.xml"));
-        // Links to the three sheets, shared strings and styles
-        assertTrue(wbPart.hasRelationships());
-        assertEquals(5, wbPart.getRelationships().size());
-        wb1.close();
-
-        // Load back the XSSFWorkbook
-        @SuppressWarnings("resource")
-        XSSFWorkbook wb2 = new XSSFWorkbook(pkg);
-        assertEquals(3, wb2.getNumberOfSheets());
-        assertNotNull(wb2.getSheetAt(0));
-        assertNotNull(wb2.getSheetAt(1));
-        assertNotNull(wb2.getSheetAt(2));
-
-        assertNotNull(wb2.getSharedStringSource());
-        assertNotNull(wb2.getStylesSource());
-
-        assertEquals(0, wb2.getSheetAt(0).getFirstRowNum());
-        assertEquals(1, wb2.getSheetAt(0).getLastRowNum());
-        assertEquals(0, wb2.getSheetAt(1).getFirstRowNum());
-        assertEquals(0, wb2.getSheetAt(1).getLastRowNum());
-        assertEquals(-1, wb2.getSheetAt(2).getFirstRowNum());
-        assertEquals(-1, wb2.getSheetAt(2).getLastRowNum());
-
-        sheet1 = wb2.getSheetAt(0);
-        assertEquals(1.2, sheet1.getRow(0).getCell(0).getNumericCellValue(), 0.0001);
-        assertEquals("hello world", sheet1.getRow(1).getCell(0).getRichStringCellValue().getString());
-
-        pkg.close();
+        try (OPCPackage pkg = OPCPackage.open(file.toString())) {
+            PackagePart wbRelPart =
+                pkg.getPart(PackagingURIHelper.createPartName("/xl/_rels/workbook.xml.rels"));
+            assertNotNull(wbRelPart);
+            assertTrue(wbRelPart.isRelationshipPart());
+            assertEquals(ContentTypes.RELATIONSHIPS_PART, wbRelPart.getContentType());
+
+            PackagePart wbPart =
+                pkg.getPart(PackagingURIHelper.createPartName("/xl/workbook.xml"));
+            // Links to the three sheets, shared strings and styles
+            assertTrue(wbPart.hasRelationships());
+            assertEquals(5, wbPart.getRelationships().size());
+
+            // Load back the XSSFWorkbook
+            try (XSSFWorkbook wb2 = new XSSFWorkbook(pkg)) {
+                assertEquals(3, wb2.getNumberOfSheets());
+                assertNotNull(wb2.getSheetAt(0));
+                assertNotNull(wb2.getSheetAt(1));
+                assertNotNull(wb2.getSheetAt(2));
+
+                assertNotNull(wb2.getSharedStringSource());
+                assertNotNull(wb2.getStylesSource());
+
+                assertEquals(0, wb2.getSheetAt(0).getFirstRowNum());
+                assertEquals(1, wb2.getSheetAt(0).getLastRowNum());
+                assertEquals(0, wb2.getSheetAt(1).getFirstRowNum());
+                assertEquals(0, wb2.getSheetAt(1).getLastRowNum());
+                assertEquals(-1, wb2.getSheetAt(2).getFirstRowNum());
+                assertEquals(-1, wb2.getSheetAt(2).getLastRowNum());
+
+                Sheet sheet1 = wb2.getSheetAt(0);
+                assertEquals(1.2, sheet1.getRow(0).getCell(0).getNumericCellValue(), 0.0001);
+                assertEquals("hello world", sheet1.getRow(1).getCell(0).getRichStringCellValue().getString());
+            }
+        }
     }
 
     @Test
     void existing() throws Exception {
+        try (XSSFWorkbook workbook = openSampleWorkbook("Formatting.xlsx");
+             OPCPackage pkg = OPCPackage.open(openSampleFileStream("Formatting.xlsx"))) {
+            assertNotNull(workbook.getSharedStringSource());
+            assertNotNull(workbook.getStylesSource());
 
-        XSSFWorkbook workbook = XSSFTestDataSamples.openSampleWorkbook("Formatting.xlsx");
-        assertNotNull(workbook.getSharedStringSource());
-        assertNotNull(workbook.getStylesSource());
-
-        // And check a few low level bits too
-        OPCPackage pkg = OPCPackage.open(HSSFTestDataSamples.openSampleFileStream("Formatting.xlsx"));
-        PackagePart wbPart =
-            pkg.getPart(PackagingURIHelper.createPartName("/xl/workbook.xml"));
-
-        // Links to the three sheets, shared, styles and themes
-        assertTrue(wbPart.hasRelationships());
-        assertEquals(6, wbPart.getRelationships().size());
+            // And check a few low level bits too
+            PackagePart wbPart = pkg.getPart(PackagingURIHelper.createPartName("/xl/workbook.xml"));
 
-        pkg.close();
-        workbook.close();
+            // Links to the three sheets, shared, styles and themes
+            assertTrue(wbPart.hasRelationships());
+            assertEquals(6, wbPart.getRelationships().size());
+        }
     }
 
     @Test
@@ -230,7 +225,7 @@ public final class  TestXSSFWorkbook extends BaseTestXWorkbook {
 
     @Test
     void loadSave() throws IOException {
-        XSSFWorkbook workbook = XSSFTestDataSamples.openSampleWorkbook("Formatting.xlsx");
+        XSSFWorkbook workbook = openSampleWorkbook("Formatting.xlsx");
         assertEquals(3, workbook.getNumberOfSheets());
         assertEquals("dd/mm/yyyy", workbook.getSheetAt(0).getRow(1).getCell(0).getRichStringCellValue().getString());
         assertNotNull(workbook.getSharedStringSource());
@@ -238,7 +233,7 @@ public final class  TestXSSFWorkbook extends BaseTestXWorkbook {
 
         // Write out, and check
         // Load up again, check all still there
-        XSSFWorkbook wb2 = XSSFTestDataSamples.writeOutAndReadBack(workbook);
+        XSSFWorkbook wb2 = writeOutAndReadBack(workbook);
         assertEquals(3, wb2.getNumberOfSheets());
         assertNotNull(wb2.getSheetAt(0));
         assertNotNull(wb2.getSheetAt(1));
@@ -257,43 +252,41 @@ public final class  TestXSSFWorkbook extends BaseTestXWorkbook {
 
     @Test
     void styles() throws IOException {
-        XSSFWorkbook wb1 = XSSFTestDataSamples.openSampleWorkbook("Formatting.xlsx");
-
-        StylesTable ss = wb1.getStylesSource();
-        assertNotNull(ss);
-        StylesTable st = ss;
-
-        // Has 8 number formats
-        assertEquals(8, st.getNumDataFormats());
-        // Has 2 fonts
-        assertEquals(2, st.getFonts().size());
-        // Has 2 fills
-        assertEquals(2, st.getFills().size());
-        // Has 1 border
-        assertEquals(1, st.getBorders().size());
-
-        // Add two more styles
-        assertEquals(StylesTable.FIRST_CUSTOM_STYLE_ID + 8,
+        try (XSSFWorkbook wb1 = openSampleWorkbook("Formatting.xlsx")) {
+            StylesTable ss = wb1.getStylesSource();
+            assertNotNull(ss);
+            StylesTable st = ss;
+
+            // Has 8 number formats
+            assertEquals(8, st.getNumDataFormats());
+            // Has 2 fonts
+            assertEquals(2, st.getFonts().size());
+            // Has 2 fills
+            assertEquals(2, st.getFills().size());
+            // Has 1 border
+            assertEquals(1, st.getBorders().size());
+
+            // Add two more styles
+            assertEquals(StylesTable.FIRST_CUSTOM_STYLE_ID + 8,
                 st.putNumberFormat("testFORMAT"));
-        assertEquals(StylesTable.FIRST_CUSTOM_STYLE_ID + 8,
+            assertEquals(StylesTable.FIRST_CUSTOM_STYLE_ID + 8,
                 st.putNumberFormat("testFORMAT"));
-        assertEquals(StylesTable.FIRST_CUSTOM_STYLE_ID + 9,
+            assertEquals(StylesTable.FIRST_CUSTOM_STYLE_ID + 9,
                 st.putNumberFormat("testFORMAT2"));
-        assertEquals(10, st.getNumDataFormats());
-
+            assertEquals(10, st.getNumDataFormats());
 
-        // Save, load back in again, and check
-        XSSFWorkbook wb2 = XSSFTestDataSamples.writeOutAndReadBack(wb1);
-        wb1.close();
 
-        ss = wb2.getStylesSource();
-        assertNotNull(ss);
+            // Save, load back in again, and check
+            try (XSSFWorkbook wb2 = writeOutAndReadBack(wb1)) {
+                ss = wb2.getStylesSource();
+                assertNotNull(ss);
 
-        assertEquals(10, st.getNumDataFormats());
-        assertEquals(2, st.getFonts().size());
-        assertEquals(2, st.getFills().size());
-        assertEquals(1, st.getBorders().size());
-        wb2.close();
+                assertEquals(10, st.getNumDataFormats());
+                assertEquals(2, st.getFonts().size());
+                assertEquals(2, st.getFills().size());
+                assertEquals(1, st.getBorders().size());
+            }
+        }
     }
 
     @Test
@@ -305,7 +298,7 @@ public final class  TestXSSFWorkbook extends BaseTestXWorkbook {
             assertEquals(2, sheetId);
 
             //test file with gaps in the sheetId sequence
-            try (XSSFWorkbook wbBack = XSSFTestDataSamples.openSampleWorkbook("47089.xlsm")) {
+            try (XSSFWorkbook wbBack = openSampleWorkbook("47089.xlsm")) {
                 int lastSheetId = (int) wbBack.getSheetAt(wbBack.getNumberOfSheets() - 1).sheet.getSheetId();
                 sheetId = (int) wbBack.createSheet().sheet.getSheetId();
                 assertEquals(lastSheetId + 1, sheetId);
@@ -328,15 +321,15 @@ public final class  TestXSSFWorkbook extends BaseTestXWorkbook {
             assertNotNull(opcProps);
 
             opcProps.setTitleProperty("Testing Bugzilla #47460");
-            assertEquals("Apache POI", opcProps.getCreatorProperty().get());
+            assertEquals("Apache POI", opcProps.getCreatorProperty().orElse(""));
             opcProps.setCreatorProperty("poi-dev@poi.apache.org");
 
-            XSSFWorkbook wbBack = XSSFTestDataSamples.writeOutAndReadBack(workbook);
-            assertEquals("Apache POI", wbBack.getProperties().getExtendedProperties().getUnderlyingProperties().getApplication());
-            opcProps = wbBack.getProperties().getCoreProperties().getUnderlyingProperties();
-            assertEquals("Testing Bugzilla #47460", opcProps.getTitleProperty().get());
-            assertEquals("poi-dev@poi.apache.org", opcProps.getCreatorProperty().get());
-            wbBack.close();
+            try (XSSFWorkbook wbBack = writeOutAndReadBack(workbook)) {
+                assertEquals("Apache POI", wbBack.getProperties().getExtendedProperties().getUnderlyingProperties().getApplication());
+                opcProps = wbBack.getProperties().getCoreProperties().getUnderlyingProperties();
+                assertEquals("Testing Bugzilla #47460", opcProps.getTitleProperty().orElse(""));
+                assertEquals("poi-dev@poi.apache.org", opcProps.getCreatorProperty().orElse(""));
+            }
         }
     }
 
@@ -346,36 +339,36 @@ public final class  TestXSSFWorkbook extends BaseTestXWorkbook {
      */
     @Test
     void bug47668() throws Exception {
-        XSSFWorkbook workbook = XSSFTestDataSamples.openSampleWorkbook("47668.xlsx");
-        List<XSSFPictureData> allPictures = workbook.getAllPictures();
-        assertEquals(1, allPictures.size());
+        try (XSSFWorkbook workbook = openSampleWorkbook("47668.xlsx")) {
+            List<XSSFPictureData> allPictures = workbook.getAllPictures();
+            assertEquals(1, allPictures.size());
 
-        PackagePartName imagePartName = PackagingURIHelper
+            PackagePartName imagePartName = PackagingURIHelper
                 .createPartName("/xl/media/image1.jpeg");
-        PackagePart imagePart = workbook.getPackage().getPart(imagePartName);
-        assertNotNull(imagePart);
+            PackagePart imagePart = workbook.getPackage().getPart(imagePartName);
+            assertNotNull(imagePart);
 
-        for (XSSFPictureData pictureData : allPictures) {
-            PackagePart picturePart = pictureData.getPackagePart();
-            assertSame(imagePart, picturePart);
-        }
+            for (XSSFPictureData pictureData : allPictures) {
+                PackagePart picturePart = pictureData.getPackagePart();
+                assertSame(imagePart, picturePart);
+            }
 
-        XSSFSheet sheet0 = workbook.getSheetAt(0);
-        XSSFDrawing drawing0 = sheet0.createDrawingPatriarch();
-        XSSFPictureData pictureData0 = (XSSFPictureData) drawing0.getRelations().get(0);
-        byte[] data0 = pictureData0.getData();
-        CRC32 crc0 = new CRC32();
-        crc0.update(data0);
-
-        XSSFSheet sheet1 = workbook.getSheetAt(1);
-        XSSFDrawing drawing1 = sheet1.createDrawingPatriarch();
-        XSSFPictureData pictureData1 = (XSSFPictureData) drawing1.getRelations().get(0);
-        byte[] data1 = pictureData1.getData();
-        CRC32 crc1 = new CRC32();
-        crc1.update(data1);
-
-        assertEquals(crc0.getValue(), crc1.getValue());
-        workbook.close();
+            XSSFSheet sheet0 = workbook.getSheetAt(0);
+            XSSFDrawing drawing0 = sheet0.createDrawingPatriarch();
+            XSSFPictureData pictureData0 = (XSSFPictureData) drawing0.getRelations().get(0);
+            byte[] data0 = pictureData0.getData();
+            CRC32 crc0 = new CRC32();
+            crc0.update(data0);
+
+            XSSFSheet sheet1 = workbook.getSheetAt(1);
+            XSSFDrawing drawing1 = sheet1.createDrawingPatriarch();
+            XSSFPictureData pictureData1 = (XSSFPictureData) drawing1.getRelations().get(0);
+            byte[] data1 = pictureData1.getData();
+            CRC32 crc1 = new CRC32();
+            crc1.update(data1);
+
+            assertEquals(crc0.getValue(), crc1.getValue());
+        }
     }
 
     /**
@@ -384,27 +377,26 @@ public final class  TestXSSFWorkbook extends BaseTestXWorkbook {
     @SuppressWarnings("deprecation")
     @Test
     void bug47737() throws IOException {
-        XSSFWorkbook wb = XSSFTestDataSamples.openSampleWorkbook("47737.xlsx");
-        assertEquals(2, wb.getNumberOfNames());
-        assertNotNull(wb.getCalculationChain());
-
-        XSSFName nm0 = wb.getNameAt(0);
-        assertTrue(nm0.getCTName().isSetLocalSheetId());
-        assertEquals(0, nm0.getCTName().getLocalSheetId());
-
-        XSSFName nm1 = wb.getNameAt(1);
-        assertTrue(nm1.getCTName().isSetLocalSheetId());
-        assertEquals(1, nm1.getCTName().getLocalSheetId());
-
-        wb.removeSheetAt(0);
-        assertEquals(1, wb.getNumberOfNames());
-        XSSFName nm2 = wb.getNameAt(0);
-        assertTrue(nm2.getCTName().isSetLocalSheetId());
-        assertEquals(0, nm2.getCTName().getLocalSheetId());
-        //calculation chain is removed as well
-        assertNull(wb.getCalculationChain());
-        wb.close();
-
+        try (XSSFWorkbook wb = openSampleWorkbook("47737.xlsx")) {
+            assertEquals(2, wb.getNumberOfNames());
+            assertNotNull(wb.getCalculationChain());
+
+            XSSFName nm0 = wb.getNameAt(0);
+            assertTrue(nm0.getCTName().isSetLocalSheetId());
+            assertEquals(0, nm0.getCTName().getLocalSheetId());
+
+            XSSFName nm1 = wb.getNameAt(1);
+            assertTrue(nm1.getCTName().isSetLocalSheetId());
+            assertEquals(1, nm1.getCTName().getLocalSheetId());
+
+            wb.removeSheetAt(0);
+            assertEquals(1, wb.getNumberOfNames());
+            XSSFName nm2 = wb.getNameAt(0);
+            assertTrue(nm2.getCTName().isSetLocalSheetId());
+            assertEquals(0, nm2.getCTName().getLocalSheetId());
+            //calculation chain is removed as well
+            assertNull(wb.getCalculationChain());
+        }
     }
 
     /**
@@ -412,28 +404,28 @@ public final class  TestXSSFWorkbook extends BaseTestXWorkbook {
      */
     @Test
     void bug47813() throws IOException {
-        XSSFWorkbook wb1 = XSSFTestDataSamples.openSampleWorkbook("47813.xlsx");
-        assertEquals(3, wb1.getNumberOfSheets());
-        assertNotNull(wb1.getCalculationChain());
-
-        assertEquals("Numbers", wb1.getSheetName(0));
-        //the second sheet is of type 'chartsheet'
-        assertEquals("Chart", wb1.getSheetName(1));
-        assertTrue(wb1.getSheetAt(1) instanceof XSSFChartSheet);
-        assertEquals("SomeJunk", wb1.getSheetName(2));
-
-        wb1.removeSheetAt(2);
-        assertEquals(2, wb1.getNumberOfSheets());
-        assertNull(wb1.getCalculationChain());
-
-        XSSFWorkbook wb2 = XSSFTestDataSamples.writeOutAndReadBack(wb1);
-        assertEquals(2, wb2.getNumberOfSheets());
-        assertNull(wb2.getCalculationChain());
-
-        assertEquals("Numbers", wb2.getSheetName(0));
-        assertEquals("Chart", wb2.getSheetName(1));
-        wb2.close();
-        wb1.close();
+        try (XSSFWorkbook wb1 = openSampleWorkbook("47813.xlsx")) {
+            assertEquals(3, wb1.getNumberOfSheets());
+            assertNotNull(wb1.getCalculationChain());
+
+            assertEquals("Numbers", wb1.getSheetName(0));
+            //the second sheet is of type 'chartsheet'
+            assertEquals("Chart", wb1.getSheetName(1));
+            assertTrue(wb1.getSheetAt(1) instanceof XSSFChartSheet);
+            assertEquals("SomeJunk", wb1.getSheetName(2));
+
+            wb1.removeSheetAt(2);
+            assertEquals(2, wb1.getNumberOfSheets());
+            assertNull(wb1.getCalculationChain());
+
+            try (XSSFWorkbook wb2 = writeOutAndReadBack(wb1)) {
+                assertEquals(2, wb2.getNumberOfSheets());
+                assertNull(wb2.getCalculationChain());
+
+                assertEquals("Numbers", wb2.getSheetName(0));
+                assertEquals("Chart", wb2.getSheetName(1));
+            }
+        }
     }
 
     /**
@@ -461,14 +453,14 @@ public final class  TestXSSFWorkbook extends BaseTestXWorkbook {
             assertNull(wb1.getCellStyleAt((short) 2), "Shouldn't be able to get style at 2 that doesn't exist");
 
             // Save and reload
-            try (XSSFWorkbook nwb = XSSFTestDataSamples.writeOutAndReadBack(wb1)) {
+            try (XSSFWorkbook nwb = writeOutAndReadBack(wb1)) {
                 assertEquals(2, nwb.getNumCellStyles());
                 nwb.getCellStyleAt((short) 0);
                 nwb.getCellStyleAt((short) 1);
                 assertNull(nwb.getCellStyleAt((short) 2), "Shouldn't be able to get style at 2 that doesn't exist");
 
                 // Now with an existing file
-                try (XSSFWorkbook wb2 = XSSFTestDataSamples.openSampleWorkbook("sample.xlsx")) {
+                try (XSSFWorkbook wb2 = openSampleWorkbook("sample.xlsx")) {
                     assertEquals(3, wb2.getNumCellStyles());
                     wb2.getCellStyleAt((short) 0);
                     wb2.getCellStyleAt((short) 1);
@@ -501,7 +493,7 @@ public final class  TestXSSFWorkbook extends BaseTestXWorkbook {
             // calcMode="manual" is unset when forceFormulaRecalculation=true
             calcPr.setCalcMode(STCalcMode.MANUAL);
             wb.setForceFormulaRecalculation(true);
-            assertEquals(STCalcMode.AUTO, calcPr.getCalcMode());
+            assertSame(STCalcMode.AUTO, calcPr.getCalcMode());
             assertTrue(wb.getForceFormulaRecalculation());
 
             wb.setForceFormulaRecalculation(false);
@@ -514,26 +506,22 @@ public final class  TestXSSFWorkbook extends BaseTestXWorkbook {
 
     @Test
     void columnWidthPOI52233() throws Exception {
-        XSSFWorkbook workbook = new XSSFWorkbook();
-        XSSFSheet sheet = workbook.createSheet();
-        XSSFRow row = sheet.createRow(0);
-        XSSFCell cell = row.createCell(0);
-        cell.setCellValue("hello world");
-
-        sheet = workbook.createSheet();
-        sheet.setColumnWidth(4, 5000);
-        sheet.setColumnWidth(5, 5000);
+        try (XSSFWorkbook workbook = new XSSFWorkbook()) {
+            XSSFSheet sheet = workbook.createSheet();
+            XSSFRow row = sheet.createRow(0);
+            XSSFCell cell = row.createCell(0);
+            cell.setCellValue("hello world");
 
-        sheet.groupColumn((short) 4, (short) 5);
+            sheet = workbook.createSheet();
+            sheet.setColumnWidth(4, 5000);
+            sheet.setColumnWidth(5, 5000);
 
-        accessWorkbook(workbook);
+            sheet.groupColumn((short) 4, (short) 5);
 
-        try (ByteArrayOutputStream stream = new ByteArrayOutputStream()) {
-            workbook.write(stream);
+            accessWorkbook(workbook);
+            workbook.write(NULL_OUTPUT_STREAM);
+            accessWorkbook(workbook);
         }
-
-        accessWorkbook(workbook);
-        workbook.close();
     }
 
     private void accessWorkbook(XSSFWorkbook workbook) {
@@ -546,136 +534,128 @@ public final class  TestXSSFWorkbook extends BaseTestXWorkbook {
 
     @Test
     void bug48495() throws IOException {
-        Workbook wb = XSSFTestDataSamples.openSampleWorkbook("48495.xlsx");
+        try (Workbook wb = openSampleWorkbook("48495.xlsx")) {
+            assertSheetOrder(wb, "Sheet1");
+
+            Sheet sheet = wb.getSheetAt(0);
+            sheet.shiftRows(2, sheet.getLastRowNum(), 1, true, false);
+            Row newRow = sheet.getRow(2);
+            if (newRow == null) {
+                newRow = sheet.createRow(2);
+            }
+            newRow.createCell(0).setCellValue(" Another Header");
+            wb.cloneSheet(0);
 
-        assertSheetOrder(wb, "Sheet1");
+            assertSheetOrder(wb, "Sheet1", "Sheet1 (2)");
 
-        Sheet sheet = wb.getSheetAt(0);
-        sheet.shiftRows(2, sheet.getLastRowNum(), 1, true, false);
-        Row newRow = sheet.getRow(2);
-        if (newRow == null) {
-            newRow = sheet.createRow(2);
+            try (Workbook read = writeOutAndReadBack(wb)) {
+                assertNotNull(read);
+                assertSheetOrder(read, "Sheet1", "Sheet1 (2)");
+            }
         }
-        newRow.createCell(0).setCellValue(" Another Header");
-        wb.cloneSheet(0);
-
-        assertSheetOrder(wb, "Sheet1", "Sheet1 (2)");
-
-        //            FileOutputStream fileOut = new FileOutputStream("/tmp/bug48495.xlsx");
-//            try {
-//                wb.write(fileOut);
-//            } finally {
-//                fileOut.close();
-//            }
-
-        Workbook read = XSSFTestDataSamples.writeOutAndReadBack(wb);
-        assertNotNull(read);
-        assertSheetOrder(read, "Sheet1", "Sheet1 (2)");
-        read.close();
-        wb.close();
     }
 
     @Test
     void bug47090a() throws IOException {
-        Workbook workbook = XSSFTestDataSamples.openSampleWorkbook("47090.xlsx");
-        assertSheetOrder(workbook, "Sheet1", "Sheet2");
-        workbook.removeSheetAt(0);
-        assertSheetOrder(workbook, "Sheet2");
-        workbook.createSheet();
-        assertSheetOrder(workbook, "Sheet2", "Sheet1");
-        Workbook read = XSSFTestDataSamples.writeOutAndReadBack(workbook);
-        assertSheetOrder(read, "Sheet2", "Sheet1");
-        read.close();
-        workbook.close();
+        try (Workbook workbook = openSampleWorkbook("47090.xlsx")) {
+            assertSheetOrder(workbook, "Sheet1", "Sheet2");
+            workbook.removeSheetAt(0);
+            assertSheetOrder(workbook, "Sheet2");
+            workbook.createSheet();
+            assertSheetOrder(workbook, "Sheet2", "Sheet1");
+            try (Workbook read = writeOutAndReadBack(workbook)) {
+                assertSheetOrder(read, "Sheet2", "Sheet1");
+            }
+        }
     }
 
     @Test
     void bug47090b() throws IOException {
-        Workbook workbook = XSSFTestDataSamples.openSampleWorkbook("47090.xlsx");
-        assertSheetOrder(workbook, "Sheet1", "Sheet2");
-        workbook.removeSheetAt(1);
-        assertSheetOrder(workbook, "Sheet1");
-        workbook.createSheet();
-        assertSheetOrder(workbook, "Sheet1", "Sheet0");        // Sheet0 because it uses "Sheet" + sheets.size() as starting point!
-        Workbook read = XSSFTestDataSamples.writeOutAndReadBack(workbook);
-        assertSheetOrder(read, "Sheet1", "Sheet0");
-        read.close();
-        workbook.close();
+        try (Workbook workbook = openSampleWorkbook("47090.xlsx")) {
+            assertSheetOrder(workbook, "Sheet1", "Sheet2");
+            workbook.removeSheetAt(1);
+            assertSheetOrder(workbook, "Sheet1");
+            workbook.createSheet();
+            assertSheetOrder(workbook, "Sheet1", "Sheet0");        // Sheet0 because it uses "Sheet" + sheets.size() as starting point!
+            try (Workbook read = writeOutAndReadBack(workbook)) {
+                assertSheetOrder(read, "Sheet1", "Sheet0");
+            }
+        }
     }
 
     @Test
     void bug47090c() throws IOException {
-        Workbook workbook = XSSFTestDataSamples.openSampleWorkbook("47090.xlsx");
-        assertSheetOrder(workbook, "Sheet1", "Sheet2");
-        workbook.removeSheetAt(0);
-        assertSheetOrder(workbook, "Sheet2");
-        workbook.cloneSheet(0);
-        assertSheetOrder(workbook, "Sheet2", "Sheet2 (2)");
-        Workbook read = XSSFTestDataSamples.writeOutAndReadBack(workbook);
-        assertSheetOrder(read, "Sheet2", "Sheet2 (2)");
-        read.close();
-        workbook.close();
+        try (Workbook workbook = openSampleWorkbook("47090.xlsx")) {
+            assertSheetOrder(workbook, "Sheet1", "Sheet2");
+            workbook.removeSheetAt(0);
+            assertSheetOrder(workbook, "Sheet2");
+            workbook.cloneSheet(0);
+            assertSheetOrder(workbook, "Sheet2", "Sheet2 (2)");
+            try (Workbook read = writeOutAndReadBack(workbook)) {
+                assertSheetOrder(read, "Sheet2", "Sheet2 (2)");
+            }
+        }
     }
 
     @Test
     void bug47090d() throws IOException {
-        Workbook workbook = XSSFTestDataSamples.openSampleWorkbook("47090.xlsx");
-        assertSheetOrder(workbook, "Sheet1", "Sheet2");
-        workbook.createSheet();
-        assertSheetOrder(workbook, "Sheet1", "Sheet2", "Sheet0");
-        workbook.removeSheetAt(0);
-        assertSheetOrder(workbook, "Sheet2", "Sheet0");
-        workbook.createSheet();
-        assertSheetOrder(workbook, "Sheet2", "Sheet0", "Sheet1");
-        Workbook read = XSSFTestDataSamples.writeOutAndReadBack(workbook);
-        assertSheetOrder(read, "Sheet2", "Sheet0", "Sheet1");
-        read.close();
-        workbook.close();
+        try (Workbook workbook = openSampleWorkbook("47090.xlsx")) {
+            assertSheetOrder(workbook, "Sheet1", "Sheet2");
+            workbook.createSheet();
+            assertSheetOrder(workbook, "Sheet1", "Sheet2", "Sheet0");
+            workbook.removeSheetAt(0);
+            assertSheetOrder(workbook, "Sheet2", "Sheet0");
+            workbook.createSheet();
+            assertSheetOrder(workbook, "Sheet2", "Sheet0", "Sheet1");
+            try (Workbook read = writeOutAndReadBack(workbook)) {
+                assertSheetOrder(read, "Sheet2", "Sheet0", "Sheet1");
+            }
+        }
     }
 
     @Test
     void bug51158() throws IOException {
         // create a workbook
-        final XSSFWorkbook wb1 = new XSSFWorkbook();
-        XSSFSheet sheet = wb1.createSheet("Test Sheet");
-        XSSFRow row = sheet.createRow(2);
-        XSSFCell cell = row.createCell(3);
-        cell.setCellValue("test1");
+        try (XSSFWorkbook wb1 = new XSSFWorkbook()) {
+            XSSFSheet sheet = wb1.createSheet("Test Sheet");
+            XSSFRow row = sheet.createRow(2);
+            XSSFCell cell = row.createCell(3);
+            cell.setCellValue("test1");
 
-        //XSSFCreationHelper helper = workbook.getCreationHelper();
-        //cell.setHyperlink(helper.createHyperlink(0));
+            //XSSFCreationHelper helper = workbook.getCreationHelper();
+            //cell.setHyperlink(helper.createHyperlink(0));
 
-        XSSFComment comment = sheet.createDrawingPatriarch().createCellComment(new XSSFClientAnchor());
-        assertNotNull(comment);
-        comment.setString("some comment");
+            XSSFComment comment = sheet.createDrawingPatriarch().createCellComment(new XSSFClientAnchor());
+            assertNotNull(comment);
+            comment.setString("some comment");
 
 //        CellStyle cs = workbook.createCellStyle();
 //        cs.setShrinkToFit(false);
 //        row.createCell(0).setCellStyle(cs);
 
-        // write the first excel file
-        XSSFWorkbook wb2 = XSSFTestDataSamples.writeOutAndReadBack(wb1);
-        assertNotNull(wb2);
-        sheet = wb2.getSheetAt(0);
-        row = sheet.getRow(2);
-        assertEquals("test1", row.getCell(3).getStringCellValue());
-        assertNull(row.getCell(4));
-
-        // add a new cell to the sheet
-        cell = row.createCell(4);
-        cell.setCellValue("test2");
-
-        // write the second excel file
-        XSSFWorkbook wb3 = XSSFTestDataSamples.writeOutAndReadBack(wb2);
-        assertNotNull(wb3);
-        sheet = wb3.getSheetAt(0);
-        row = sheet.getRow(2);
-
-        assertEquals("test1", row.getCell(3).getStringCellValue());
-        assertEquals("test2", row.getCell(4).getStringCellValue());
-        wb3.close();
-        wb2.close();
-        wb1.close();
+            // write the first excel file
+            try (XSSFWorkbook wb2 = writeOutAndReadBack(wb1)) {
+                assertNotNull(wb2);
+                sheet = wb2.getSheetAt(0);
+                row = sheet.getRow(2);
+                assertEquals("test1", row.getCell(3).getStringCellValue());
+                assertNull(row.getCell(4));
+
+                // add a new cell to the sheet
+                cell = row.createCell(4);
+                cell.setCellValue("test2");
+
+                // write the second excel file
+                try (XSSFWorkbook wb3 = writeOutAndReadBack(wb2)) {
+                    assertNotNull(wb3);
+                    sheet = wb3.getSheetAt(0);
+                    row = sheet.getRow(2);
+
+                    assertEquals("test1", row.getCell(3).getStringCellValue());
+                    assertEquals("test2", row.getCell(4).getStringCellValue());
+                }
+            }
+        }
     }
 
     @Test
@@ -704,20 +684,20 @@ public final class  TestXSSFWorkbook extends BaseTestXWorkbook {
 
     @Test
     void bug60509() throws Exception {
-        XSSFWorkbook wb = XSSFTestDataSamples.openSampleWorkbook("60509.xlsx");
-        assertSheetOrder(wb, "Sheet1", "Sheet2", "Sheet3");
-        int sheetIndex = wb.getSheetIndex("Sheet1");
-        wb.setSheetName(sheetIndex, "Sheet1-Renamed");
-        Workbook read = XSSFTestDataSamples.writeOutAndReadBack(wb);
-        assertNotNull(read);
-        assertSheetOrder(read, "Sheet1-Renamed", "Sheet2", "Sheet3");
-        XSSFSheet sheet = (XSSFSheet) read.getSheet("Sheet1-Renamed");
-        XDDFChartData.Series series = sheet.getDrawingPatriarch().getCharts().get(0).getChartSeries().get(0).getSeries(0);
-        assertTrue(series instanceof XDDFBarChartData.Series, "should be a bar chart data series");
-        String formula = series.getCategoryData().getFormula();
-        assertTrue(formula.startsWith("'Sheet1-Renamed'!"), "should contain new sheet name");
-        read.close();
-        wb.close();
+        try (XSSFWorkbook wb = openSampleWorkbook("60509.xlsx")) {
+            assertSheetOrder(wb, "Sheet1", "Sheet2", "Sheet3");
+            int sheetIndex = wb.getSheetIndex("Sheet1");
+            wb.setSheetName(sheetIndex, "Sheet1-Renamed");
+            try (Workbook read = writeOutAndReadBack(wb)) {
+                assertNotNull(read);
+                assertSheetOrder(read, "Sheet1-Renamed", "Sheet2", "Sheet3");
+                XSSFSheet sheet = (XSSFSheet) read.getSheet("Sheet1-Renamed");
+                XDDFChartData.Series series = sheet.getDrawingPatriarch().getCharts().get(0).getChartSeries().get(0).getSeries(0);
+                assertTrue(series instanceof XDDFBarChartData.Series, "should be a bar chart data series");
+                String formula = series.getCategoryData().getFormula();
+                assertTrue(formula.startsWith("'Sheet1-Renamed'!"), "should contain new sheet name");
+            }
+        }
     }
 
     private static final int INDEX_NOT_FOUND = -1;
@@ -850,15 +830,14 @@ public final class  TestXSSFWorkbook extends BaseTestXWorkbook {
             assertEquals(idx2, wb.getFirstVisibleTab());
             assertEquals(idx3, wb.getActiveSheetIndex());
 
-            Workbook wbBack = XSSFTestDataSamples.writeOutAndReadBack(wb);
-
-            sheet2 = wbBack.getSheetAt(idx2);
-            assertNotNull(sheet2);
-            sheet3 = wbBack.getSheetAt(idx3);
-            assertNotNull(sheet3);
-            assertEquals(idx2, wb.getFirstVisibleTab());
-            assertEquals(idx3, wb.getActiveSheetIndex());
-            wbBack.close();
+            try (Workbook wbBack = writeOutAndReadBack(wb)) {
+                sheet2 = wbBack.getSheetAt(idx2);
+                assertNotNull(sheet2);
+                sheet3 = wbBack.getSheetAt(idx3);
+                assertNotNull(sheet3);
+                assertEquals(idx2, wb.getFirstVisibleTab());
+                assertEquals(idx3, wb.getActiveSheetIndex());
+            }
         }
     }
 
@@ -873,42 +852,39 @@ public final class  TestXSSFWorkbook extends BaseTestXWorkbook {
             allBytes[i] = (byte) (i - 128);
         }
 
-        XSSFWorkbook wb1 = new XSSFWorkbook();
-        wb1.createSheet();
-        wb1.setVBAProject(new ByteArrayInputStream(allBytes));
-        file = TempFile.createTempFile("poi-", ".xlsm");
-        OutputStream out = new FileOutputStream(file);
-        wb1.write(out);
-        out.close();
-        wb1.close();
+        try (XSSFWorkbook wb1 = new XSSFWorkbook()) {
+            wb1.createSheet();
+            wb1.setVBAProject(new ByteArrayInputStream(allBytes));
+            file = writeOut(wb1, "ooi-.xlsm");
+        }
 
         // Check the package contains what we'd expect it to
-        OPCPackage pkg = OPCPackage.open(file.toString());
-        PackagePart wbPart = pkg.getPart(PackagingURIHelper.createPartName("/xl/workbook.xml"));
-        assertTrue(wbPart.hasRelationships());
-        final PackageRelationshipCollection relationships = wbPart.getRelationships().getRelationships(XSSFRelation.VBA_MACROS.getRelation());
-        assertEquals(1, relationships.size());
-        PackageRelationship relationship = relationships.getRelationship(0);
-        assertNotNull(relationship);
-        assertEquals(XSSFRelation.VBA_MACROS.getDefaultFileName(), relationship.getTargetURI().toString());
-        PackagePart vbaPart = pkg.getPart(PackagingURIHelper.createPartName(XSSFRelation.VBA_MACROS.getDefaultFileName()));
-        assertNotNull(vbaPart);
-        assertFalse(vbaPart.isRelationshipPart());
-        assertEquals(XSSFRelation.VBA_MACROS.getContentType(), vbaPart.getContentType());
-        final byte[] fromFile = IOUtils.toByteArray(vbaPart.getInputStream());
-        assertArrayEquals(allBytes, fromFile);
-
-        // Load back the XSSFWorkbook just to check nothing explodes
-        @SuppressWarnings("resource")
-        XSSFWorkbook wb2 = new XSSFWorkbook(pkg);
-        assertEquals(1, wb2.getNumberOfSheets());
-        assertEquals(XSSFWorkbookType.XLSM, wb2.getWorkbookType());
-        pkg.close();
+        try (OPCPackage pkg = OPCPackage.open(file.toString())) {
+            PackagePart wbPart = pkg.getPart(PackagingURIHelper.createPartName("/xl/workbook.xml"));
+            assertTrue(wbPart.hasRelationships());
+            final PackageRelationshipCollection relationships = wbPart.getRelationships().getRelationships(XSSFRelation.VBA_MACROS.getRelation());
+            assertEquals(1, relationships.size());
+            PackageRelationship relationship = relationships.getRelationship(0);
+            assertNotNull(relationship);
+            assertEquals(XSSFRelation.VBA_MACROS.getDefaultFileName(), relationship.getTargetURI().toString());
+            PackagePart vbaPart = pkg.getPart(PackagingURIHelper.createPartName(XSSFRelation.VBA_MACROS.getDefaultFileName()));
+            assertNotNull(vbaPart);
+            assertFalse(vbaPart.isRelationshipPart());
+            assertEquals(XSSFRelation.VBA_MACROS.getContentType(), vbaPart.getContentType());
+            final byte[] fromFile = IOUtils.toByteArray(vbaPart.getInputStream());
+            assertArrayEquals(allBytes, fromFile);
+
+            // Load back the XSSFWorkbook just to check nothing explodes
+            try (XSSFWorkbook wb2 = new XSSFWorkbook(pkg)) {
+                assertEquals(1, wb2.getNumberOfSheets());
+                assertEquals(XSSFWorkbookType.XLSM, wb2.getWorkbookType());
+            }
+        }
     }
 
     @Test
     void testBug54399() throws IOException {
-        try (XSSFWorkbook workbook = XSSFTestDataSamples.openSampleWorkbook("54399.xlsx")) {
+        try (XSSFWorkbook workbook = openSampleWorkbook("54399.xlsx")) {
 
             for (int i = 0; i < workbook.getNumberOfSheets(); i++) {
                 String name = "SheetRenamed" + (i + 1);
@@ -920,14 +896,14 @@ public final class  TestXSSFWorkbook extends BaseTestXWorkbook {
     }
 
     /**
-     *  Iterator<XSSFSheet> XSSFWorkbook.iterator was committed in r700472 on 2008-09-30
-     *  and has been replaced with Iterator<Sheet> XSSFWorkbook.iterator
+     *  {@code Iterator<XSSFSheet> XSSFWorkbook.iterator} was committed in r700472 on 2008-09-30
+     *  and has been replaced with {@code Iterator<Sheet> XSSFWorkbook.iterator}
      *
      *  In order to make code for looping over sheets in workbooks standard, regardless
      *  of the type of workbook (HSSFWorkbook, XSSFWorkbook, SXSSFWorkbook), the previously
-     *  available Iterator<XSSFSheet> iterator and Iterator<XSSFSheet> sheetIterator
-     *  have been replaced with Iterator<Sheet>  {@link Sheet#iterator} and
-     *  Iterator<Sheet> {@link Workbook#sheetIterator}. This makes iterating over sheets in a workbook
+     *  available {@code Iterator<XSSFSheet> iterator} and {@code Iterator<XSSFSheet> sheetIterator}
+     *  have been replaced with {@code Iterator<Sheet>} {@link Sheet#iterator} and
+     *  {@code Iterator<Sheet>} {@link Workbook#sheetIterator}. This makes iterating over sheets in a workbook
      *  similar to iterating over rows in a sheet and cells in a row.
      *
      *  Note: this breaks backwards compatibility! Existing codebases will need to
@@ -1054,7 +1030,7 @@ public final class  TestXSSFWorkbook extends BaseTestXWorkbook {
 
             assertThrows(IOException.class, () -> {
                 try {
-                    XSSFTestDataSamples.writeOutAndReadBack(wb);
+                    writeOutAndReadBack(wb);
                 } catch (RuntimeException e) {
                     throw e.getCause();
                 }
@@ -1067,7 +1043,7 @@ public final class  TestXSSFWorkbook extends BaseTestXWorkbook {
      */
     @Test
     void getTable() throws IOException {
-       XSSFWorkbook wb = XSSFTestDataSamples.openSampleWorkbook("WithTable.xlsx");
+       XSSFWorkbook wb = openSampleWorkbook("WithTable.xlsx");
        XSSFTable table1 = wb.getTable("Tabella1");
        assertNotNull(table1, "Tabella1 was not found in workbook");
        assertEquals("Tabella1", table1.getName(), "Table name");
diff --git a/poi-ooxml/src/test/java/org/apache/poi/xssf/util/TestEvilUnclosedBRFixingInputStream.java b/poi-ooxml/src/test/java/org/apache/poi/xssf/util/TestEvilUnclosedBRFixingInputStream.java
index 77a7e8be08..ec2b4cc5e6 100644
--- a/poi-ooxml/src/test/java/org/apache/poi/xssf/util/TestEvilUnclosedBRFixingInputStream.java
+++ b/poi-ooxml/src/test/java/org/apache/poi/xssf/util/TestEvilUnclosedBRFixingInputStream.java
@@ -20,10 +20,10 @@ package org.apache.poi.xssf.util;
 import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 
 import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.nio.charset.StandardCharsets;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.util.IOUtils;
 import org.apache.poi.util.ReplacingInputStream;
 import org.junit.jupiter.api.Test;
@@ -68,23 +68,20 @@ public final class TestEvilUnclosedBRFixingInputStream {
         // Vary the buffer size, so that we can end up with the br in the
         //  overflow or only part in the buffer
         for(int i=5; i<orig.length; i++) {
-            EvilUnclosedBRFixingInputStream inp = new EvilUnclosedBRFixingInputStream(orig);
-
-            ByteArrayOutputStream bout = new ByteArrayOutputStream();
-            boolean going = true;
-            while(going) {
-                byte[] b = new byte[i];
-                int r = inp.read(b);
-                if(r > 0) {
+            try (EvilUnclosedBRFixingInputStream inp = new EvilUnclosedBRFixingInputStream(orig);
+                 UnsynchronizedByteArrayOutputStream bout = new UnsynchronizedByteArrayOutputStream()) {
+                for (;;) {
+                    byte[] b = new byte[i];
+                    int r = inp.read(b);
+                    if (r <= 0) {
+                        break;
+                    }
                     bout.write(b, 0, r);
-                } else {
-                    going = false;
                 }
-            }
 
-            byte[] result = bout.toByteArray();
-            assertArrayEquals(fixed, result);
-            inp.close();
+                byte[] result = bout.toByteArray();
+                assertArrayEquals(fixed, result);
+            }
         }
     }
 
diff --git a/poi-ooxml/src/test/java/org/apache/poi/xwpf/XWPFTestDataSamples.java b/poi-ooxml/src/test/java/org/apache/poi/xwpf/XWPFTestDataSamples.java
index b24d0bf46c..e38b5b1e2d 100644
--- a/poi-ooxml/src/test/java/org/apache/poi/xwpf/XWPFTestDataSamples.java
+++ b/poi-ooxml/src/test/java/org/apache/poi/xwpf/XWPFTestDataSamples.java
@@ -16,11 +16,10 @@
 ==================================================================== */
 package org.apache.poi.xwpf;
 
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.POIDataSamples;
 import org.apache.poi.util.IOUtils;
 import org.apache.poi.xwpf.usermodel.XWPFDocument;
@@ -33,10 +32,9 @@ public class XWPFTestDataSamples {
     }
 
     public static XWPFDocument writeOutAndReadBack(XWPFDocument doc) throws IOException {
-        ByteArrayOutputStream baos = new ByteArrayOutputStream(4096);
+        UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream(4096);
         doc.write(baos);
-        ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
-        return new XWPFDocument(bais);
+        return new XWPFDocument(baos.toInputStream());
     }
 
     public static byte[] getImage(String filename) throws IOException {
diff --git a/poi-ooxml/src/test/java/org/apache/poi/xwpf/usermodel/TestChangeTracking.java b/poi-ooxml/src/test/java/org/apache/poi/xwpf/usermodel/TestChangeTracking.java
index 39673c3bba..0b74bfa5f1 100644
--- a/poi-ooxml/src/test/java/org/apache/poi/xwpf/usermodel/TestChangeTracking.java
+++ b/poi-ooxml/src/test/java/org/apache/poi/xwpf/usermodel/TestChangeTracking.java
@@ -19,9 +19,9 @@ package org.apache.poi.xwpf.usermodel;
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
+import java.io.InputStream;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.xwpf.XWPFTestDataSamples;
 import org.junit.jupiter.api.Test;
 
@@ -58,14 +58,14 @@ class TestChangeTracking {
             r1.setText("Lorem ipsum dolor sit amet.");
             doc.setTrackRevisions(true);
 
-            ByteArrayOutputStream out = new ByteArrayOutputStream();
-            doc.write(out);
+            try (UnsynchronizedByteArrayOutputStream out = new UnsynchronizedByteArrayOutputStream()) {
+                doc.write(out);
 
-            ByteArrayInputStream inputStream = new ByteArrayInputStream(out.toByteArray());
-            XWPFDocument document = new XWPFDocument(inputStream);
-            inputStream.close();
-
-            assertTrue(document.isTrackRevisions());
+                try (InputStream inputStream = out.toInputStream()) {
+                    XWPFDocument document = new XWPFDocument(inputStream);
+                    assertTrue(document.isTrackRevisions());
+                }
+            }
         }
     }
 }
diff --git a/poi-ooxml/src/test/java/org/apache/poi/xwpf/usermodel/TestXWPFBugs.java b/poi-ooxml/src/test/java/org/apache/poi/xwpf/usermodel/TestXWPFBugs.java
index 2974c879dc..10c8fca9e7 100644
--- a/poi-ooxml/src/test/java/org/apache/poi/xwpf/usermodel/TestXWPFBugs.java
+++ b/poi-ooxml/src/test/java/org/apache/poi/xwpf/usermodel/TestXWPFBugs.java
@@ -16,6 +16,7 @@
 ==================================================================== */
 package org.apache.poi.xwpf.usermodel;
 
+import static org.apache.poi.xwpf.XWPFTestDataSamples.writeOutAndReadBack;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
@@ -23,8 +24,6 @@ import static org.junit.jupiter.api.Assertions.assertNull;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.math.BigInteger;
 import java.util.List;
@@ -170,15 +169,11 @@ class TestXWPFBugs {
     @Test
     void test59378() throws IOException {
         try (XWPFDocument doc = XWPFTestDataSamples.openSampleDocument("59378.docx")) {
-            ByteArrayOutputStream out = new ByteArrayOutputStream();
-            doc.write(out);
-            out.close();
-
-            try (XWPFDocument doc2 = new XWPFDocument(new ByteArrayInputStream(out.toByteArray()))) {
+            try (XWPFDocument doc2 = writeOutAndReadBack(doc)) {
                 assertNotNull(doc2);
             }
 
-            try (XWPFDocument docBack = XWPFTestDataSamples.writeOutAndReadBack(doc)) {
+            try (XWPFDocument docBack = writeOutAndReadBack(doc)) {
                 assertNotNull(docBack);
             }
         }
diff --git a/poi-ooxml/src/test/java/org/apache/poi/xwpf/usermodel/TestXWPFRun.java b/poi-ooxml/src/test/java/org/apache/poi/xwpf/usermodel/TestXWPFRun.java
index 856fcd9be3..dc614470ea 100644
--- a/poi-ooxml/src/test/java/org/apache/poi/xwpf/usermodel/TestXWPFRun.java
+++ b/poi-ooxml/src/test/java/org/apache/poi/xwpf/usermodel/TestXWPFRun.java
@@ -16,15 +16,17 @@
 ==================================================================== */
 package org.apache.poi.xwpf.usermodel;
 
+import static org.apache.poi.xwpf.XWPFTestDataSamples.openSampleDocument;
+import static org.apache.poi.xwpf.XWPFTestDataSamples.writeOutAndReadBack;
 import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertSame;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.math.BigInteger;
 import java.util.List;
@@ -296,7 +298,7 @@ class TestXWPFRun {
      */
     @Test
     void testExisting() throws IOException {
-        XWPFDocument doc = XWPFTestDataSamples.openSampleDocument("TestDocument.docx");
+        XWPFDocument doc = openSampleDocument("TestDocument.docx");
         XWPFParagraph p;
         XWPFRun run;
 
@@ -430,7 +432,7 @@ class TestXWPFRun {
 
     @Test
     void testPictureInHeader() throws IOException {
-        XWPFDocument sampleDoc = XWPFTestDataSamples.openSampleDocument("headerPic.docx");
+        XWPFDocument sampleDoc = openSampleDocument("headerPic.docx");
         XWPFHeaderFooterPolicy policy = sampleDoc.getHeaderFooterPolicy();
 
         XWPFHeader header = policy.getDefaultHeader();
@@ -486,7 +488,7 @@ class TestXWPFRun {
 
     @Test
     void testAddPicture() throws Exception {
-        XWPFDocument doc = XWPFTestDataSamples.openSampleDocument("TestDocument.docx");
+        XWPFDocument doc = openSampleDocument("TestDocument.docx");
         XWPFParagraph p = doc.getParagraphArray(2);
         XWPFRun r = p.getRuns().get(0);
 
@@ -498,7 +500,7 @@ class TestXWPFRun {
         assertEquals(1, doc.getAllPictures().size());
         assertEquals(1, r.getEmbeddedPictures().size());
 
-        XWPFDocument docBack = XWPFTestDataSamples.writeOutAndReadBack(doc);
+        XWPFDocument docBack = writeOutAndReadBack(doc);
         XWPFParagraph pBack = docBack.getParagraphArray(2);
         XWPFRun rBack = pBack.getRuns().get(0);
 
@@ -513,39 +515,39 @@ class TestXWPFRun {
      */
     @Test
     void testAddPictureInHeader() throws IOException, InvalidFormatException {
-        XWPFDocument doc = XWPFTestDataSamples.openSampleDocument("TestDocument.docx");
-        XWPFHeader hdr = doc.createHeader(HeaderFooterType.DEFAULT);
-        XWPFParagraph p = hdr.createParagraph();
-        XWPFRun r = p.createRun();
+        try (XWPFDocument doc = openSampleDocument("TestDocument.docx")) {
+            XWPFHeader hdr = doc.createHeader(HeaderFooterType.DEFAULT);
+            XWPFParagraph p = hdr.createParagraph();
+            XWPFRun r = p.createRun();
 
-        assertEquals(0, hdr.getAllPictures().size());
-        assertEquals(0, r.getEmbeddedPictures().size());
+            assertEquals(0, hdr.getAllPictures().size());
+            assertEquals(0, r.getEmbeddedPictures().size());
 
-        r.addPicture(new ByteArrayInputStream(new byte[0]), Document.PICTURE_TYPE_JPEG, "test.jpg", 21, 32);
+            r.addPicture(new ByteArrayInputStream(new byte[0]), Document.PICTURE_TYPE_JPEG, "test.jpg", 21, 32);
 
-        assertEquals(1, hdr.getAllPictures().size());
-        assertEquals(1, r.getEmbeddedPictures().size());
+            assertEquals(1, hdr.getAllPictures().size());
+            assertEquals(1, r.getEmbeddedPictures().size());
 
-        XWPFPicture pic = r.getEmbeddedPictures().get(0);
-        CTPicture ctPic = pic.getCTPicture();
-        CTBlipFillProperties ctBlipFill = ctPic.getBlipFill();
+            XWPFPicture pic = r.getEmbeddedPictures().get(0);
+            CTPicture ctPic = pic.getCTPicture();
+            CTBlipFillProperties ctBlipFill = ctPic.getBlipFill();
 
-        assertNotNull(ctBlipFill);
+            assertNotNull(ctBlipFill);
 
-        CTBlip ctBlip = ctBlipFill.getBlip();
+            CTBlip ctBlip = ctBlipFill.getBlip();
 
-        assertNotNull(ctBlip);
-        assertEquals("rId1", ctBlip.getEmbed());
+            assertNotNull(ctBlip);
+            assertEquals("rId1", ctBlip.getEmbed());
 
-        XWPFDocument docBack = XWPFTestDataSamples.writeOutAndReadBack(doc);
-        XWPFHeader hdrBack = docBack.getHeaderArray(0);
-        XWPFParagraph pBack = hdrBack.getParagraphArray(0);
-        XWPFRun rBack = pBack.getRuns().get(0);
+            try (XWPFDocument docBack = writeOutAndReadBack(doc)) {
+                XWPFHeader hdrBack = docBack.getHeaderArray(0);
+                XWPFParagraph pBack = hdrBack.getParagraphArray(0);
+                XWPFRun rBack = pBack.getRuns().get(0);
 
-        assertEquals(1, hdrBack.getAllPictures().size());
-        assertEquals(1, rBack.getEmbeddedPictures().size());
-        docBack.close();
-        doc.close();
+                assertEquals(1, hdrBack.getAllPictures().size());
+                assertEquals(1, rBack.getEmbeddedPictures().size());
+            }
+        }
     }
 
     /**
@@ -554,7 +556,7 @@ class TestXWPFRun {
      */
     @Test
     void testSetFontFamily_52288() throws IOException {
-        try (XWPFDocument doc = XWPFTestDataSamples.openSampleDocument("52288.docx")) {
+        try (XWPFDocument doc = openSampleDocument("52288.docx")) {
             doc.getParagraphs().stream()
                 .flatMap(p -> p.getRuns().stream())
                 .filter(p -> p != null && p.getText(0) != null)
@@ -565,157 +567,148 @@ class TestXWPFRun {
     @Test
     void testBug55476() throws IOException, InvalidFormatException {
         byte[] image = XWPFTestDataSamples.getImage("abstract1.jpg");
-        XWPFDocument document = new XWPFDocument();
+        try (XWPFDocument document = new XWPFDocument()) {
 
-        document.createParagraph().createRun().addPicture(
+            document.createParagraph().createRun().addPicture(
                 new ByteArrayInputStream(image), Document.PICTURE_TYPE_JPEG, "test.jpg", Units.toEMU(300), Units.toEMU(100));
 
-        XWPFDocument docBack = XWPFTestDataSamples.writeOutAndReadBack(document);
-        List<XWPFPicture> pictures = docBack.getParagraphArray(0).getRuns().get(0).getEmbeddedPictures();
-        assertEquals(1, pictures.size());
-        docBack.close();
-
-        /*OutputStream stream = new FileOutputStream("c:\\temp\\55476.docx");
-        try {
-            document.write(stream);
-        } finally {
-            stream.close();
-        }*/
-
-        document.close();
+            try (XWPFDocument docBack = writeOutAndReadBack(document)) {
+                List<XWPFPicture> pictures = docBack.getParagraphArray(0).getRuns().get(0).getEmbeddedPictures();
+                assertEquals(1, pictures.size());
+            }
+        }
     }
 
     @Test
     void testBug58922() throws IOException {
-        XWPFDocument document = new XWPFDocument();
-
-        final XWPFRun run = document.createParagraph().createRun();
+        try (XWPFDocument document = new XWPFDocument()) {
 
+            final XWPFRun run = document.createParagraph().createRun();
 
-        assertEquals(-1, run.getFontSize());
 
-        run.setFontSize(10);
-        assertEquals(10, run.getFontSize());
+            assertEquals(-1, run.getFontSize());
 
-        run.setFontSize(Short.MAX_VALUE-1);
-        assertEquals(Short.MAX_VALUE-1, run.getFontSize());
+            run.setFontSize(10);
+            assertEquals(10, run.getFontSize());
 
-        run.setFontSize(Short.MAX_VALUE);
-        assertEquals(Short.MAX_VALUE, run.getFontSize());
+            run.setFontSize(Short.MAX_VALUE - 1);
+            assertEquals(Short.MAX_VALUE - 1, run.getFontSize());
 
-        run.setFontSize(Short.MAX_VALUE+1);
-        assertEquals(Short.MAX_VALUE+1, run.getFontSize());
+            run.setFontSize(Short.MAX_VALUE);
+            assertEquals(Short.MAX_VALUE, run.getFontSize());
 
-        run.setFontSize(Integer.MAX_VALUE-1);
-        assertEquals(Integer.MAX_VALUE-1, run.getFontSize());
+            run.setFontSize(Short.MAX_VALUE + 1);
+            assertEquals(Short.MAX_VALUE + 1, run.getFontSize());
 
-        run.setFontSize(Integer.MAX_VALUE);
-        assertEquals(Integer.MAX_VALUE, run.getFontSize());
+            run.setFontSize(Integer.MAX_VALUE - 1);
+            assertEquals(Integer.MAX_VALUE - 1, run.getFontSize());
 
-        run.setFontSize(-1);
-        assertEquals(-1, run.getFontSize());
+            run.setFontSize(Integer.MAX_VALUE);
+            assertEquals(Integer.MAX_VALUE, run.getFontSize());
 
+            run.setFontSize(-1);
+            assertEquals(-1, run.getFontSize());
 
-        assertEquals(-1, run.getTextPosition());
 
-        run.setTextPosition(10);
-        assertEquals(10, run.getTextPosition());
+            assertEquals(-1, run.getTextPosition());
 
-        run.setTextPosition(Short.MAX_VALUE-1);
-        assertEquals(Short.MAX_VALUE-1, run.getTextPosition());
+            run.setTextPosition(10);
+            assertEquals(10, run.getTextPosition());
 
-        run.setTextPosition(Short.MAX_VALUE);
-        assertEquals(Short.MAX_VALUE, run.getTextPosition());
+            run.setTextPosition(Short.MAX_VALUE - 1);
+            assertEquals(Short.MAX_VALUE - 1, run.getTextPosition());
 
-        run.setTextPosition(Short.MAX_VALUE+1);
-        assertEquals(Short.MAX_VALUE+1, run.getTextPosition());
+            run.setTextPosition(Short.MAX_VALUE);
+            assertEquals(Short.MAX_VALUE, run.getTextPosition());
 
-        run.setTextPosition(Short.MAX_VALUE+1);
-        assertEquals(Short.MAX_VALUE+1, run.getTextPosition());
+            run.setTextPosition(Short.MAX_VALUE + 1);
+            assertEquals(Short.MAX_VALUE + 1, run.getTextPosition());
 
-        run.setTextPosition(Integer.MAX_VALUE-1);
-        assertEquals(Integer.MAX_VALUE-1, run.getTextPosition());
+            run.setTextPosition(Short.MAX_VALUE + 1);
+            assertEquals(Short.MAX_VALUE + 1, run.getTextPosition());
 
-        run.setTextPosition(Integer.MAX_VALUE);
-        assertEquals(Integer.MAX_VALUE, run.getTextPosition());
+            run.setTextPosition(Integer.MAX_VALUE - 1);
+            assertEquals(Integer.MAX_VALUE - 1, run.getTextPosition());
 
-        run.setTextPosition(-1);
-        assertEquals(-1, run.getTextPosition());
+            run.setTextPosition(Integer.MAX_VALUE);
+            assertEquals(Integer.MAX_VALUE, run.getTextPosition());
 
-        document.close();
+            run.setTextPosition(-1);
+            assertEquals(-1, run.getTextPosition());
+        }
     }
 
     @Test
-    void testSetters() {
-        XWPFDocument document = new XWPFDocument();
-        final XWPFRun run = document.createParagraph().createRun();
-
-        // at least trigger some of the setters to ensure classes are included in
-        // the poi-ooxml-lite
-        run.setBold(true);
-        run.setCapitalized(true);
-        run.setCharacterSpacing(2);
-        assertEquals(2, run.getCharacterSpacing());
-        run.setColor("000000");
-        run.setDoubleStrikethrough(true);
-        run.setEmbossed(true);
-        run.setFontFamily("Calibri");
-        assertEquals("Calibri", run.getFontFamily());
-        run.setFontSize(10);
-        assertEquals(10, run.getFontSize());
-        run.setImprinted(true);
-        run.setItalic(true);
+    void testSetters() throws IOException {
+        try (XWPFDocument document = new XWPFDocument()) {
+            final XWPFRun run = document.createParagraph().createRun();
+
+            // at least trigger some of the setters to ensure classes are included in
+            // the poi-ooxml-lite
+            run.setBold(true);
+            run.setCapitalized(true);
+            run.setCharacterSpacing(2);
+            assertEquals(2, run.getCharacterSpacing());
+            run.setColor("000000");
+            run.setDoubleStrikethrough(true);
+            run.setEmbossed(true);
+            run.setFontFamily("Calibri");
+            assertEquals("Calibri", run.getFontFamily());
+            run.setFontSize(10);
+            assertEquals(10, run.getFontSize());
+            run.setImprinted(true);
+            run.setItalic(true);
+        }
     }
 
     @Test
     void testSetGetTextScale() throws IOException {
-        XWPFDocument document = new XWPFDocument();
-        final XWPFRun run = document.createParagraph().createRun();
-        assertEquals(100, run.getTextScale());
-        run.setTextScale(200);
-        assertEquals(200, run.getTextScale());
-        document.close();
+        try (XWPFDocument document = new XWPFDocument()) {
+            final XWPFRun run = document.createParagraph().createRun();
+            assertEquals(100, run.getTextScale());
+            run.setTextScale(200);
+            assertEquals(200, run.getTextScale());
+        }
     }
 
     @Test
     void testSetGetTextHighlightColor() throws IOException {
-        XWPFDocument document = new XWPFDocument();
-        final XWPFRun run = document.createParagraph().createRun();
-        assertEquals(STHighlightColor.NONE, run.getTextHightlightColor());
-        assertFalse(run.isHighlighted());
-        run.setTextHighlightColor("darkGreen"); // See 17.18.40 ST_HighlightColor (Text Highlight Colors)
-        assertEquals(STHighlightColor.DARK_GREEN, run.getTextHightlightColor());
-        assertTrue(run.isHighlighted());
-        run.setTextHighlightColor("none");
-        assertFalse(run.isHighlighted());
-
-        document.close();
+        try (XWPFDocument document = new XWPFDocument()) {
+            final XWPFRun run = document.createParagraph().createRun();
+            assertSame(STHighlightColor.NONE, run.getTextHightlightColor());
+            assertFalse(run.isHighlighted());
+            run.setTextHighlightColor("darkGreen"); // See 17.18.40 ST_HighlightColor (Text Highlight Colors)
+            assertSame(STHighlightColor.DARK_GREEN, run.getTextHightlightColor());
+            assertTrue(run.isHighlighted());
+            run.setTextHighlightColor("none");
+            assertFalse(run.isHighlighted());
+        }
     }
 
     @Test
     void testSetGetVanish() throws IOException {
-        XWPFDocument document = new XWPFDocument();
-        final XWPFRun run = document.createParagraph().createRun();
-        assertFalse(run.isVanish());
-        run.setVanish(true);
-        assertTrue(run.isVanish());
-        run.setVanish(false);
-        assertFalse(run.isVanish());
-        document.close();
+        try (XWPFDocument document = new XWPFDocument()) {
+            final XWPFRun run = document.createParagraph().createRun();
+            assertFalse(run.isVanish());
+            run.setVanish(true);
+            assertTrue(run.isVanish());
+            run.setVanish(false);
+            assertFalse(run.isVanish());
+        }
     }
 
     @Test
     void testSetGetVerticalAlignment() throws IOException {
-        XWPFDocument document = new XWPFDocument();
-        XWPFRun run = document.createParagraph().createRun();
-        assertEquals(STVerticalAlignRun.BASELINE, run.getVerticalAlignment());
-        // Reset to a fresh run so we test case of run not having vertical alignment at all
-        run = document.createParagraph().createRun();
-        run.setVerticalAlignment("subscript");
-        assertEquals(STVerticalAlignRun.SUBSCRIPT, run.getVerticalAlignment());
-        run.setVerticalAlignment("superscript");
-        assertEquals(STVerticalAlignRun.SUPERSCRIPT, run.getVerticalAlignment());
-        document.close();
+        try (XWPFDocument document = new XWPFDocument()) {
+            XWPFRun run = document.createParagraph().createRun();
+            assertSame(STVerticalAlignRun.BASELINE, run.getVerticalAlignment());
+            // Reset to a fresh run so we test case of run not having vertical alignment at all
+            run = document.createParagraph().createRun();
+            run.setVerticalAlignment("subscript");
+            assertSame(STVerticalAlignRun.SUBSCRIPT, run.getVerticalAlignment());
+            run.setVerticalAlignment("superscript");
+            assertSame(STVerticalAlignRun.SUPERSCRIPT, run.getVerticalAlignment());
+        }
     }
 
     @Test
@@ -726,82 +719,81 @@ class TestXWPFRun {
         XWPFRun run = new XWPFRun(ctRun, irb);
 
         run.setSubscript(VerticalAlign.BASELINE);
-        assertEquals(STVerticalAlignRun.BASELINE, rpr.getVertAlignArray(0).getVal());
+        assertSame(STVerticalAlignRun.BASELINE, rpr.getVertAlignArray(0).getVal());
     }
 
     @Test
     void testSetGetEmphasisMark() throws IOException {
-        XWPFDocument document = new XWPFDocument();
-        XWPFRun run = document.createParagraph().createRun();
-        assertEquals(STEm.NONE, run.getEmphasisMark());
-        // Reset to a fresh run so we test case of run not having property at all
-        run = document.createParagraph().createRun();
-        run.setEmphasisMark("dot");
-        assertEquals(STEm.DOT, run.getEmphasisMark());
-        document.close();
+        try (XWPFDocument document = new XWPFDocument()) {
+            XWPFRun run = document.createParagraph().createRun();
+            assertSame(STEm.NONE, run.getEmphasisMark());
+            // Reset to a fresh run so we test case of run not having property at all
+            run = document.createParagraph().createRun();
+            run.setEmphasisMark("dot");
+            assertSame(STEm.DOT, run.getEmphasisMark());
+        }
     }
 
     @Test
     void testSetGetUnderlineColor() throws IOException {
-        XWPFDocument document = new XWPFDocument();
-        XWPFRun run = document.createParagraph().createRun();
-        assertEquals("auto", run.getUnderlineColor());
-        // Reset to a fresh run so we test case of run not having property at all
-        run = document.createParagraph().createRun();
-        String colorRgb = "C0F1a2";
-        run.setUnderlineColor(colorRgb);
-        assertEquals(colorRgb.toUpperCase(LocaleUtil.getUserLocale()), run.getUnderlineColor());
-        run.setUnderlineColor("auto");
-        assertEquals("auto", run.getUnderlineColor());
-        document.close();
+        try (XWPFDocument document = new XWPFDocument()) {
+            XWPFRun run = document.createParagraph().createRun();
+            assertEquals("auto", run.getUnderlineColor());
+            // Reset to a fresh run so we test case of run not having property at all
+            run = document.createParagraph().createRun();
+            String colorRgb = "C0F1a2";
+            run.setUnderlineColor(colorRgb);
+            assertEquals(colorRgb.toUpperCase(LocaleUtil.getUserLocale()), run.getUnderlineColor());
+            run.setUnderlineColor("auto");
+            assertEquals("auto", run.getUnderlineColor());
+        }
     }
 
     @Test
     void testSetGetUnderlineThemeColor() throws IOException {
-        XWPFDocument document = new XWPFDocument();
-        XWPFRun run = document.createParagraph().createRun();
-        assertEquals(STThemeColor.NONE, run.getUnderlineThemeColor());
-        // Reset to a fresh run so we test case of run not having property at all
-        run = document.createParagraph().createRun();
-        String colorName = "accent4";
-        run.setUnderlineThemeColor(colorName);
-        assertEquals(STThemeColor.Enum.forString(colorName), run.getUnderlineThemeColor());
-        run.setUnderlineThemeColor("none");
-        assertEquals(STThemeColor.NONE, run.getUnderlineThemeColor());
-        document.close();
+        try (XWPFDocument document = new XWPFDocument()) {
+            XWPFRun run = document.createParagraph().createRun();
+            assertSame(STThemeColor.NONE, run.getUnderlineThemeColor());
+            // Reset to a fresh run so we test case of run not having property at all
+            run = document.createParagraph().createRun();
+            String colorName = "accent4";
+            run.setUnderlineThemeColor(colorName);
+            assertSame(STThemeColor.Enum.forString(colorName), run.getUnderlineThemeColor());
+            run.setUnderlineThemeColor("none");
+            assertSame(STThemeColor.NONE, run.getUnderlineThemeColor());
+        }
     }
 
 
     @Test
     void testSetStyleId() throws IOException {
-        XWPFDocument document = XWPFTestDataSamples.openSampleDocument("SampleDoc.docx");
-        final XWPFRun run = document.createParagraph().createRun();
-
-        String styleId = "bolditalic";
-        run.setStyle(styleId);
-        String candStyleId = run.getCTR().getRPr().getRStyleArray(0).getVal();
-        assertNotNull( candStyleId, "Expected to find a run style ID" );
-        assertEquals(styleId, candStyleId);
+        try (XWPFDocument document = openSampleDocument("SampleDoc.docx")) {
+            final XWPFRun run = document.createParagraph().createRun();
 
-        assertEquals(styleId, run.getStyle());
+            String styleId = "bolditalic";
+            run.setStyle(styleId);
+            String candStyleId = run.getCTR().getRPr().getRStyleArray(0).getVal();
+            assertNotNull(candStyleId, "Expected to find a run style ID");
+            assertEquals(styleId, candStyleId);
 
-        document.close();
+            assertEquals(styleId, run.getStyle());
+        }
     }
 
     @Test
     void testGetEmptyStyle() throws IOException {
-        XWPFDocument document = new XWPFDocument();
-        final XWPFRun run = document.createParagraph().createRun();
-        assertEquals("", run.getStyle());
+        try (XWPFDocument document = new XWPFDocument()) {
+            final XWPFRun run = document.createParagraph().createRun();
+            assertEquals("", run.getStyle());
 
-        run.getCTR().addNewRPr();
-        assertEquals("", run.getStyle());
-        document.close();
+            run.getCTR().addNewRPr();
+            assertEquals("", run.getStyle());
+        }
     }
 
     @Test
     void testGetDepthWidth() throws IOException, InvalidFormatException {
-        try (XWPFDocument doc = XWPFTestDataSamples.openSampleDocument("TestDocument.docx")) {
+        try (XWPFDocument doc = openSampleDocument("TestDocument.docx")) {
             XWPFHeader hdr = doc.createHeader(HeaderFooterType.DEFAULT);
             XWPFParagraph p = hdr.createParagraph();
             XWPFRun r = p.createRun();
@@ -827,35 +819,28 @@ class TestXWPFRun {
                 "  The quick brown fox",
                 "\t\tjumped over the lazy dog"
         };
-        ByteArrayOutputStream bos = new ByteArrayOutputStream();
-        try (XWPFDocument doc = new XWPFDocument();) {
+        try (XWPFDocument doc1 = new XWPFDocument()) {
             for(String s : text) {
-                XWPFParagraph p1 = doc.createParagraph();
+                XWPFParagraph p1 = doc1.createParagraph();
                 XWPFRun r1 = p1.createRun();
                 r1.setText(s);
             }
 
-            doc.write(bos);
-            bos.flush();
-        }
-
-        try (
-                ByteArrayInputStream bis = new ByteArrayInputStream(bos.toByteArray());
-                XWPFDocument doc = new XWPFDocument(bis)
-        ) {
-            List<XWPFParagraph> paragraphs = doc.getParagraphs();
-            assertEquals(2, paragraphs.size());
-            for (int i = 0; i < text.length; i++) {
-                XWPFParagraph p1 = paragraphs.get(i);
-                String expected = text[i];
-                assertEquals(expected, p1.getText());
-                CTP ctp = p1.getCTP();
-                CTR ctr = ctp.getRArray(0);
-                CTText ctText = ctr.getTArray(0);
-                // if text has leading whitespace then expect xml-fragment to have xml:space="preserve" set
-                // <xml-fragment xml:space="preserve" xmlns:w="http://schemas.openxmlformats.org/wordprocessingml/2006/main">
-                boolean isWhitespace = Character.isWhitespace(expected.charAt(0));
-                assertEquals(isWhitespace, ctText.isSetSpace());
+            try (XWPFDocument doc2 = writeOutAndReadBack(doc1)) {
+                List<XWPFParagraph> paragraphs = doc2.getParagraphs();
+                assertEquals(2, paragraphs.size());
+                for (int i = 0; i < text.length; i++) {
+                    XWPFParagraph p1 = paragraphs.get(i);
+                    String expected = text[i];
+                    assertEquals(expected, p1.getText());
+                    CTP ctp = p1.getCTP();
+                    CTR ctr = ctp.getRArray(0);
+                    CTText ctText = ctr.getTArray(0);
+                    // if text has leading whitespace then expect xml-fragment to have xml:space="preserve" set
+                    // <xml-fragment xml:space="preserve" xmlns:w="http://schemas.openxmlformats.org/wordprocessingml/2006/main">
+                    boolean isWhitespace = Character.isWhitespace(expected.charAt(0));
+                    assertEquals(isWhitespace, ctText.isSetSpace());
+                }
             }
         }
     }
diff --git a/poi-scratchpad/src/main/java/org/apache/poi/hdgf/HDGFLZW.java b/poi-scratchpad/src/main/java/org/apache/poi/hdgf/HDGFLZW.java
index 9879eee028..5e70f033a2 100644
--- a/poi-scratchpad/src/main/java/org/apache/poi/hdgf/HDGFLZW.java
+++ b/poi-scratchpad/src/main/java/org/apache/poi/hdgf/HDGFLZW.java
@@ -16,11 +16,11 @@
 ==================================================================== */
 package org.apache.poi.hdgf;
 
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.util.LZWDecompresser;
 
 /**
@@ -53,7 +53,7 @@ public class HDGFLZW extends LZWDecompresser {
     * @throws IOException when the InputStream can't be read
     */
    public byte[] compress(InputStream src) throws IOException {
-      ByteArrayOutputStream res = new ByteArrayOutputStream();
+      UnsynchronizedByteArrayOutputStream res = new UnsynchronizedByteArrayOutputStream();
       compress(src,res);
       return res.toByteArray();
    }
diff --git a/poi-scratchpad/src/main/java/org/apache/poi/hemf/record/emf/HemfFill.java b/poi-scratchpad/src/main/java/org/apache/poi/hemf/record/emf/HemfFill.java
index 803fb98855..f1b668e3f0 100644
--- a/poi-scratchpad/src/main/java/org/apache/poi/hemf/record/emf/HemfFill.java
+++ b/poi-scratchpad/src/main/java/org/apache/poi/hemf/record/emf/HemfFill.java
@@ -26,8 +26,6 @@ import java.awt.geom.AffineTransform;
 import java.awt.geom.Area;
 import java.awt.geom.Point2D;
 import java.awt.geom.Rectangle2D;
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Collections;
@@ -36,6 +34,7 @@ import java.util.List;
 import java.util.Map;
 import java.util.function.Supplier;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.hemf.draw.HemfDrawProperties;
 import org.apache.poi.hemf.draw.HemfGraphics;
 import org.apache.poi.hwmf.draw.HwmfGraphics;
@@ -793,14 +792,14 @@ public final class HemfFill {
             return (long)undefinedSpace1 + bitmap.init(leis, dibSize);
         }
 
-        final ByteArrayOutputStream bos = new ByteArrayOutputStream(cbBmi+cbBits);
+        final UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream(cbBmi+cbBits);
         final long cbBmiSrcAct = IOUtils.copy(leis, bos, cbBmi);
         assert (cbBmiSrcAct == cbBmi);
         leis.skipFully(undefinedSpace2);
         final long cbBitsSrcAct = IOUtils.copy(leis, bos, cbBits);
         assert (cbBitsSrcAct == cbBits);
 
-        final LittleEndianInputStream leisDib = new LittleEndianInputStream(new ByteArrayInputStream(bos.toByteArray()));
+        final LittleEndianInputStream leisDib = new LittleEndianInputStream(bos.toInputStream());
         final int dibSizeAct = bitmap.init(leisDib, dibSize);
         assert (dibSizeAct <= dibSize);
         return (long)undefinedSpace1 + cbBmi + undefinedSpace2 + cbBits;
diff --git a/poi-scratchpad/src/main/java/org/apache/poi/hemf/record/emfplus/HemfPlusBrush.java b/poi-scratchpad/src/main/java/org/apache/poi/hemf/record/emfplus/HemfPlusBrush.java
index 71ade3fdb3..9739635c21 100644
--- a/poi-scratchpad/src/main/java/org/apache/poi/hemf/record/emfplus/HemfPlusBrush.java
+++ b/poi-scratchpad/src/main/java/org/apache/poi/hemf/record/emfplus/HemfPlusBrush.java
@@ -27,7 +27,6 @@ import java.awt.geom.AffineTransform;
 import java.awt.geom.Point2D;
 import java.awt.geom.Rectangle2D;
 import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.util.AbstractMap;
 import java.util.Arrays;
@@ -41,6 +40,7 @@ import java.util.function.Supplier;
 import java.util.stream.Collectors;
 import java.util.stream.IntStream;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.common.usermodel.GenericRecord;
 import org.apache.poi.hemf.draw.HemfDrawProperties;
 import org.apache.poi.hemf.draw.HemfGraphics;
@@ -399,7 +399,7 @@ public class HemfPlusBrush {
         }
 
         public byte[] getRawData(List<? extends EmfPlusObjectData> continuedObjectData) {
-            ByteArrayOutputStream bos = new ByteArrayOutputStream();
+            UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream();
             try {
                 bos.write(getBrushBytes());
                 if (continuedObjectData != null) {
@@ -473,6 +473,7 @@ public class HemfPlusBrush {
     public static class EmfPlusHatchBrushData implements EmfPlusBrushData {
         private EmfPlusHatchStyle style;
         private Color foreColor, backColor;
+        @Override
         public long init(LittleEndianInputStream leis, long dataSize) {
             style = EmfPlusHatchStyle.valueOf(leis.readInt());
             foreColor = readARGB(leis.readInt());
diff --git a/poi-scratchpad/src/main/java/org/apache/poi/hemf/record/emfplus/HemfPlusImage.java b/poi-scratchpad/src/main/java/org/apache/poi/hemf/record/emfplus/HemfPlusImage.java
index 840b752f37..1ea137dc1a 100644
--- a/poi-scratchpad/src/main/java/org/apache/poi/hemf/record/emfplus/HemfPlusImage.java
+++ b/poi-scratchpad/src/main/java/org/apache/poi/hemf/record/emfplus/HemfPlusImage.java
@@ -23,7 +23,6 @@ import java.awt.Color;
 import java.awt.geom.Rectangle2D;
 import java.awt.image.BufferedImage;
 import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.util.Collections;
 import java.util.LinkedHashMap;
@@ -33,6 +32,7 @@ import java.util.function.Supplier;
 
 import javax.imageio.ImageIO;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.hemf.draw.HemfDrawProperties;
 import org.apache.poi.hemf.draw.HemfGraphics;
 import org.apache.poi.hemf.record.emfplus.HemfPlusHeader.EmfPlusGraphicsVersion;
@@ -445,7 +445,7 @@ public class HemfPlusImage {
         }
 
         public byte[] getRawData(List<? extends EmfPlusObjectData> continuedObjectData) {
-            ByteArrayOutputStream bos = new ByteArrayOutputStream();
+            UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream();
             try {
                 bos.write(getImageData());
                 if (continuedObjectData != null) {
@@ -607,6 +607,7 @@ public class HemfPlusImage {
             return size + 5*LittleEndianConsts.INT_SIZE;
         }
 
+        @Override
         public EmfPlusGraphicsVersion getGraphicsVersion() {
             return graphicsVersion;
         }
diff --git a/poi-scratchpad/src/main/java/org/apache/poi/hemf/usermodel/HemfEmbeddedIterator.java b/poi-scratchpad/src/main/java/org/apache/poi/hemf/usermodel/HemfEmbeddedIterator.java
index 1b02478861..f94c05a598 100644
--- a/poi-scratchpad/src/main/java/org/apache/poi/hemf/usermodel/HemfEmbeddedIterator.java
+++ b/poi-scratchpad/src/main/java/org/apache/poi/hemf/usermodel/HemfEmbeddedIterator.java
@@ -18,7 +18,6 @@
 package org.apache.poi.hemf.usermodel;
 
 import java.awt.image.BufferedImage;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.util.ArrayDeque;
 import java.util.Deque;
@@ -27,6 +26,7 @@ import java.util.NoSuchElementException;
 
 import javax.imageio.ImageIO;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.hemf.record.emf.HemfComment;
 import org.apache.poi.hemf.record.emf.HemfComment.EmfComment;
 import org.apache.poi.hemf.record.emf.HemfComment.EmfCommentDataFormat;
@@ -273,7 +273,7 @@ public class HemfEmbeddedIterator implements Iterator<HwmfEmbedded> {
     private void compressGDIBitmap(EmfPlusImage img, HwmfEmbedded emb, HwmfEmbeddedType et) {
         BufferedImage bi = img.readGDIImage(emb.getRawData());
         try {
-            ByteArrayOutputStream bos = new ByteArrayOutputStream();
+            UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream();
             // use HwmfEmbeddedType literal for conversion
             ImageIO.write(bi, et.toString(), bos);
             emb.setData(bos.toByteArray());
@@ -298,7 +298,7 @@ public class HemfEmbeddedIterator implements Iterator<HwmfEmbedded> {
         int totalSize = epo.getTotalObjectSize();
         IOUtils.safelyAllocateCheck(totalSize, MAX_RECORD_LENGTH);
 
-        ByteArrayOutputStream bos = new ByteArrayOutputStream(epo.getTotalObjectSize());
+        UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream(epo.getTotalObjectSize());
         try {
             for (;;) {
                 bos.write(img.getImageData());
@@ -315,8 +315,8 @@ public class HemfEmbeddedIterator implements Iterator<HwmfEmbedded> {
                     return emb;
                 }
             }
-        } catch (IOException e) {
-            // ByteArrayOutputStream doesn't throw IOException
+        } catch (IOException ignored) {
+            // UnsynchronizedByteArrayOutputStream doesn't throw IOException
             return null;
         } finally {
             emb.setData(bos.toByteArray());
diff --git a/poi-scratchpad/src/main/java/org/apache/poi/hmef/CompressedRTF.java b/poi-scratchpad/src/main/java/org/apache/poi/hmef/CompressedRTF.java
index c3e2ab0c38..46988b9ec0 100644
--- a/poi-scratchpad/src/main/java/org/apache/poi/hmef/CompressedRTF.java
+++ b/poi-scratchpad/src/main/java/org/apache/poi/hmef/CompressedRTF.java
@@ -70,6 +70,7 @@ public final class CompressedRTF extends LZWDecompresser {
     *  if you need to know how much of the result is
     *  real. (Padding may be up to 7 bytes).
     */
+   @Override
    public void decompress(InputStream src, OutputStream res) throws IOException {
       // Validate the header on the front of the RTF
       compressedSize = LittleEndian.readInt(src);
diff --git a/poi-scratchpad/src/main/java/org/apache/poi/hslf/blip/EMF.java b/poi-scratchpad/src/main/java/org/apache/poi/hslf/blip/EMF.java
index e6bf60da16..ec8d2b2fec 100644
--- a/poi-scratchpad/src/main/java/org/apache/poi/hslf/blip/EMF.java
+++ b/poi-scratchpad/src/main/java/org/apache/poi/hslf/blip/EMF.java
@@ -19,11 +19,11 @@ package org.apache.poi.hslf.blip;
 
 import java.awt.Dimension;
 import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.util.zip.InflaterInputStream;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.ddf.EscherBSERecord;
 import org.apache.poi.ddf.EscherContainerRecord;
 import org.apache.poi.hslf.exceptions.HSLFException;
@@ -41,7 +41,7 @@ public final class EMF extends Metafile {
 
     /**
      * @deprecated Use {@link HSLFSlideShow#addPicture(byte[], PictureType)} or one of it's overloads to create new
-     *             {@link EMF}. This API led to detached {@link EMF} instances (See Bugzilla
+     *             EMF. This API led to detached EMF instances (See Bugzilla
      *             46122) and prevented adding additional functionality.
      */
     @Deprecated
@@ -64,23 +64,19 @@ public final class EMF extends Metafile {
 
     @Override
     public byte[] getData(){
-        try {
-            byte[] rawdata = getRawData();
+        byte[] rawdata = getRawData();
+        Header header = new Header();
+        header.read(rawdata, CHECKSUM_SIZE);
+
+        try (UnsynchronizedByteArrayOutputStream out = new UnsynchronizedByteArrayOutputStream();
+             InputStream is = new ByteArrayInputStream(rawdata);
+             InflaterInputStream inflater = new InflaterInputStream(is)) {
 
-            ByteArrayOutputStream out = new ByteArrayOutputStream();
-            InputStream is = new ByteArrayInputStream( rawdata );
-            Header header = new Header();
-            header.read(rawdata, CHECKSUM_SIZE);
             long len = IOUtils.skipFully(is,header.getSize() + (long)CHECKSUM_SIZE);
             assert(len == header.getSize() + CHECKSUM_SIZE);
 
-            InflaterInputStream inflater = new InflaterInputStream( is );
-            byte[] chunk = new byte[4096];
-            int count;
-            while ((count = inflater.read(chunk)) >=0 ) {
-                out.write(chunk,0,count);
-            }
-            inflater.close();
+            IOUtils.copy(inflater, out);
+
             return out.toByteArray();
         } catch (IOException e){
             throw new HSLFException(e);
@@ -129,13 +125,15 @@ public final class EMF extends Metafile {
      *
      * @return EMF signature ({@code 0x3D40} or {@code 0x3D50})
      */
+    @Override
     public int getSignature(){
         return (getUIDInstanceCount() == 1 ? 0x3D40 : 0x3D50);
     }
-    
+
     /**
      * Sets the EMF signature - either {@code 0x3D40} or {@code 0x3D50}
      */
+    @Override
     public void setSignature(int signature) {
         switch (signature) {
             case 0x3D40:
@@ -146,6 +144,6 @@ public final class EMF extends Metafile {
                 break;
             default:
                 throw new IllegalArgumentException(signature+" is not a valid instance/signature value for EMF");
-        }        
+        }
     }
 }
diff --git a/poi-scratchpad/src/main/java/org/apache/poi/hslf/blip/Metafile.java b/poi-scratchpad/src/main/java/org/apache/poi/hslf/blip/Metafile.java
index ea855d460e..ca0b01556e 100644
--- a/poi-scratchpad/src/main/java/org/apache/poi/hslf/blip/Metafile.java
+++ b/poi-scratchpad/src/main/java/org/apache/poi/hslf/blip/Metafile.java
@@ -20,11 +20,11 @@ package org.apache.poi.hslf.blip;
 import java.awt.Dimension;
 import java.awt.Rectangle;
 import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.OutputStream;
 import java.util.zip.DeflaterOutputStream;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.ddf.EscherBSERecord;
 import org.apache.poi.ddf.EscherContainerRecord;
 import org.apache.poi.hslf.usermodel.HSLFPictureData;
@@ -44,7 +44,7 @@ public abstract class Metafile extends HSLFPictureData {
 
     /**
      * @deprecated Use {@link HSLFSlideShow#addPicture(byte[], PictureType)} or one of it's overloads to create new
-     *             {@link Metafile}. This API led to detached {@link Metafile} instances (See Bugzilla
+     *             Metafile. This API led to detached Metafile instances (See Bugzilla
      *             46122) and prevented adding additional functionality.
      */
     @Deprecated
@@ -70,7 +70,7 @@ public abstract class Metafile extends HSLFPictureData {
      */
     public static class Header{
         private static final int RECORD_LENGTH = 34;
-        
+
         /**
          * size of the original file
          */
@@ -105,7 +105,7 @@ public abstract class Metafile extends HSLFPictureData {
             @SuppressWarnings("resource")
             LittleEndianInputStream leis = new LittleEndianInputStream(
                 new ByteArrayInputStream(data, offset, RECORD_LENGTH));
-            
+
             wmfsize = leis.readInt();
 
             int left = leis.readInt();
@@ -126,7 +126,7 @@ public abstract class Metafile extends HSLFPictureData {
         public void write(OutputStream out) throws IOException {
             @SuppressWarnings("resource")
             LittleEndianOutputStream leos = new LittleEndianOutputStream(out);
-            
+
             //hmf
             leos.writeInt(wmfsize);
             //left
@@ -140,8 +140,8 @@ public abstract class Metafile extends HSLFPictureData {
             //inch
             leos.writeInt(size.width);
             //inch
-            leos.writeInt(size.height); 
-            leos.writeInt(zipsize); 
+            leos.writeInt(size.height);
+            leos.writeInt(zipsize);
             leos.writeByte(compression);
             leos.writeByte(filter);
         }
@@ -187,15 +187,15 @@ public abstract class Metafile extends HSLFPictureData {
         public int getSize(){
             return 34;
         }
-        
+
         public int getWmfSize() {
             return wmfsize;
         }
-        
+
         protected void setWmfSize(int wmfSize) {
             this.wmfsize = wmfSize;
         }
-        
+
         protected void setZipSize(int zipSize) {
             this.zipsize = zipSize;
         }
@@ -203,25 +203,25 @@ public abstract class Metafile extends HSLFPictureData {
         public Rectangle getBounds() {
             return (Rectangle)bounds.clone();
         }
-        
+
         protected void setBounds(Rectangle bounds) {
             this.bounds.setBounds(bounds);
         }
-        
+
         protected void setDimension(Dimension size) {
             this.size.setSize(size);
         }
     }
 
     protected static byte[] compress(byte[] bytes, int offset, int length) {
-        ByteArrayOutputStream out = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream out = new UnsynchronizedByteArrayOutputStream();
         try (DeflaterOutputStream deflater = new DeflaterOutputStream(out)) {
             deflater.write(bytes, offset, length);
-        } catch (IOException e) {
+        } catch (IOException ignored) {
             // IOException won't get thrown by the DeflaterOutputStream in this configuration because:
-            //  1. ByteArrayOutputStream doesn't throw an IOException during writes.
+            //  1. UnsynchronizedByteArrayOutputStream doesn't throw an IOException during writes.
             //  2. The DeflaterOutputStream is not finished until we're done writing.
-            throw new AssertionError("Won't happen", e);
+            throw new AssertionError("Won't happen", ignored);
         }
         return out.toByteArray();
     }
diff --git a/poi-scratchpad/src/main/java/org/apache/poi/hslf/blip/PICT.java b/poi-scratchpad/src/main/java/org/apache/poi/hslf/blip/PICT.java
index a6c2765ec7..dc1e93cc67 100644
--- a/poi-scratchpad/src/main/java/org/apache/poi/hslf/blip/PICT.java
+++ b/poi-scratchpad/src/main/java/org/apache/poi/hslf/blip/PICT.java
@@ -17,13 +17,15 @@
 
 package org.apache.poi.hslf.blip;
 
+import static org.apache.logging.log4j.util.Unbox.box;
+
 import java.awt.Dimension;
 import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.EOFException;
 import java.io.IOException;
 import java.util.zip.InflaterInputStream;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.poi.ddf.EscherBSERecord;
@@ -36,8 +38,6 @@ import org.apache.poi.util.Internal;
 import org.apache.poi.util.Removal;
 import org.apache.poi.util.Units;
 
-import static org.apache.logging.log4j.util.Unbox.box;
-
 /**
  * Represents Macintosh PICT picture data.
  */
@@ -46,7 +46,7 @@ public final class PICT extends Metafile {
 
     /**
      * @deprecated Use {@link HSLFSlideShow#addPicture(byte[], PictureType)} or one of it's overloads to create new
-     *             {@link PICT}. This API led to detached {@link PICT} instances (See Bugzilla
+     *             PICT. This API led to detached PICT instances (See Bugzilla
      *             46122) and prevented adding additional functionality.
      */
     @Deprecated
@@ -72,7 +72,7 @@ public final class PICT extends Metafile {
         byte[] rawdata = getRawData();
         try {
             byte[] macheader = new byte[512];
-            ByteArrayOutputStream out = new ByteArrayOutputStream();
+            UnsynchronizedByteArrayOutputStream out = new UnsynchronizedByteArrayOutputStream();
             out.write(macheader);
             int pos = CHECKSUM_SIZE*getUIDInstanceCount();
             byte[] pict = read(rawdata, pos);
@@ -93,7 +93,7 @@ public final class PICT extends Metafile {
             throw new EOFException();
         }
         byte[] chunk = new byte[4096];
-        ByteArrayOutputStream out = new ByteArrayOutputStream(header.getWmfSize());
+        UnsynchronizedByteArrayOutputStream out = new UnsynchronizedByteArrayOutputStream(header.getWmfSize());
         try (InflaterInputStream inflater = new InflaterInputStream(bis)) {
             int count;
             while ((count = inflater.read(chunk)) >= 0) {
@@ -163,6 +163,7 @@ public final class PICT extends Metafile {
      *
      * @return PICT signature ({@code 0x5420} or {@code 0x5430})
      */
+    @Override
     public int getSignature(){
         return (getUIDInstanceCount() == 1 ? 0x5420 : 0x5430);
     }
@@ -170,6 +171,7 @@ public final class PICT extends Metafile {
     /**
      * Sets the PICT signature - either {@code 0x5420} or {@code 0x5430}
      */
+    @Override
     public void setSignature(int signature) {
         switch (signature) {
             case 0x5420:
diff --git a/poi-scratchpad/src/main/java/org/apache/poi/hslf/blip/WMF.java b/poi-scratchpad/src/main/java/org/apache/poi/hslf/blip/WMF.java
index 55b74bdb6f..6a039510c6 100644
--- a/poi-scratchpad/src/main/java/org/apache/poi/hslf/blip/WMF.java
+++ b/poi-scratchpad/src/main/java/org/apache/poi/hslf/blip/WMF.java
@@ -19,11 +19,11 @@ package org.apache.poi.hslf.blip;
 
 import java.awt.Dimension;
 import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.util.zip.InflaterInputStream;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.ddf.EscherBSERecord;
 import org.apache.poi.ddf.EscherContainerRecord;
 import org.apache.poi.hslf.exceptions.HSLFException;
@@ -41,7 +41,7 @@ public final class WMF extends Metafile {
 
     /**
      * @deprecated Use {@link HSLFSlideShow#addPicture(byte[], PictureType)} or one of it's overloads to create new
-     *             {@link WMF}. This API led to detached {@link WMF} instances (See Bugzilla
+     *             WMF. This API led to detached WMF instances (See Bugzilla
      *             46122) and prevented adding additional functionality.
      */
     @Deprecated
@@ -67,7 +67,6 @@ public final class WMF extends Metafile {
         try {
             byte[] rawdata = getRawData();
 
-            ByteArrayOutputStream out = new ByteArrayOutputStream();
             InputStream is = new ByteArrayInputStream( rawdata );
             Header header = new Header();
             header.read(rawdata, CHECKSUM_SIZE*getUIDInstanceCount());
@@ -76,15 +75,12 @@ public final class WMF extends Metafile {
             assert(skipped == skipLen);
 
             ImageHeaderWMF aldus = new ImageHeaderWMF(header.getBounds());
+            UnsynchronizedByteArrayOutputStream out = new UnsynchronizedByteArrayOutputStream();
             aldus.write(out);
 
-            InflaterInputStream inflater = new InflaterInputStream( is );
-            byte[] chunk = new byte[4096];
-            int count;
-            while ((count = inflater.read(chunk)) >=0 ) {
-                out.write(chunk,0,count);
+            try (InflaterInputStream inflater = new InflaterInputStream( is )) {
+                IOUtils.copy(inflater, out);
             }
-            inflater.close();
             return out.toByteArray();
         } catch (IOException e){
             throw new HSLFException(e);
@@ -133,6 +129,7 @@ public final class WMF extends Metafile {
     /**
      * WMF signature is either {@code 0x2160} or {@code 0x2170}
      */
+    @Override
     public int getSignature(){
         return (getUIDInstanceCount() == 1 ? 0x2160 : 0x2170);
     }
@@ -140,6 +137,7 @@ public final class WMF extends Metafile {
     /**
      * Sets the WMF signature - either {@code 0x2160} or {@code 0x2170}
      */
+    @Override
     public void setSignature(int signature) {
         switch (signature) {
             case 0x2160:
diff --git a/poi-scratchpad/src/main/java/org/apache/poi/hslf/dev/PPTXMLDump.java b/poi-scratchpad/src/main/java/org/apache/poi/hslf/dev/PPTXMLDump.java
index 4e431976a3..b15d37c987 100644
--- a/poi-scratchpad/src/main/java/org/apache/poi/hslf/dev/PPTXMLDump.java
+++ b/poi-scratchpad/src/main/java/org/apache/poi/hslf/dev/PPTXMLDump.java
@@ -17,7 +17,6 @@
 
 package org.apache.poi.hslf.dev;
 
-import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.FileOutputStream;
 import java.io.IOException;
@@ -28,6 +27,7 @@ import java.io.Writer;
 import java.nio.charset.StandardCharsets;
 import java.util.Arrays;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.hslf.record.RecordTypes;
 import org.apache.poi.hslf.usermodel.HSLFSlideShow;
 import org.apache.poi.poifs.filesystem.DirectoryNode;
@@ -41,19 +41,15 @@ import org.apache.poi.util.LittleEndianConsts;
  */
 
 public final class PPTXMLDump {
-
-    //arbitrarily selected; may need to increase
-    private static final int MAX_RECORD_LENGTH = 1_000_000;
-
     private static final int HEADER_SIZE = 8; //size of the record header
     private static final int PICT_HEADER_SIZE = 25; //size of the picture header
     private static final String PICTURES_ENTRY = "Pictures";
     private static final String CR = System.getProperty("line.separator");
 
     private Writer out;
-    private byte[] docstream;
-    private byte[] pictstream;
-    private boolean hexHeader = true;
+    private final byte[] docstream;
+    private final byte[] pictstream;
+    private final boolean hexHeader = true;
 
     public PPTXMLDump(File ppt) throws IOException {
         try (POIFSFileSystem fs = new POIFSFileSystem(ppt, true)) {
@@ -68,8 +64,8 @@ public final class PPTXMLDump {
         if (!dn.hasEntry(entry)) {
             return null;
         }
-        try (InputStream is = dn.createDocumentInputStream(entry)) {
-            ByteArrayOutputStream bos = new ByteArrayOutputStream();
+        try (InputStream is = dn.createDocumentInputStream(entry);
+            UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream()) {
             IOUtils.copy(is, bos);
             return bos.toByteArray();
         }
@@ -77,7 +73,7 @@ public final class PPTXMLDump {
 
     /**
      * Dump the structure of the supplied PPT file into XML
-     * @param outWriter <code>Writer</code> to write out
+     * @param outWriter {@code Writer} to write out
      * @throws java.io.IOException If writing to the writer fails
      */
     public void dump(Writer outWriter) throws IOException {
@@ -229,7 +225,7 @@ public final class PPTXMLDump {
 
 
     /**
-     *  write a string to <code>out</code> with the specified padding
+     *  write a string to {@code out} with the specified padding
      */
     private static void write(Writer out, String str, int padding) throws IOException {
         for (int i = 0; i < padding; i++) out.write("  ");
@@ -250,7 +246,7 @@ public final class PPTXMLDump {
     }
 
     /**
-     *  dump binary data to <code>out</code> with the specified padding
+     *  dump binary data to {@code out} with the specified padding
      */
     private static void dump(Writer out, byte[] data, int offset, int length, int padding, boolean nl) throws IOException {
         int linesize = 25;
diff --git a/poi-scratchpad/src/main/java/org/apache/poi/hslf/dev/SlideIdListing.java b/poi-scratchpad/src/main/java/org/apache/poi/hslf/dev/SlideIdListing.java
index e80cbc18ec..b335752e9c 100644
--- a/poi-scratchpad/src/main/java/org/apache/poi/hslf/dev/SlideIdListing.java
+++ b/poi-scratchpad/src/main/java/org/apache/poi/hslf/dev/SlideIdListing.java
@@ -17,10 +17,10 @@
 
 package org.apache.poi.hslf.dev;
 
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.util.Map;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.hslf.record.Document;
 import org.apache.poi.hslf.record.Notes;
 import org.apache.poi.hslf.record.NotesAtom;
@@ -136,7 +136,7 @@ public final class SlideIdListing {
                         System.out.println("  Knows about sheet " + id);
                         System.out.println("    That sheet lives at " + offset);
 
-                        Record atPos = findRecordAtPos(offset.intValue());
+                        Record atPos = findRecordAtPos(offset);
                         System.out.println("    The record at that pos is of type " + atPos.getRecordType());
                         System.out.println("    The record at that pos has class " + atPos.getClass().getName());
 
@@ -147,7 +147,7 @@ public final class SlideIdListing {
                 }
 
                 // Increase the position by the on disk size
-                ByteArrayOutputStream baos = new ByteArrayOutputStream();
+                UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
                 r.writeOut(baos);
                 pos += baos.size();
             }
diff --git a/poi-scratchpad/src/main/java/org/apache/poi/hslf/dev/SlideShowRecordDumper.java b/poi-scratchpad/src/main/java/org/apache/poi/hslf/dev/SlideShowRecordDumper.java
index 88b6407cab..eb7a1a7ece 100644
--- a/poi-scratchpad/src/main/java/org/apache/poi/hslf/dev/SlideShowRecordDumper.java
+++ b/poi-scratchpad/src/main/java/org/apache/poi/hslf/dev/SlideShowRecordDumper.java
@@ -17,12 +17,11 @@
 
 package org.apache.poi.hslf.dev;
 
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.PrintStream;
-import java.util.List;
 import java.util.Locale;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.ddf.DefaultEscherRecordFactory;
 import org.apache.poi.ddf.EscherContainerRecord;
 import org.apache.poi.ddf.EscherRecord;
@@ -44,9 +43,9 @@ import org.apache.poi.util.HexDump;
 public final class SlideShowRecordDumper {
     static final String tabs = "\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t";
 
-    private boolean optVerbose;
-    private boolean optEscher;
-    private HSLFSlideShowImpl doc;
+    private final boolean optVerbose;
+    private final boolean optEscher;
+    private final HSLFSlideShowImpl doc;
     private final PrintStream ps;
 
     /**
@@ -59,7 +58,7 @@ public final class SlideShowRecordDumper {
 
         int ndx = 0;
         for (; ndx < args.length; ndx++) {
-            if (!args[ndx].substring(0, 1).equals("-"))
+            if (args[ndx].charAt(0) != '-')
                 break;
 
             if (args[ndx].equals("-escher")) {
@@ -147,7 +146,7 @@ public final class SlideShowRecordDumper {
     public int getDiskLen(org.apache.poi.hslf.record.Record r) throws IOException {
         int diskLen = 0;
         if (r != null) {
-            ByteArrayOutputStream baos = new ByteArrayOutputStream();
+            UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
             r.writeOut(baos);
             diskLen = baos.size();
         }
@@ -159,7 +158,7 @@ public final class SlideShowRecordDumper {
             return "<<null>>";
         }
 
-        ByteArrayOutputStream baos = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
         r.writeOut(baos);
         byte[] b = baos.toByteArray();
         return HexDump.dump(b, 0, 0);
@@ -259,7 +258,7 @@ public final class SlideShowRecordDumper {
             if (optEscher && cname.equals("PPDrawing")) {
                 DefaultEscherRecordFactory factory = new HSLFEscherRecordFactory();
 
-                ByteArrayOutputStream baos = new ByteArrayOutputStream();
+                UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
                 r.writeOut(baos);
                 byte[] b = baos.toByteArray();
 
diff --git a/poi-scratchpad/src/main/java/org/apache/poi/hslf/dev/UserEditAndPersistListing.java b/poi-scratchpad/src/main/java/org/apache/poi/hslf/dev/UserEditAndPersistListing.java
index 116582e7f3..d17eafc346 100644
--- a/poi-scratchpad/src/main/java/org/apache/poi/hslf/dev/UserEditAndPersistListing.java
+++ b/poi-scratchpad/src/main/java/org/apache/poi/hslf/dev/UserEditAndPersistListing.java
@@ -17,10 +17,10 @@
 
 package org.apache.poi.hslf.dev;
 
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.util.Map;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.hslf.record.CurrentUserAtom;
 import org.apache.poi.hslf.record.PersistPtrHolder;
 import org.apache.poi.hslf.record.PositionDependentRecord;
@@ -68,7 +68,7 @@ public final class UserEditAndPersistListing {
 						System.out.println("  Knows about sheet " + id);
 						System.out.println("    That sheet lives at " + offset);
 
-						Record atPos = findRecordAtPos(offset.intValue());
+						Record atPos = findRecordAtPos(offset);
 						System.out.println("    The record at that pos is of type " + atPos.getRecordType());
 						System.out.println("    The record at that pos has class " + atPos.getClass().getName());
 
@@ -79,7 +79,7 @@ public final class UserEditAndPersistListing {
 				}
 
 				// Increase the position by the on disk size
-				ByteArrayOutputStream baos = new ByteArrayOutputStream();
+				UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
 				r.writeOut(baos);
 				pos += baos.size();
 			}
@@ -99,7 +99,7 @@ public final class UserEditAndPersistListing {
 				}
 
 				// Increase the position by the on disk size
-				ByteArrayOutputStream baos = new ByteArrayOutputStream();
+				UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
 				r.writeOut(baos);
 				pos += baos.size();
 			}
diff --git a/poi-scratchpad/src/main/java/org/apache/poi/hslf/model/textproperties/TextPropCollection.java b/poi-scratchpad/src/main/java/org/apache/poi/hslf/model/textproperties/TextPropCollection.java
index 9155731dcd..62c2f935f3 100644
--- a/poi-scratchpad/src/main/java/org/apache/poi/hslf/model/textproperties/TextPropCollection.java
+++ b/poi-scratchpad/src/main/java/org/apache/poi/hslf/model/textproperties/TextPropCollection.java
@@ -17,7 +17,6 @@
 
 package org.apache.poi.hslf.model.textproperties;
 
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.OutputStream;
 import java.util.ArrayList;
@@ -29,6 +28,7 @@ import java.util.Map;
 import java.util.Objects;
 import java.util.function.Supplier;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.poi.common.Duplicatable;
@@ -355,10 +355,10 @@ public class TextPropCollection implements GenericRecord, Duplicatable {
 
     public String toString() {
         StringBuilder out = new StringBuilder();
-        out.append("  chars covered: " + getCharactersCovered());
-        out.append("  special mask flags: 0x" + HexDump.toHex(getSpecialMask()) + "\n");
+        out.append("  chars covered: ").append(getCharactersCovered());
+        out.append("  special mask flags: 0x").append(HexDump.toHex(getSpecialMask())).append("\n");
         if (textPropType == TextPropType.paragraph) {
-            out.append("  indent level: "+getIndentLevel()+"\n");
+            out.append("  indent level: ").append(getIndentLevel()).append("\n");
         }
         for(TextProp p : getTextPropList()) {
             out.append("    ");
@@ -369,7 +369,7 @@ public class TextPropCollection implements GenericRecord, Duplicatable {
                 int i = 0;
                 for (String s : bm.getSubPropNames()) {
                     if (bm.getSubPropMatches()[i]) {
-                        out.append("          " + s + " = " + bm.getSubValue(i) + "\n");
+                        out.append("          ").append(s).append(" = ").append(bm.getSubValue(i)).append("\n");
                     }
                     i++;
                 }
@@ -379,7 +379,7 @@ public class TextPropCollection implements GenericRecord, Duplicatable {
         out.append("  bytes that would be written: \n");
 
         try {
-            ByteArrayOutputStream baos = new ByteArrayOutputStream();
+            UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
             writeOut(baos);
             byte[] b = baos.toByteArray();
             out.append(HexDump.dump(b, 0, 0));
diff --git a/poi-scratchpad/src/main/java/org/apache/poi/hslf/record/ColorSchemeAtom.java b/poi-scratchpad/src/main/java/org/apache/poi/hslf/record/ColorSchemeAtom.java
index bd2ac34d98..7a8dc9dbf6 100644
--- a/poi-scratchpad/src/main/java/org/apache/poi/hslf/record/ColorSchemeAtom.java
+++ b/poi-scratchpad/src/main/java/org/apache/poi/hslf/record/ColorSchemeAtom.java
@@ -17,7 +17,6 @@
 
 package org.apache.poi.hslf.record;
 
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.OutputStream;
 import java.util.Arrays;
@@ -26,6 +25,7 @@ import java.util.LinkedHashMap;
 import java.util.Map;
 import java.util.function.Supplier;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.hslf.exceptions.HSLFException;
 import org.apache.poi.util.LittleEndian;
 
@@ -36,9 +36,9 @@ import org.apache.poi.util.LittleEndian;
  *  defines the colours to be used
  */
 public final class ColorSchemeAtom extends RecordAtom {
-	private byte[] _header;
-	private static long _type = 2032l;
+	private static final long _type = 2032L;
 
+	private final byte[] _header;
 	private int backgroundColourRGB;
 	private int textAndLinesColourRGB;
 	private int shadowsColourRGB;
@@ -99,8 +99,7 @@ public final class ColorSchemeAtom extends RecordAtom {
 	 */
 	protected ColorSchemeAtom(byte[] source, int start, int len) {
 		// Sanity Checking - we're always 40 bytes long
-		if(len < 40) {
-			len = 40;
+		if (len < 40) {
 			if(source.length - start < 40) {
 				throw new HSLFException("Not enough data to form a ColorSchemeAtom (always 40 bytes long) - found " + (source.length - start));
 			}
@@ -155,7 +154,7 @@ public final class ColorSchemeAtom extends RecordAtom {
 		byte[] ret = new byte[3];
 
 		// Serialise to bytes, then grab the right ones out
-		ByteArrayOutputStream baos = new ByteArrayOutputStream();
+		UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
 		try {
 			writeLittleEndian(rgb,baos);
 		} catch(IOException ie) {
diff --git a/poi-scratchpad/src/main/java/org/apache/poi/hslf/record/CurrentUserAtom.java b/poi-scratchpad/src/main/java/org/apache/poi/hslf/record/CurrentUserAtom.java
index ebb3fc01b9..e9e16b91ed 100644
--- a/poi-scratchpad/src/main/java/org/apache/poi/hslf/record/CurrentUserAtom.java
+++ b/poi-scratchpad/src/main/java/org/apache/poi/hslf/record/CurrentUserAtom.java
@@ -23,12 +23,11 @@ package org.apache.poi.hslf.record;
 import static org.apache.logging.log4j.util.Unbox.box;
 import static org.apache.poi.hslf.usermodel.HSLFSlideShow.PP95_DOCUMENT;
 
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.poi.hslf.exceptions.CorruptPowerPointFileException;
@@ -267,12 +266,12 @@ public class CurrentUserAtom
 	 */
 	public void writeToFS(POIFSFileSystem fs) throws IOException {
 		// Grab contents
-		ByteArrayOutputStream baos = new ByteArrayOutputStream();
-		writeOut(baos);
-		ByteArrayInputStream bais =
-			new ByteArrayInputStream(baos.toByteArray());
-
-		// Write out
-		fs.createOrUpdateDocument(bais,"Current User");
+		try (UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream()) {
+			writeOut(baos);
+			try (InputStream is = baos.toInputStream()) {
+				// Write out
+				fs.createOrUpdateDocument(is, "Current User");
+			}
+		}
 	}
 }
diff --git a/poi-scratchpad/src/main/java/org/apache/poi/hslf/record/DocumentAtom.java b/poi-scratchpad/src/main/java/org/apache/poi/hslf/record/DocumentAtom.java
index 273c3a6a2c..4764c91d21 100644
--- a/poi-scratchpad/src/main/java/org/apache/poi/hslf/record/DocumentAtom.java
+++ b/poi-scratchpad/src/main/java/org/apache/poi/hslf/record/DocumentAtom.java
@@ -66,7 +66,7 @@ public final class DocumentAtom extends RecordAtom {
 
 
 	private final byte[] _header = new byte[8];
-	private static long _type = RecordTypes.DocumentAtom.typeID;
+	private static final long _type = RecordTypes.DocumentAtom.typeID;
 
 	private long slideSizeX; // PointAtom, assume 1st 4 bytes = X
 	private long slideSizeY; // PointAtom, assume 2nd 4 bytes = Y
@@ -75,18 +75,18 @@ public final class DocumentAtom extends RecordAtom {
 	private long serverZoomFrom; // RatioAtom, assume 1st 4 bytes = from
 	private long serverZoomTo;   // RatioAtom, assume 2nd 4 bytes = to
 
-	private long notesMasterPersist; // ref to NotesMaster, 0 if none
-	private long handoutMasterPersist; // ref to HandoutMaster, 0 if none
+	private final long notesMasterPersist; // ref to NotesMaster, 0 if none
+	private final long handoutMasterPersist; // ref to HandoutMaster, 0 if none
 
-	private int firstSlideNum;
+	private final int firstSlideNum;
 	private int slideSizeType; // see DocumentAtom.SlideSize
 
 	private byte saveWithFonts;
-	private byte omitTitlePlace;
-	private byte rightToLeft;
-	private byte showComments;
+	private final byte omitTitlePlace;
+	private final byte rightToLeft;
+	private final byte showComments;
 
-	private byte[] reserved;
+	private final byte[] reserved;
 
 
 	public long getSlideSizeX() { return slideSizeX; }
@@ -197,12 +197,14 @@ public final class DocumentAtom extends RecordAtom {
 	/**
 	 * We are of type 1001
 	 */
+	@Override
 	public long getRecordType() { return _type; }
 
 	/**
 	 * Write the contents of the record back, so it can be written
 	 *  to disk
 	 */
+	@Override
 	public void writeOut(OutputStream out) throws IOException {
 		// Header
 		out.write(_header);
diff --git a/poi-scratchpad/src/main/java/org/apache/poi/hslf/record/EscherTextboxWrapper.java b/poi-scratchpad/src/main/java/org/apache/poi/hslf/record/EscherTextboxWrapper.java
index 7a47e9fd4e..751bf291f9 100644
--- a/poi-scratchpad/src/main/java/org/apache/poi/hslf/record/EscherTextboxWrapper.java
+++ b/poi-scratchpad/src/main/java/org/apache/poi/hslf/record/EscherTextboxWrapper.java
@@ -17,12 +17,12 @@
 
 package org.apache.poi.hslf.record;
 
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.OutputStream;
 import java.util.Map;
 import java.util.function.Supplier;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.ddf.EscherTextboxRecord;
 import org.apache.poi.util.GenericRecordUtil;
 
@@ -34,7 +34,7 @@ import org.apache.poi.util.GenericRecordUtil;
  *  parent PPDrawing) will do the actual write out
  */
 public final class EscherTextboxWrapper extends RecordContainer {
-	private EscherTextboxRecord _escherRecord;
+	private final EscherTextboxRecord _escherRecord;
 	private long _type;
 	private int shapeId;
 	private StyleTextPropAtom styleTextPropAtom;
@@ -75,6 +75,7 @@ public final class EscherTextboxWrapper extends RecordContainer {
 	/**
 	 * Return the type of the escher record (normally in the 0xFnnn range)
 	 */
+	@Override
 	public long getRecordType() { return _type; }
 
 	/**
@@ -83,11 +84,12 @@ public final class EscherTextboxWrapper extends RecordContainer {
 	 *  layer to do. Must be called before writeOut/serialize is called
 	 *  on the underlying Escher object!
 	 */
+	@Override
 	public void writeOut(OutputStream out) throws IOException {
 		// Write out our children, and stuff them into the Escher layer
 
 		// Grab the children's data
-		ByteArrayOutputStream baos = new ByteArrayOutputStream();
+		UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
 		for (org.apache.poi.hslf.record.Record r : _children) r.writeOut(baos);
 		byte[] data = baos.toByteArray();
 
diff --git a/poi-scratchpad/src/main/java/org/apache/poi/hslf/record/ExOleObjStg.java b/poi-scratchpad/src/main/java/org/apache/poi/hslf/record/ExOleObjStg.java
index 4fc8a838e0..8aa091fdb2 100644
--- a/poi-scratchpad/src/main/java/org/apache/poi/hslf/record/ExOleObjStg.java
+++ b/poi-scratchpad/src/main/java/org/apache/poi/hslf/record/ExOleObjStg.java
@@ -18,7 +18,6 @@
 package org.apache.poi.hslf.record;
 
 import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
@@ -28,7 +27,8 @@ import java.util.function.Supplier;
 import java.util.zip.DeflaterOutputStream;
 import java.util.zip.InflaterInputStream;
 
-import org.apache.poi.util.BoundedInputStream;
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
+import org.apache.commons.io.input.BoundedInputStream;
 import org.apache.poi.util.GenericRecordUtil;
 import org.apache.poi.util.IOUtils;
 import org.apache.poi.util.LittleEndian;
@@ -124,7 +124,7 @@ public class ExOleObjStg extends PositionDependentRecordAtom implements PersistR
      * @param data the embedded data.
      */
      public void setData(byte[] data) throws IOException {
-        ByteArrayOutputStream out = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream out = new UnsynchronizedByteArrayOutputStream();
         //first four bytes is the length of the raw data
         byte[] b = new byte[4];
         LittleEndian.putInt(b, 0, data.length);
@@ -133,6 +133,7 @@ public class ExOleObjStg extends PositionDependentRecordAtom implements PersistR
         DeflaterOutputStream def = new DeflaterOutputStream(out);
         def.write(data, 0, data.length);
         def.finish();
+        // TODO: CHECK if it's correct that DeflaterOutputStream is only finished and not closed?
         _data = out.toByteArray();
         LittleEndian.putInt(_header, 4, _data.length);
     }
@@ -142,6 +143,7 @@ public class ExOleObjStg extends PositionDependentRecordAtom implements PersistR
      *
      * @return the record type.
      */
+    @Override
     public long getRecordType() {
         return RecordTypes.ExOleObjStg.typeID;
     }
@@ -162,6 +164,7 @@ public class ExOleObjStg extends PositionDependentRecordAtom implements PersistR
      * @param out the output stream to write to.
      * @throws IOException if an error occurs.
      */
+    @Override
     public void writeOut(OutputStream out) throws IOException {
         out.write(_header);
         out.write(_data);
@@ -171,6 +174,7 @@ public class ExOleObjStg extends PositionDependentRecordAtom implements PersistR
      * Fetch our sheet ID, as found from a PersistPtrHolder.
      * Should match the RefId of our matching SlidePersistAtom
      */
+    @Override
     public int getPersistId() {
         return _persistId;
     }
@@ -178,6 +182,7 @@ public class ExOleObjStg extends PositionDependentRecordAtom implements PersistR
     /**
      * Set our sheet ID, as found from a PersistPtrHolder
      */
+    @Override
     public void setPersistId(int id) {
         _persistId = id;
     }
diff --git a/poi-scratchpad/src/main/java/org/apache/poi/hslf/record/HSLFEscherClientDataRecord.java b/poi-scratchpad/src/main/java/org/apache/poi/hslf/record/HSLFEscherClientDataRecord.java
index af0e0a5ec5..47efe8e829 100644
--- a/poi-scratchpad/src/main/java/org/apache/poi/hslf/record/HSLFEscherClientDataRecord.java
+++ b/poi-scratchpad/src/main/java/org/apache/poi/hslf/record/HSLFEscherClientDataRecord.java
@@ -17,11 +17,11 @@
 
 package org.apache.poi.hslf.record;
 
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.ddf.EscherClientDataRecord;
 import org.apache.poi.ddf.EscherRecordFactory;
 import org.apache.poi.ddf.EscherSerializationListener;
@@ -49,7 +49,7 @@ public class HSLFEscherClientDataRecord extends EscherClientDataRecord {
         super(other);
         // TODO: for now only reference others children, later copy them when Record.copy is available
         // other._childRecords.stream().map(Record::copy).forEach(_childRecords::add);
-        other._childRecords.addAll(other._childRecords);
+        _childRecords.addAll(other._childRecords);
     }
 
 
@@ -96,15 +96,14 @@ public class HSLFEscherClientDataRecord extends EscherClientDataRecord {
 
     @Override
     public byte[] getRemainingData() {
-        ByteArrayOutputStream bos = new ByteArrayOutputStream();
-        try {
+        try (UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream()) {
             for (org.apache.poi.hslf.record.Record r : _childRecords) {
                 r.writeOut(bos);
             }
+            return bos.toByteArray();
         } catch (IOException e) {
             throw new HSLFException(e);
         }
-        return bos.toByteArray();
     }
 
     @Override
@@ -121,6 +120,7 @@ public class HSLFEscherClientDataRecord extends EscherClientDataRecord {
         }
     }
 
+    @Override
     public String getRecordName() {
         return "HSLFClientData";
     }
diff --git a/poi-scratchpad/src/main/java/org/apache/poi/hslf/record/PPDrawingGroup.java b/poi-scratchpad/src/main/java/org/apache/poi/hslf/record/PPDrawingGroup.java
index 6ff8b4577f..3bc4f0fe57 100644
--- a/poi-scratchpad/src/main/java/org/apache/poi/hslf/record/PPDrawingGroup.java
+++ b/poi-scratchpad/src/main/java/org/apache/poi/hslf/record/PPDrawingGroup.java
@@ -17,13 +17,13 @@
 
 package org.apache.poi.hslf.record;
 
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.OutputStream;
 import java.util.Arrays;
 import java.util.Map;
 import java.util.function.Supplier;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.ddf.DefaultEscherRecordFactory;
 import org.apache.poi.ddf.EscherContainerRecord;
 import org.apache.poi.ddf.EscherDggRecord;
@@ -44,8 +44,8 @@ public final class PPDrawingGroup extends RecordAtom {
     private static final int MAX_RECORD_LENGTH = 10_485_760;
 
 
-    private byte[] _header;
-    private EscherContainerRecord dggContainer;
+    private final byte[] _header;
+    private final EscherContainerRecord dggContainer;
     //cached dgg
     private EscherDggRecord dgg;
 
@@ -65,6 +65,7 @@ public final class PPDrawingGroup extends RecordAtom {
     /**
      * We are type 1035
      */
+    @Override
     public long getRecordType() {
         return RecordTypes.PPDrawingGroup.typeID;
     }
@@ -72,17 +73,19 @@ public final class PPDrawingGroup extends RecordAtom {
     /**
      * We're pretending to be an atom, so return null
      */
+    @Override
     public org.apache.poi.hslf.record.Record[] getChildRecords() {
         return null;
     }
 
+    @Override
     public void writeOut(OutputStream out) throws IOException {
-        ByteArrayOutputStream bout = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream bout = new UnsynchronizedByteArrayOutputStream();
         for (EscherRecord r : dggContainer) {
             if (r.getRecordId() == EscherContainerRecord.BSTORE_CONTAINER){
                 EscherContainerRecord bstore = (EscherContainerRecord)r;
 
-                ByteArrayOutputStream b2 = new ByteArrayOutputStream();
+                UnsynchronizedByteArrayOutputStream b2 = new UnsynchronizedByteArrayOutputStream();
                 for (EscherRecord br : bstore) {
                     byte[] b = new byte[36+8];
                     br.serialize(0, b);
@@ -114,8 +117,7 @@ public final class PPDrawingGroup extends RecordAtom {
         out.write(dgghead);
 
         // Finally, write out the children
-        out.write(bout.toByteArray());
-
+        bout.writeTo(out);
     }
 
     public EscherContainerRecord getDggContainer(){
diff --git a/poi-scratchpad/src/main/java/org/apache/poi/hslf/record/PersistPtrHolder.java b/poi-scratchpad/src/main/java/org/apache/poi/hslf/record/PersistPtrHolder.java
index 1ee2403cf7..4e47cb7195 100644
--- a/poi-scratchpad/src/main/java/org/apache/poi/hslf/record/PersistPtrHolder.java
+++ b/poi-scratchpad/src/main/java/org/apache/poi/hslf/record/PersistPtrHolder.java
@@ -17,24 +17,23 @@
 
 package org.apache.poi.hslf.record;
 
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.OutputStream;
 import java.util.Arrays;
 import java.util.Collections;
+import java.util.Comparator;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.Map.Entry;
-import java.util.TreeMap;
 import java.util.function.Supplier;
 
 import org.apache.poi.hslf.exceptions.CorruptPowerPointFileException;
-import org.apache.poi.hslf.exceptions.HSLFException;
 import org.apache.poi.util.BitField;
 import org.apache.poi.util.BitFieldFactory;
 import org.apache.poi.util.GenericRecordUtil;
 import org.apache.poi.util.IOUtils;
 import org.apache.poi.util.LittleEndian;
+import org.apache.poi.util.LittleEndianConsts;
 
 /**
  * General holder for PersistPtrFullBlock and PersistPtrIncrementalBlock
@@ -54,14 +53,14 @@ public final class PersistPtrHolder extends PositionDependentRecordAtom
 
 	private final byte[] _header;
 	private byte[] _ptrData; // Will need to update this once we allow updates to _slideLocations
-	private long _type;
+	private final long _type;
 
 	/**
 	 * Holds the lookup for slides to their position on disk.
 	 * You always need to check the most recent PersistPtrHolder
 	 *  that knows about a given slide to find the right location
 	 */
-	private Map<Integer,Integer> _slideLocations;
+	private final Map<Integer,Integer> _slideLocations;
 
 	private static final BitField persistIdFld = BitFieldFactory.getInstance(0X000FFFFF);
 	private static final BitField cntPersistFld  = BitFieldFactory.getInstance(0XFFF00000);
@@ -185,51 +184,47 @@ public final class PersistPtrHolder extends PositionDependentRecordAtom
 	}
 
 	private void normalizePersistDirectory() {
-        TreeMap<Integer,Integer> orderedSlideLocations = new TreeMap<>(_slideLocations);
-
-        @SuppressWarnings("resource")
-        BufAccessBAOS bos = new BufAccessBAOS(); // NOSONAR
-        byte[] intbuf = new byte[4];
-        int lastPersistEntry = -1;
-        int lastSlideId = -1;
-        for (Entry<Integer,Integer> me : orderedSlideLocations.entrySet()) {
-            int nextSlideId = me.getKey();
-            int offset = me.getValue();
-            try {
-                // Building the info block
-                // First 20 bits = offset number = slide ID (persistIdFld, i.e. first slide ID of a continuous group)
-                // Remaining 12 bits = offset count = 1 (cntPersistFld, i.e. continuous entries in a group)
-
-                if (lastSlideId+1 == nextSlideId) {
-                    // use existing PersistDirectoryEntry, need to increase entry count
-                    assert(lastPersistEntry != -1);
-                    int infoBlock = LittleEndian.getInt(bos.getBuf(), lastPersistEntry);
-                    int entryCnt = cntPersistFld.getValue(infoBlock);
-                    infoBlock = cntPersistFld.setValue(infoBlock, entryCnt+1);
-                    LittleEndian.putInt(bos.getBuf(), lastPersistEntry, infoBlock);
-                } else {
-                    // start new PersistDirectoryEntry
-                    lastPersistEntry = bos.size();
-                    int infoBlock = persistIdFld.setValue(0, nextSlideId);
-                    infoBlock = cntPersistFld.setValue(infoBlock, 1);
-                    LittleEndian.putInt(intbuf, 0, infoBlock);
-                    bos.write(intbuf);
-                }
-                // Add to the ptrData offset lookup hash
-                LittleEndian.putInt(intbuf, 0, offset);
-                bos.write(intbuf);
-                lastSlideId = nextSlideId;
-            } catch (IOException e) {
-                // ByteArrayOutputStream is very unlikely throwing a IO exception (maybe because of OOM ...)
-                throw new HSLFException(e);
-            }
-        }
+		// Building the info block
+		// First 20 bits = offset number = slide ID (persistIdFld, i.e. first slide ID of a continuous group)
+		// Remaining 12 bits = offset count = 1 (cntPersistFld, i.e. continuous entries in a group)
+		//
+		// the info block is then followed by the slide offset (32 bits)
+
+		int[] infoBlocks = new int[_slideLocations.size()*2];
+		int lastSlideId = -1;
+		int lastPersistIdx = 0;
+		int lastIdx = -1;
+		int entryCnt = 0;
+		int baseSlideId = -1;
+
+		Iterable<Entry<Integer,Integer>> iter = _slideLocations.entrySet().stream()
+			.sorted(Comparator.comparingInt(Entry::getKey))::iterator;
+		for (Entry<Integer, Integer> me : iter) {
+			int nextSlideId = me.getKey();
+			if (lastSlideId + 1 < nextSlideId) {
+				// start new PersistDirectoryEntry
+				lastPersistIdx = ++lastIdx;
+				entryCnt = 0;
+				baseSlideId = nextSlideId;
+			}
+
+			int infoBlock = persistIdFld.setValue(0, baseSlideId);
+			infoBlock = cntPersistFld.setValue(infoBlock, ++entryCnt);
+			infoBlocks[lastPersistIdx] = infoBlock;
+			// add the offset
+			infoBlocks[++lastIdx] = me.getValue();
+
+			lastSlideId = nextSlideId;
+		}
 
-        // Save the new ptr data
-        _ptrData = bos.toByteArray();
+		// Save the new ptr data
+		_ptrData = new byte[(lastIdx+1)*LittleEndianConsts.INT_SIZE];
+		for (int idx = 0; idx<=lastIdx; idx++) {
+			LittleEndian.putInt(_ptrData, idx*LittleEndianConsts.INT_SIZE, infoBlocks[idx]);
+		}
 
-        // Update the atom header
-        LittleEndian.putInt(_header,4,bos.size());
+		// Update the atom header
+		LittleEndian.putInt(_header, 4, _ptrData.length);
 	}
 
 	/**
@@ -243,12 +238,6 @@ public final class PersistPtrHolder extends PositionDependentRecordAtom
 		out.write(_ptrData);
 	}
 
-    private static class BufAccessBAOS extends ByteArrayOutputStream {
-        public byte[] getBuf() {
-            return buf;
-        }
-    }
-
 	@Override
 	public Map<String, Supplier<?>> getGenericProperties() {
 		return GenericRecordUtil.getGenericProperties(
diff --git a/poi-scratchpad/src/main/java/org/apache/poi/hslf/record/RecordContainer.java b/poi-scratchpad/src/main/java/org/apache/poi/hslf/record/RecordContainer.java
index 635ad85b28..98e48067c2 100644
--- a/poi-scratchpad/src/main/java/org/apache/poi/hslf/record/RecordContainer.java
+++ b/poi-scratchpad/src/main/java/org/apache/poi/hslf/record/RecordContainer.java
@@ -17,7 +17,6 @@
 
 package org.apache.poi.hslf.record;
 
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.OutputStream;
 import java.util.ArrayList;
@@ -25,6 +24,7 @@ import java.util.Arrays;
 import java.util.Map;
 import java.util.function.Supplier;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.util.ArrayUtil;
 import org.apache.poi.util.LittleEndian;
 
@@ -226,8 +226,8 @@ public abstract class RecordContainer extends Record
 	 * @param out the stream to write to
 	 */
 	public void writeOut(byte headerA, byte headerB, long type, Record[] children, OutputStream out) throws IOException {
-		// Create a ByteArrayOutputStream to hold everything in
-		ByteArrayOutputStream baos = new ByteArrayOutputStream();
+		// Create a UnsynchronizedByteArrayOutputStream to hold everything in
+		UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
 
 		// Write out our header, less the size
 		baos.write(new byte[] {headerA,headerB});
diff --git a/poi-scratchpad/src/main/java/org/apache/poi/hslf/record/StyleTextPropAtom.java b/poi-scratchpad/src/main/java/org/apache/poi/hslf/record/StyleTextPropAtom.java
index de2b28c311..e758d57fce 100644
--- a/poi-scratchpad/src/main/java/org/apache/poi/hslf/record/StyleTextPropAtom.java
+++ b/poi-scratchpad/src/main/java/org/apache/poi/hslf/record/StyleTextPropAtom.java
@@ -17,7 +17,8 @@
 
 package org.apache.poi.hslf.record;
 
-import java.io.ByteArrayOutputStream;
+import static org.apache.logging.log4j.util.Unbox.box;
+
 import java.io.IOException;
 import java.io.OutputStream;
 import java.util.ArrayList;
@@ -26,6 +27,7 @@ import java.util.List;
 import java.util.Map;
 import java.util.function.Supplier;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.hslf.exceptions.HSLFException;
 import org.apache.poi.hslf.model.textproperties.TextPropCollection;
 import org.apache.poi.hslf.model.textproperties.TextPropCollection.TextPropType;
@@ -34,8 +36,6 @@ import org.apache.poi.util.HexDump;
 import org.apache.poi.util.IOUtils;
 import org.apache.poi.util.LittleEndian;
 
-import static org.apache.logging.log4j.util.Unbox.box;
-
 /**
  * A StyleTextPropAtom (type 4001). Holds basic character properties
  *  (bold, italic, underline, font size etc) and paragraph properties
@@ -55,7 +55,7 @@ public final class StyleTextPropAtom extends RecordAtom {
     //arbitrarily selected; may need to increase
     private static final int MAX_RECORD_LENGTH = 1_000_000;
 
-    private byte[] _header;
+    private final byte[] _header;
     private byte[] reserved;
 
     private byte[] rawContents; // Holds the contents between write-outs
@@ -312,7 +312,7 @@ public final class StyleTextPropAtom extends RecordAtom {
             // Only update the style bytes, if the styles have been potentially
             // changed
 
-            ByteArrayOutputStream baos = new ByteArrayOutputStream();
+            UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
 
             // First up, we need to serialise the paragraph properties
             for(TextPropCollection tpc : paragraphStyles) {
diff --git a/poi-scratchpad/src/main/java/org/apache/poi/hslf/record/TextRulerAtom.java b/poi-scratchpad/src/main/java/org/apache/poi/hslf/record/TextRulerAtom.java
index 5de317cc0c..a9b083b236 100644
--- a/poi-scratchpad/src/main/java/org/apache/poi/hslf/record/TextRulerAtom.java
+++ b/poi-scratchpad/src/main/java/org/apache/poi/hslf/record/TextRulerAtom.java
@@ -19,7 +19,6 @@ package org.apache.poi.hslf.record;
 
 import static org.apache.poi.util.BitFieldFactory.getInstance;
 
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.OutputStream;
 import java.util.ArrayList;
@@ -28,6 +27,7 @@ import java.util.List;
 import java.util.Map;
 import java.util.function.Supplier;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.hslf.model.textproperties.HSLFTabStop;
 import org.apache.poi.hslf.model.textproperties.HSLFTabStopPropCollection;
 import org.apache.poi.util.BitField;
@@ -120,7 +120,7 @@ public final class TextRulerAtom extends RecordAtom {
      */
     @Override
     public void writeOut(final OutputStream out) throws IOException {
-        final ByteArrayOutputStream bos = new ByteArrayOutputStream(200);
+        final UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream(200);
         final LittleEndianOutputStream lbos = new LittleEndianOutputStream(bos);
         int mask = 0;
         mask |= writeIf(lbos, numLevels, C_LEVELS);
diff --git a/poi-scratchpad/src/main/java/org/apache/poi/hslf/record/TextSpecInfoAtom.java b/poi-scratchpad/src/main/java/org/apache/poi/hslf/record/TextSpecInfoAtom.java
index fdc16db465..1071422e3b 100644
--- a/poi-scratchpad/src/main/java/org/apache/poi/hslf/record/TextSpecInfoAtom.java
+++ b/poi-scratchpad/src/main/java/org/apache/poi/hslf/record/TextSpecInfoAtom.java
@@ -17,7 +17,6 @@
 
 package org.apache.poi.hslf.record;
 
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.OutputStream;
 import java.util.ArrayList;
@@ -26,6 +25,7 @@ import java.util.List;
 import java.util.Map;
 import java.util.function.Supplier;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.hslf.exceptions.HSLFException;
 import org.apache.poi.util.GenericRecordUtil;
 import org.apache.poi.util.IOUtils;
@@ -46,7 +46,7 @@ public final class TextSpecInfoAtom extends RecordAtom {
     /**
      * Record header.
      */
-    private byte[] _header;
+    private final byte[] _header;
 
     /**
      * Record data.
@@ -112,7 +112,7 @@ public final class TextSpecInfoAtom extends RecordAtom {
      */
     public void reset(int size){
         TextSpecInfoRun sir = new TextSpecInfoRun(size);
-        ByteArrayOutputStream bos = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream();
         try {
             sir.writeOut(bos);
         } catch (IOException e) {
@@ -127,13 +127,11 @@ public final class TextSpecInfoAtom extends RecordAtom {
     /**
      * Adapts the size by enlarging the last {@link TextSpecInfoRun}
      * or chopping the runs to the given length
-     *
-     * @param size
      */
     public void setParentSize(int size) {
         assert(size > 0);
         int covered = 0;
-        ByteArrayOutputStream bos = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream();
         TextSpecInfoRun[] runs = getTextSpecInfoRuns();
         assert(runs.length > 0);
         for (int i=0; i<runs.length && covered < size; i++) {
diff --git a/poi-scratchpad/src/main/java/org/apache/poi/hslf/record/TxMasterStyleAtom.java b/poi-scratchpad/src/main/java/org/apache/poi/hslf/record/TxMasterStyleAtom.java
index a396cd95bf..ee419faf31 100644
--- a/poi-scratchpad/src/main/java/org/apache/poi/hslf/record/TxMasterStyleAtom.java
+++ b/poi-scratchpad/src/main/java/org/apache/poi/hslf/record/TxMasterStyleAtom.java
@@ -17,7 +17,6 @@
 
 package org.apache.poi.hslf.record;
 
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.OutputStream;
 import java.util.ArrayList;
@@ -26,6 +25,7 @@ import java.util.List;
 import java.util.Map;
 import java.util.function.Supplier;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.poi.hslf.exceptions.HSLFException;
@@ -64,7 +64,7 @@ public final class TxMasterStyleAtom extends RecordAtom {
 
     private static final long _type = RecordTypes.TxMasterStyleAtom.typeID;
 
-    private byte[] _header;
+    private final byte[] _header;
     private byte[] _data;
 
     private List<TextPropCollection> paragraphStyles;
@@ -89,6 +89,7 @@ public final class TxMasterStyleAtom extends RecordAtom {
      * @return type of this record
      * @see RecordTypes#TxMasterStyleAtom
      */
+    @Override
     public long getRecordType() {
         return _type;
     }
@@ -97,6 +98,7 @@ public final class TxMasterStyleAtom extends RecordAtom {
      * Write the contents of the record back, so it can be written
      *  to disk
      */
+    @Override
     public void writeOut(OutputStream out) throws IOException {
         // Write out the (new) header
         out.write(_header);
@@ -126,7 +128,7 @@ public final class TxMasterStyleAtom extends RecordAtom {
 
     /**
      * Return type of the text.
-     * Must be a constant defined in <code>TextHeaderAtom</code>
+     * Must be a constant defined in {@code TextHeaderAtom}
      *
      * @return type of the text
      * @see TextHeaderAtom
@@ -187,7 +189,7 @@ public final class TxMasterStyleAtom extends RecordAtom {
         int type = getTextType();
 
         try {
-            ByteArrayOutputStream bos = new ByteArrayOutputStream();
+            UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream();
             LittleEndianOutputStream leos = new LittleEndianOutputStream(bos);
             int levels = paragraphStyles.size();
             leos.writeShort(levels);
diff --git a/poi-scratchpad/src/main/java/org/apache/poi/hslf/usermodel/HSLFObjectData.java b/poi-scratchpad/src/main/java/org/apache/poi/hslf/usermodel/HSLFObjectData.java
index 60f864188d..3bc921dc96 100644
--- a/poi-scratchpad/src/main/java/org/apache/poi/hslf/usermodel/HSLFObjectData.java
+++ b/poi-scratchpad/src/main/java/org/apache/poi/hslf/usermodel/HSLFObjectData.java
@@ -16,7 +16,6 @@
 ==================================================================== */
 package org.apache.poi.hslf.usermodel;
 
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
@@ -25,8 +24,7 @@ import java.util.List;
 import java.util.Map;
 import java.util.function.Supplier;
 
-import org.apache.logging.log4j.LogManager;
-import org.apache.logging.log4j.Logger;
+import org.apache.commons.io.output.ByteArrayOutputStream;
 import org.apache.poi.common.usermodel.GenericRecord;
 import org.apache.poi.hslf.record.ExOleObjStg;
 import org.apache.poi.sl.usermodel.ObjectData;
@@ -35,12 +33,10 @@ import org.apache.poi.sl.usermodel.ObjectData;
  * A class that represents object data embedded in a slide show.
  */
 public class HSLFObjectData implements ObjectData, GenericRecord {
-    private static final Logger LOG = LogManager.getLogger(HSLFObjectData.class);
-
     /**
      * The record that contains the object data.
      */
-    private ExOleObjStg storage;
+    private final ExOleObjStg storage;
 
     /**
      * Creates the object data wrapping the record that contains the object data.
@@ -55,10 +51,12 @@ public class HSLFObjectData implements ObjectData, GenericRecord {
     public InputStream getInputStream() {
         return storage.getData();
     }
-    
+
     @Override
-    public OutputStream getOutputStream() throws IOException {
-        return new ByteArrayOutputStream(100000) {
+    public OutputStream getOutputStream() {
+        // can't use UnsynchronizedByteArrayOutputStream here, because it's final
+        return new ByteArrayOutputStream() {
+            @Override
             public void close() throws IOException {
                 setData(getBytes());
             }
@@ -71,7 +69,7 @@ public class HSLFObjectData implements ObjectData, GenericRecord {
      * @param data the embedded data.
      */
      public void setData(byte[] data) throws IOException {
-        storage.setData(data);    
+        storage.setData(data);
     }
 
     /**
diff --git a/poi-scratchpad/src/main/java/org/apache/poi/hslf/usermodel/HSLFObjectShape.java b/poi-scratchpad/src/main/java/org/apache/poi/hslf/usermodel/HSLFObjectShape.java
index 344e038374..a5414672b9 100644
--- a/poi-scratchpad/src/main/java/org/apache/poi/hslf/usermodel/HSLFObjectShape.java
+++ b/poi-scratchpad/src/main/java/org/apache/poi/hslf/usermodel/HSLFObjectShape.java
@@ -17,11 +17,12 @@
 
 package org.apache.poi.hslf.usermodel;
 
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
+import java.io.InputStream;
 import java.io.OutputStream;
 
+import org.apache.commons.io.output.AbstractByteArrayOutputStream;
+import org.apache.commons.io.output.ByteArrayOutputStream;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.poi.ddf.EscherContainerRecord;
@@ -51,7 +52,7 @@ public final class HSLFObjectShape extends HSLFPictureShape implements ObjectSha
     private ExEmbed _exEmbed;
 
     /**
-     * Create a new <code>OLEShape</code>
+     * Create a new {@code OLEShape}
      *
     * @param data the picture data
      */
@@ -60,7 +61,7 @@ public final class HSLFObjectShape extends HSLFPictureShape implements ObjectSha
     }
 
     /**
-     * Create a new <code>OLEShape</code>
+     * Create a new {@code OLEShape}
      *
      * @param data the picture data
      * @param parent the parent shape
@@ -70,10 +71,10 @@ public final class HSLFObjectShape extends HSLFPictureShape implements ObjectSha
     }
 
     /**
-      * Create a <code>OLEShape</code> object
+      * Create a {@code OLEShape} object
       *
-      * @param escherRecord the <code>EscherSpContainer</code> record which holds information about
-      *        this picture in the <code>Slide</code>
+      * @param escherRecord the {@code EscherSpContainer} record which holds information about
+      *        this picture in the {@code Slide}
       * @param parent the parent shape of this picture
       */
     public HSLFObjectShape(EscherContainerRecord escherRecord, ShapeContainer<HSLFShape,HSLFTextParagraph> parent){
@@ -100,7 +101,11 @@ public final class HSLFObjectShape extends HSLFPictureShape implements ObjectSha
 
     	EscherContainerRecord ecr = getSpContainer();
     	EscherSpRecord spRecord = ecr.getChildById(EscherSpRecord.RECORD_ID);
-        spRecord.setFlags(spRecord.getFlags()|EscherSpRecord.FLAG_OLESHAPE);
+    	if (spRecord != null) {
+            spRecord.setFlags(spRecord.getFlags() | EscherSpRecord.FLAG_OLESHAPE);
+        } else {
+    	    LOG.atWarn().log("Ole shape record not found.");
+        }
 
         HSLFEscherClientDataRecord cldata = getClientData(true);
         ExObjRefAtom uer = null;
@@ -123,6 +128,7 @@ public final class HSLFObjectShape extends HSLFPictureShape implements ObjectSha
      *
      * @return the unique identifier for the OLE object
      */
+    @Override
     public HSLFObjectData getObjectData(){
         HSLFSlideShow ppt = getSheet().getSlideShow();
         HSLFObjectData[] ole = ppt.getEmbeddedObjects();
@@ -184,7 +190,7 @@ public final class HSLFObjectShape extends HSLFPictureShape implements ObjectSha
                     }
                 }
             }
-            
+
             if (_exEmbed == null && create) {
                 _exEmbed = new ExEmbed();
                 _exEmbed.getExOleObjAtom().setObjID(id);
@@ -193,8 +199,8 @@ public final class HSLFObjectShape extends HSLFPictureShape implements ObjectSha
         }
         return _exEmbed;
     }
-    
-    
+
+
     /**
      * Returns the instance name of the embedded object, e.g. "Document" or "Workbook".
      *
@@ -231,45 +237,51 @@ public final class HSLFObjectShape extends HSLFPictureShape implements ObjectSha
         }
     }
 
-    public OutputStream updateObjectData(final Application application, final ObjectMetaData metaData) throws IOException {
+    @Override
+    public OutputStream updateObjectData(final Application application, final ObjectMetaData metaData) {
         final ObjectMetaData md = (application != null) ? application.getMetaData() : metaData;
         if (md == null) {
             throw new RuntimeException("either application or metaData needs to be set");
         }
 
-        return new ByteArrayOutputStream(100000) {
+        // can't use UnsynchronizedByteArrayOutputStream here, because it's final
+        return new ByteArrayOutputStream() {
+            @Override
             public void close() throws IOException {
-                final FileMagic fm = FileMagic.valueOf(this.buf);
-                final ByteArrayInputStream bis = new ByteArrayInputStream(this.buf, 0, this.count);
-                final HSLFSlideShow ppt = getSheet().getSlideShow();
-
-                try (POIFSFileSystem poifs = (fm == FileMagic.OLE2) ? new POIFSFileSystem(bis) : new POIFSFileSystem()) {
-                    if (fm != FileMagic.OLE2) {
-                        poifs.createDocument(bis, md.getOleEntry());
-                    }
+                addUpdatedData(md,this);
+            }
+        };
+    }
 
-                    Ole10Native.createOleMarkerEntry(poifs);
-
-                    poifs.getRoot().setStorageClsid(md.getClassID());
-
-                    int oid = getObjectID();
-                    if (oid == 0) {
-                        // assign new embedding
-                        oid = ppt.addEmbed(poifs);
-                        setObjectID(oid);
-                    } else {
-                        final HSLFObjectData od = getObjectData();
-                        if (od != null) {
-                            ByteArrayOutputStream bos = new ByteArrayOutputStream(this.size()+1000);
-                            poifs.writeFilesystem(bos);
-                            od.setData(bos.toByteArray());
-                        }
+    private void addUpdatedData(ObjectMetaData md, AbstractByteArrayOutputStream baos) throws IOException {
+        try (InputStream bis = FileMagic.prepareToCheckMagic(baos.toInputStream())) {
+            final FileMagic fm = FileMagic.valueOf(bis);
+            try (POIFSFileSystem poifs = (fm == FileMagic.OLE2) ? new POIFSFileSystem(bis) : new POIFSFileSystem()) {
+                if (fm != FileMagic.OLE2) {
+                    poifs.createDocument(bis, md.getOleEntry());
+                }
+                baos.reset();
+
+                Ole10Native.createOleMarkerEntry(poifs);
+
+                poifs.getRoot().setStorageClsid(md.getClassID());
+
+                int oid = getObjectID();
+                if (oid == 0) {
+                    // assign new embedding
+                    oid = getSheet().getSlideShow().addEmbed(poifs);
+                    setObjectID(oid);
+                } else {
+                    final HSLFObjectData od = getObjectData();
+                    if (od != null) {
+                        poifs.writeFilesystem(baos);
+                        od.setData(baos.toByteArray());
                     }
-
-                    setProgId(md.getProgId());
-                    setFullName(md.getObjectName());
                 }
+
+                setProgId(md.getProgId());
+                setFullName(md.getObjectName());
             }
-        };
+        }
     }
 }
diff --git a/poi-scratchpad/src/main/java/org/apache/poi/hslf/usermodel/HSLFSlideShow.java b/poi-scratchpad/src/main/java/org/apache/poi/hslf/usermodel/HSLFSlideShow.java
index 5e2e5d9ebc..e2a3b51155 100644
--- a/poi-scratchpad/src/main/java/org/apache/poi/hslf/usermodel/HSLFSlideShow.java
+++ b/poi-scratchpad/src/main/java/org/apache/poi/hslf/usermodel/HSLFSlideShow.java
@@ -17,8 +17,9 @@
 
 package org.apache.poi.hslf.usermodel;
 
+import static org.apache.logging.log4j.util.Unbox.box;
+
 import java.awt.Dimension;
-import java.io.ByteArrayOutputStream;
 import java.io.Closeable;
 import java.io.File;
 import java.io.FileInputStream;
@@ -33,6 +34,7 @@ import java.util.List;
 import java.util.Map;
 import java.util.function.Supplier;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.poi.POIDocument;
@@ -66,8 +68,6 @@ import org.apache.poi.util.IOUtils;
 import org.apache.poi.util.Internal;
 import org.apache.poi.util.Units;
 
-import static org.apache.logging.log4j.util.Unbox.box;
-
 /**
  * This class is a friendly wrapper on top of the more scary HSLFSlideShow.
  *
@@ -708,9 +708,9 @@ public final class HSLFSlideShow extends POIDocument implements SlideShow<HSLFSh
 	}
 
 	/**
-	 * Create a blank <code>Slide</code>.
+	 * Create a blank {@code Slide}.
 	 *
-	 * @return the created <code>Slide</code>
+	 * @return the created {@code Slide}
 	 */
 	@Override
 	public HSLFSlide createSlide() {
@@ -882,6 +882,7 @@ public final class HSLFSlideShow extends POIDocument implements SlideShow<HSLFSh
 	 *
 	 * @since POI 4.1.0
 	 */
+	@Override
 	public HSLFFontInfo addFont(InputStream fontData) throws IOException {
 		Document doc = getDocumentRecord();
 		doc.getDocumentAtom().setSaveWithFonts(true);
@@ -893,7 +894,7 @@ public final class HSLFSlideShow extends POIDocument implements SlideShow<HSLFSh
 	 *
 	 * @param idx
 	 *            0-based index of the font
-	 * @return of an instance of <code>PPFont</code> or <code>null</code> if not
+	 * @return of an instance of {@code PPFont} or {@code null} if not
 	 *         found
 	 */
 	public HSLFFontInfo getFont(int idx) {
@@ -1040,7 +1041,7 @@ public final class HSLFSlideShow extends POIDocument implements SlideShow<HSLFSh
         ExOleObjStg exOleObjStg = new ExOleObjStg();
         try {
             Ole10Native.createOleMarkerEntry(poiData);
-	        ByteArrayOutputStream bos = new ByteArrayOutputStream();
+	        UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream();
 	        poiData.writeFilesystem(bos);
 	        exOleObjStg.setData(bos.toByteArray());
         } catch (IOException e) {
@@ -1246,7 +1247,7 @@ public final class HSLFSlideShow extends POIDocument implements SlideShow<HSLFSh
 	}
 
 	@Override
-	public EncryptionInfo getEncryptionInfo() throws IOException {
+	public EncryptionInfo getEncryptionInfo() {
 		return getSlideShowImpl().getEncryptionInfo();
 	}
 
diff --git a/poi-scratchpad/src/main/java/org/apache/poi/hslf/usermodel/HSLFSlideShowImpl.java b/poi-scratchpad/src/main/java/org/apache/poi/hslf/usermodel/HSLFSlideShowImpl.java
index f697e859ce..62a9d997b1 100644
--- a/poi-scratchpad/src/main/java/org/apache/poi/hslf/usermodel/HSLFSlideShowImpl.java
+++ b/poi-scratchpad/src/main/java/org/apache/poi/hslf/usermodel/HSLFSlideShowImpl.java
@@ -23,17 +23,18 @@ import static org.apache.poi.hslf.usermodel.HSLFSlideShow.PP95_DOCUMENT;
 import static org.apache.poi.hslf.usermodel.HSLFSlideShow.PP97_DOCUMENT;
 
 import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.Closeable;
 import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
+import java.io.SequenceInputStream;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.Comparator;
+import java.util.Enumeration;
 import java.util.HashMap;
 import java.util.Iterator;
 import java.util.LinkedList;
@@ -44,6 +45,8 @@ import java.util.Objects;
 import java.util.TreeMap;
 import java.util.stream.Collectors;
 
+import org.apache.commons.collections4.IteratorUtils;
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.poi.POIDocument;
@@ -659,7 +662,7 @@ public final class HSLFSlideShowImpl extends POIDocument implements Closeable {
     /**
      * Writes out the slideshow to the currently open file.
      * <p>
-     * <p>This will fail (with an {@link IllegalStateException} if the
+     * This will fail (with an {@link IllegalStateException} if the
      * slideshow was opened read-only, opened from an {@link InputStream}
      * instead of a File, or if this is not the root document. For those cases,
      * you must use {@link #write(OutputStream)} or {@link #write(File)} to
@@ -686,7 +689,7 @@ public final class HSLFSlideShowImpl extends POIDocument implements Closeable {
      * of this class.
      * <p>This will write out only the common OLE2 streams. If you require all
      * streams to be written out, use {@link #write(File, boolean)}
-     * with <code>preserveNodes</code> set to <code>true</code>.
+     * with {@code preserveNodes} set to {@code true}.
      *
      * @param newFile The File to write to.
      * @throws IOException If there is an unexpected IOException from writing to the File
@@ -701,7 +704,7 @@ public final class HSLFSlideShowImpl extends POIDocument implements Closeable {
      * Writes out the slideshow file the is represented by an instance
      * of this class.
      * If you require all streams to be written out (eg Marcos, embeded
-     * documents), then set <code>preserveNodes</code> set to <code>true</code>
+     * documents), then set {@code preserveNodes} set to {@code true}
      *
      * @param newFile       The File to write to.
      * @param preserveNodes Should all OLE2 streams be written back out, or only the common ones?
@@ -724,7 +727,7 @@ public final class HSLFSlideShowImpl extends POIDocument implements Closeable {
      * of this class.
      * <p>This will write out only the common OLE2 streams. If you require all
      * streams to be written out, use {@link #write(OutputStream, boolean)}
-     * with <code>preserveNodes</code> set to <code>true</code>.
+     * with {@code preserveNodes} set to {@code true}.
      *
      * @param out The OutputStream to write to.
      * @throws IOException If there is an unexpected IOException from
@@ -740,7 +743,7 @@ public final class HSLFSlideShowImpl extends POIDocument implements Closeable {
      * Writes out the slideshow file the is represented by an instance
      * of this class.
      * If you require all streams to be written out (eg Marcos, embeded
-     * documents), then set <code>preserveNodes</code> set to <code>true</code>
+     * documents), then set {@code preserveNodes} set to {@code true}
      *
      * @param out           The OutputStream to write to.
      * @param preserveNodes Should all OLE2 streams be written back out, or only the common ones?
@@ -776,16 +779,16 @@ public final class HSLFSlideShowImpl extends POIDocument implements Closeable {
             // Write out the Property Streams
             writeProperties(outFS, writtenEntries);
 
-            BufAccessBAOS baos = new BufAccessBAOS();
+            try (UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream()) {
 
-            // For position dependent records, hold where they were and now are
-            // As we go along, update, and hand over, to any Position Dependent
-            // records we happen across
-            updateAndWriteDependantRecords(baos, null);
+                // For position dependent records, hold where they were and now are
+                // As we go along, update, and hand over, to any Position Dependent
+                // records we happen across
+                updateAndWriteDependantRecords(baos, null);
 
-            // Update our cached copy of the bytes that make up the PPT stream
-            _docstream = baos.toByteArray();
-            baos.close();
+                // Update our cached copy of the bytes that make up the PPT stream
+                _docstream = baos.toByteArray();
+            }
 
             // Write the PPT stream into the POIFS layer
             ByteArrayInputStream bais = new ByteArrayInputStream(_docstream);
@@ -796,20 +799,18 @@ public final class HSLFSlideShowImpl extends POIDocument implements Closeable {
             currentUser.writeToFS(outFS);
             writtenEntries.add("Current User");
 
-            if (_pictures.size() > 0) {
-                BufAccessBAOS pict = new BufAccessBAOS();
-                for (HSLFPictureData p : _pictures) {
-                    int offset = pict.size();
-                    p.write(pict);
-                    encryptedSS.encryptPicture(pict.getBuf(), offset);
-                }
-                outFS.createOrUpdateDocument(
-                    new ByteArrayInputStream(pict.getBuf(), 0, pict.size()), "Pictures"
+            if (!_pictures.isEmpty()) {
+                Enumeration<InputStream> pictEnum = IteratorUtils.asEnumeration(
+                    _pictures.stream().map(data -> encryptOnePicture(encryptedSS, data)).iterator()
                 );
-                writtenEntries.add("Pictures");
-                pict.close();
-            }
 
+                try (SequenceInputStream sis = new SequenceInputStream(pictEnum)) {
+                    outFS.createOrUpdateDocument(sis, "Pictures");
+                    writtenEntries.add("Pictures");
+                } catch (IllegalStateException e) {
+                    throw (IOException)e.getCause();
+                }
+            }
         }
 
         // If requested, copy over any other streams we spot, eg Macros
@@ -818,6 +819,17 @@ public final class HSLFSlideShowImpl extends POIDocument implements Closeable {
         }
     }
 
+    private static InputStream encryptOnePicture(HSLFSlideShowEncrypted encryptedSS, HSLFPictureData data) {
+        try (UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream()) {
+            data.write(baos);
+            byte[] pictBytes = baos.toByteArray();
+            encryptedSS.encryptPicture(pictBytes, 0);
+            return new ByteArrayInputStream(pictBytes);
+        } catch (IOException e) {
+            throw new IllegalStateException(e);
+        }
+    }
+
 
     @Override
     public EncryptionInfo getEncryptionInfo() {
@@ -1017,12 +1029,6 @@ public final class HSLFSlideShowImpl extends POIDocument implements Closeable {
         super.replaceDirectory(newDirectory);
     }
 
-    private static class BufAccessBAOS extends ByteArrayOutputStream {
-        public byte[] getBuf() {
-            return buf;
-        }
-    }
-
     private static class CountingOS extends OutputStream {
         int count;
 
diff --git a/poi-scratchpad/src/main/java/org/apache/poi/hsmf/datatypes/PropertiesChunk.java b/poi-scratchpad/src/main/java/org/apache/poi/hsmf/datatypes/PropertiesChunk.java
index 6cf92111a6..7915ca5c66 100644
--- a/poi-scratchpad/src/main/java/org/apache/poi/hsmf/datatypes/PropertiesChunk.java
+++ b/poi-scratchpad/src/main/java/org/apache/poi/hsmf/datatypes/PropertiesChunk.java
@@ -17,8 +17,9 @@
 
 package org.apache.poi.hsmf.datatypes;
 
+import static org.apache.logging.log4j.util.Unbox.box;
+
 import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
@@ -30,6 +31,7 @@ import java.util.Locale;
 import java.util.Map;
 import java.util.Map.Entry;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.poi.hsmf.datatypes.PropertyValue.BooleanPropertyValue;
@@ -47,8 +49,6 @@ import org.apache.poi.util.IOUtils;
 import org.apache.poi.util.LittleEndian;
 import org.apache.poi.util.LittleEndian.BufferUnderrunException;
 
-import static org.apache.logging.log4j.util.Unbox.box;
-
 /**
  * <p>
  * A Chunk which holds (single) fixed-length properties, and pointer to the
@@ -76,13 +76,13 @@ public abstract class PropertiesChunk extends Chunk {
      * Holds properties, indexed by type. If a property is multi-valued, or
      * variable length, it will be held via a {@link ChunkBasedPropertyValue}.
      */
-    private Map<MAPIProperty, PropertyValue> properties = new HashMap<>();
+    private final Map<MAPIProperty, PropertyValue> properties = new HashMap<>();
 
     /**
      * The ChunkGroup that these properties apply to. Used when matching chunks
      * to variable sized and multi-valued properties
      */
-    private ChunkGroup parentGroup;
+    private final ChunkGroup parentGroup;
 
     /**
      * Creates a Properties Chunk.
@@ -254,7 +254,7 @@ public abstract class PropertiesChunk extends Chunk {
                 }
 
                 // Wrap and store
-                PropertyValue propVal = null;
+                PropertyValue propVal;
                 if (isPointer) {
                     // We'll match up the chunk later
                     propVal = new ChunkBasedPropertyValue(prop, flags, data, type);
@@ -302,16 +302,17 @@ public abstract class PropertiesChunk extends Chunk {
      *         If an I/O error occurs.
      */
     public void writeProperties(DirectoryEntry directory) throws IOException {
-        ByteArrayOutputStream baos = new ByteArrayOutputStream();
-        List<PropertyValue> values = writeProperties(baos);
-        baos.close();
+        try (UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream()) {
+            List<PropertyValue> values = writeProperties(baos);
 
-        // write the header data with the properties declaration
-        directory.createDocument(PropertiesChunk.NAME,
-            new ByteArrayInputStream(baos.toByteArray()));
+            // write the header data with the properties declaration
+            try (InputStream is = baos.toInputStream()) {
+                directory.createDocument(PropertiesChunk.NAME, is);
+            }
 
-        // write the property values
-        writeNodeData(directory, values);
+            // write the property values
+            writeNodeData(directory, values);
+        }
     }
 
     /**
diff --git a/poi-scratchpad/src/main/java/org/apache/poi/hwmf/record/HwmfEscape.java b/poi-scratchpad/src/main/java/org/apache/poi/hwmf/record/HwmfEscape.java
index 82baf52036..c56ae3f17f 100644
--- a/poi-scratchpad/src/main/java/org/apache/poi/hwmf/record/HwmfEscape.java
+++ b/poi-scratchpad/src/main/java/org/apache/poi/hwmf/record/HwmfEscape.java
@@ -190,7 +190,7 @@ public class HwmfEscape implements HwmfRecord {
     }
 
     public interface HwmfEscapeData {
-        public int init(LittleEndianInputStream leis, long recordSize, EscapeFunction escapeFunction) throws IOException;
+        int init(LittleEndianInputStream leis, long recordSize, EscapeFunction escapeFunction) throws IOException;
     }
 
 
diff --git a/poi-scratchpad/src/main/java/org/apache/poi/hwmf/usermodel/HwmfEmbeddedIterator.java b/poi-scratchpad/src/main/java/org/apache/poi/hwmf/usermodel/HwmfEmbeddedIterator.java
index 19fda80509..fb24af7cb4 100644
--- a/poi-scratchpad/src/main/java/org/apache/poi/hwmf/usermodel/HwmfEmbeddedIterator.java
+++ b/poi-scratchpad/src/main/java/org/apache/poi/hwmf/usermodel/HwmfEmbeddedIterator.java
@@ -17,13 +17,13 @@
 
 package org.apache.poi.hwmf.usermodel;
 
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.util.ArrayDeque;
 import java.util.Deque;
 import java.util.Iterator;
 import java.util.NoSuchElementException;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.hwmf.record.HwmfEscape;
 import org.apache.poi.hwmf.record.HwmfEscape.EscapeFunction;
 import org.apache.poi.hwmf.record.HwmfEscape.WmfEscapeEMF;
@@ -120,7 +120,7 @@ public class HwmfEmbeddedIterator implements Iterator<HwmfEmbedded> {
         final HwmfEmbedded emb = new HwmfEmbedded();
         emb.setEmbeddedType(HwmfEmbeddedType.EMF);
 
-        ByteArrayOutputStream bos = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream();
         try {
             for (;;) {
                 bos.write(img.getEmfData());
@@ -132,8 +132,8 @@ public class HwmfEmbeddedIterator implements Iterator<HwmfEmbedded> {
                     return emb;
                 }
             }
-        } catch (IOException e) {
-            // ByteArrayOutputStream doesn't throw IOException
+        } catch (IOException ignored) {
+            // UnsynchronizedByteArrayOutputStream doesn't throw IOException
             return null;
         } finally {
             emb.setData(bos.toByteArray());
diff --git a/poi-scratchpad/src/main/java/org/apache/poi/hwpf/dev/HWPFLister.java b/poi-scratchpad/src/main/java/org/apache/poi/hwpf/dev/HWPFLister.java
index 8fb9055bc5..71079c3b1b 100644
--- a/poi-scratchpad/src/main/java/org/apache/poi/hwpf/dev/HWPFLister.java
+++ b/poi-scratchpad/src/main/java/org/apache/poi/hwpf/dev/HWPFLister.java
@@ -17,8 +17,6 @@
 
 package org.apache.poi.hwpf.dev;
 
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.IOException;
@@ -31,6 +29,7 @@ import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.hwpf.HWPFDocument;
 import org.apache.poi.hwpf.HWPFDocumentCore;
 import org.apache.poi.hwpf.HWPFOldDocument;
@@ -262,12 +261,11 @@ public final class HWPFLister {
 
     private static HWPFDocumentCore writeOutAndReadBack(
             HWPFDocumentCore original ) {
-        try {
-            ByteArrayOutputStream baos = new ByteArrayOutputStream( 4096 );
+        try (UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream()) {
             original.write( baos );
-            ByteArrayInputStream bais = new ByteArrayInputStream(
-                    baos.toByteArray() );
-            return loadDoc( bais );
+            try (InputStream is = baos.toInputStream()) {
+                return loadDoc(is);
+            }
         }
         catch ( IOException e ) {
             throw new RuntimeException( e );
@@ -388,7 +386,7 @@ public final class HWPFLister {
         }
     }
 
-    public void dumpFileSystem() throws Exception {
+    public void dumpFileSystem() {
         System.out.println( dumpFileSystem( _doc.getDirectory() ) );
     }
 
@@ -439,8 +437,7 @@ public final class HWPFLister {
         }
     }
 
-    public void dumpPapx( boolean withProperties, boolean withSprms )
-            throws Exception {
+    public void dumpPapx( boolean withProperties, boolean withSprms ) {
         if ( _doc instanceof HWPFDocument ) {
             System.out.println( "binary PAP pages " );
 
@@ -514,8 +511,8 @@ public final class HWPFLister {
             if ( dumpAssotiatedPapx ) {
                 boolean hasAssotiatedPapx = false;
                 for ( PAPX papx : _doc.getParagraphTable().getParagraphs() ) {
-                    if ( papx.getStart() <= endOfParagraphCharOffset.intValue()
-                            && endOfParagraphCharOffset.intValue() < papx
+                    if ( papx.getStart() <= endOfParagraphCharOffset
+                            && endOfParagraphCharOffset < papx
                                     .getEnd() ) {
                         hasAssotiatedPapx = true;
                         System.out.println( "* " + papx );
diff --git a/poi-scratchpad/src/main/java/org/apache/poi/hwpf/usermodel/Picture.java b/poi-scratchpad/src/main/java/org/apache/poi/hwpf/usermodel/Picture.java
index 913b4950ae..d4283a612b 100644
--- a/poi-scratchpad/src/main/java/org/apache/poi/hwpf/usermodel/Picture.java
+++ b/poi-scratchpad/src/main/java/org/apache/poi/hwpf/usermodel/Picture.java
@@ -18,13 +18,13 @@
 package org.apache.poi.hwpf.usermodel;
 
 import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.OutputStream;
 import java.util.Collections;
 import java.util.List;
 import java.util.zip.InflaterInputStream;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.poi.ddf.EscherBSERecord;
@@ -37,6 +37,7 @@ import org.apache.poi.ddf.EscherRecord;
 import org.apache.poi.hwpf.model.PICF;
 import org.apache.poi.hwpf.model.PICFAndOfficeArtData;
 import org.apache.poi.sl.image.ImageHeaderPNG;
+import org.apache.poi.util.IOUtils;
 import org.apache.poi.util.StringUtil;
 
 /**
@@ -120,10 +121,10 @@ public final class Picture {
         }
     }
 
-    private void fillImageContent()
-    {
-        if ( content != null && content.length > 0 )
+    private void fillImageContent() {
+        if ( content != null && content.length > 0 ) {
             return;
+        }
 
         byte[] rawContent = getRawContent();
 
@@ -134,33 +135,21 @@ public final class Picture {
          * similarity in the data block contents.
          */
         if ( matchSignature( rawContent, COMPRESSED1, 32 )
-                || matchSignature( rawContent, COMPRESSED2, 32 ) )
-        {
-            try
-            {
-                InflaterInputStream in = new InflaterInputStream(
-                        new ByteArrayInputStream( rawContent, 33,
-                                rawContent.length - 33 ) );
-                ByteArrayOutputStream out = new ByteArrayOutputStream();
-                byte[] buf = new byte[4096];
-                int readBytes;
-                while ( ( readBytes = in.read( buf ) ) > 0 )
-                {
-                    out.write( buf, 0, readBytes );
-                }
+                || matchSignature( rawContent, COMPRESSED2, 32 ) ) {
+            try (ByteArrayInputStream bis = new ByteArrayInputStream( rawContent, 33, rawContent.length - 33 );
+                InflaterInputStream in = new InflaterInputStream(bis);
+                 UnsynchronizedByteArrayOutputStream out = new UnsynchronizedByteArrayOutputStream()) {
+
+                IOUtils.copy(in, out);
                 content = out.toByteArray();
-            }
-            catch ( IOException e )
-            {
+            } catch (IOException e) {
                 /*
                  * Problems reading from the actual ByteArrayInputStream should
                  * never happen so this will only ever be a ZipException.
                  */
                 LOGGER.atInfo().withThrowable(e).log("Possibly corrupt compression or non-compressed data");
             }
-        }
-        else
-        {
+        } else {
             // Raw data is not compressed.
             content = new ImageHeaderPNG(rawContent).extractPNG();
         }
@@ -186,8 +175,8 @@ public final class Picture {
         byte[] jpegContent = getContent();
 
         int pointer = 2;
-        int firstByte = jpegContent[pointer];
-        int secondByte = jpegContent[pointer + 1];
+        int firstByte;
+        int secondByte;
         int endOfPicture = jpegContent.length;
         while ( pointer < endOfPicture - 1 )
         {
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hdgf/dev/TestVSDDumper.java b/poi-scratchpad/src/test/java/org/apache/poi/hdgf/dev/TestVSDDumper.java
index 302eacc928..6a1a830a0b 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hdgf/dev/TestVSDDumper.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hdgf/dev/TestVSDDumper.java
@@ -26,7 +26,7 @@ import java.io.File;
 import java.io.PrintStream;
 
 import org.apache.poi.POIDataSamples;
-import org.apache.poi.util.NullPrintStream;
+import org.apache.commons.io.output.NullPrintStream;
 import org.junit.jupiter.api.Test;
 
 public class TestVSDDumper {
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hemf/usermodel/TestHemfPicture.java b/poi-scratchpad/src/test/java/org/apache/poi/hemf/usermodel/TestHemfPicture.java
index 6d39586729..d52873779c 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hemf/usermodel/TestHemfPicture.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hemf/usermodel/TestHemfPicture.java
@@ -26,7 +26,6 @@ import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.awt.geom.Point2D;
 import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.InputStream;
 import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
@@ -34,6 +33,7 @@ import java.util.HashSet;
 import java.util.List;
 import java.util.Set;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.POIDataSamples;
 import org.apache.poi.hemf.record.emf.HemfComment;
 import org.apache.poi.hemf.record.emf.HemfComment.EmfComment;
@@ -52,7 +52,6 @@ import org.apache.poi.util.IOUtils;
 import org.apache.poi.util.RecordFormatException;
 import org.junit.jupiter.api.Test;
 
-@SuppressWarnings("StatementWithEmptyBody")
 public class TestHemfPicture {
 
     private static final POIDataSamples ss_samples = POIDataSamples.getSpreadSheetInstance();
@@ -286,10 +285,10 @@ public class TestHemfPicture {
     @Test
     void testInfiniteLoopOnByteArray() throws Exception {
         try (InputStream is = ss_samples.openResourceAsStream("61294.emf")) {
-            ByteArrayOutputStream bos = new ByteArrayOutputStream();
+            UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream();
             IOUtils.copy(is, bos);
 
-            HemfPicture pic = new HemfPicture(new ByteArrayInputStream(bos.toByteArray()));
+            HemfPicture pic = new HemfPicture(bos.toInputStream());
             assertThrows(RecordFormatException.class, () -> pic.forEach(r -> {}));
         }
     }
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hmef/TestHMEFMessage.java b/poi-scratchpad/src/test/java/org/apache/poi/hmef/TestHMEFMessage.java
index d0359a6d2e..5717e5157d 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hmef/TestHMEFMessage.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hmef/TestHMEFMessage.java
@@ -21,15 +21,16 @@ import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertSame;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.nio.charset.StandardCharsets;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.POIDataSamples;
 import org.apache.poi.hmef.attribute.MAPIAttribute;
 import org.apache.poi.hmef.attribute.MAPIRtfAttribute;
@@ -83,10 +84,10 @@ public final class TestHMEFMessage {
         assertNotNull(msg.getMessageAttribute(TNEFProperty.ID_MAPIPROPERTIES));
 
         // Check the order
-        assertEquals(TNEFProperty.ID_TNEFVERSION, msg.getMessageAttributes().get(0).getProperty());
-        assertEquals(TNEFProperty.ID_OEMCODEPAGE, msg.getMessageAttributes().get(1).getProperty());
-        assertEquals(TNEFProperty.ID_MESSAGECLASS, msg.getMessageAttributes().get(2).getProperty());
-        assertEquals(TNEFProperty.ID_MAPIPROPERTIES, msg.getMessageAttributes().get(3).getProperty());
+        assertSame(TNEFProperty.ID_TNEFVERSION, msg.getMessageAttributes().get(0).getProperty());
+        assertSame(TNEFProperty.ID_OEMCODEPAGE, msg.getMessageAttributes().get(1).getProperty());
+        assertSame(TNEFProperty.ID_MESSAGECLASS, msg.getMessageAttributes().get(2).getProperty());
+        assertSame(TNEFProperty.ID_MAPIPROPERTIES, msg.getMessageAttributes().get(3).getProperty());
 
         // Check some that aren't there
         assertNull(msg.getMessageAttribute(TNEFProperty.ID_AIDOWNER));
@@ -168,7 +169,7 @@ public final class TestHMEFMessage {
 
     @Test
     void testNoData() throws Exception {
-        ByteArrayOutputStream out = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream out = new UnsynchronizedByteArrayOutputStream();
 
         // Header
         LittleEndian.putInt(HMEFMessage.HEADER_SIGNATURE, out);
@@ -176,16 +177,14 @@ public final class TestHMEFMessage {
         // field
         LittleEndian.putUShort(0, out);
 
-        byte[] bytes = out.toByteArray();
-        InputStream str = new ByteArrayInputStream(bytes);
-        HMEFMessage msg = new HMEFMessage(str);
+        HMEFMessage msg = new HMEFMessage(out.toInputStream());
         assertNull(msg.getSubject());
         assertNull(msg.getBody());
     }
 
     @Test
     void testInvalidLevel() throws Exception {
-        ByteArrayOutputStream out = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream out = new UnsynchronizedByteArrayOutputStream();
 
         // Header
         LittleEndian.putInt(HMEFMessage.HEADER_SIGNATURE, out);
@@ -196,10 +195,9 @@ public final class TestHMEFMessage {
         // invalid level
         LittleEndian.putUShort(90, out);
 
-        InputStream str = new ByteArrayInputStream(out.toByteArray());
         IllegalStateException ex = assertThrows(
             IllegalStateException.class,
-            () -> new HMEFMessage(str)
+            () -> new HMEFMessage(out.toInputStream())
         );
         assertEquals("Unhandled level 90", ex.getMessage());
     }
@@ -226,7 +224,7 @@ public final class TestHMEFMessage {
 
         MAPIStringAttribute propE28b = (MAPIStringAttribute)msg.getMessageMAPIAttribute(propE28);
         assertNotNull(propE28b);
-        assertEquals(MAPIStringAttribute.class, propE28b.getClass());
+        assertSame(MAPIStringAttribute.class, propE28b.getClass());
         assertEquals("Zimbra - Mark Rogers", propE28b.getDataString().substring(10));
     }
 
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hmef/dev/TestHMEFDumper.java b/poi-scratchpad/src/test/java/org/apache/poi/hmef/dev/TestHMEFDumper.java
index a24901a96d..49ef65cb83 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hmef/dev/TestHMEFDumper.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hmef/dev/TestHMEFDumper.java
@@ -28,7 +28,7 @@ import java.io.File;
 import java.io.PrintStream;
 
 import org.apache.poi.POIDataSamples;
-import org.apache.poi.util.NullPrintStream;
+import org.apache.commons.io.output.NullPrintStream;
 import org.junit.jupiter.api.Test;
 
 public class TestHMEFDumper {
@@ -38,13 +38,13 @@ public class TestHMEFDumper {
     }
 
     @Test
-    void main() throws Exception {
+    void main() {
         File file = POIDataSamples.getHMEFInstance().getFile("quick-winmail.dat");
         assertDoesNotThrow(() -> doMain(file.getAbsolutePath()));
     }
 
     @Test
-    void mainFull() throws Exception {
+    void mainFull() {
         File file = POIDataSamples.getHMEFInstance().getFile("quick-winmail.dat");
         assertDoesNotThrow(() -> doMain("--full", file.getAbsolutePath()));
     }
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hmef/extractor/TestHMEFContentsExtractor.java b/poi-scratchpad/src/test/java/org/apache/poi/hmef/extractor/TestHMEFContentsExtractor.java
index 4a786f5bca..81912bbba5 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hmef/extractor/TestHMEFContentsExtractor.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hmef/extractor/TestHMEFContentsExtractor.java
@@ -22,11 +22,11 @@ import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.IOException;
 import java.util.Arrays;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.POIDataSamples;
 import org.apache.poi.util.TempFile;
 import org.junit.jupiter.api.Test;
@@ -62,13 +62,13 @@ public class TestHMEFContentsExtractor {
         POIDataSamples samples = POIDataSamples.getHMEFInstance();
         File winmailTNEFFile = samples.getFile("quick-winmail.dat");
         HMEFContentsExtractor extractor = new HMEFContentsExtractor(winmailTNEFFile);
-        ByteArrayOutputStream out = new ByteArrayOutputStream();
-        extractor.extractMessageBody(out);
-        assertTrue(out.size() > 0);
-        byte[] expectedMagic = new byte[] { '{', '\\', 'r', 't', 'f' };
-        byte[] magic = Arrays.copyOf(out.toByteArray(), 5);
-        assertArrayEquals(expectedMagic, magic, "RTF magic number");
-        out.close();
+        try (UnsynchronizedByteArrayOutputStream out = new UnsynchronizedByteArrayOutputStream()) {
+            extractor.extractMessageBody(out);
+            assertTrue(out.size() > 0);
+            byte[] expectedMagic = new byte[]{'{', '\\', 'r', 't', 'f'};
+            byte[] magic = Arrays.copyOf(out.toByteArray(), 5);
+            assertArrayEquals(expectedMagic, magic, "RTF magic number");
+        }
     }
 
     @Test
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hslf/HSLFTestDataSamples.java b/poi-scratchpad/src/test/java/org/apache/poi/hslf/HSLFTestDataSamples.java
index 82b3a46091..9a08f18eb6 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hslf/HSLFTestDataSamples.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hslf/HSLFTestDataSamples.java
@@ -17,12 +17,11 @@
 
 package org.apache.poi.hslf;
 
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.POIDataSamples;
 import org.apache.poi.hslf.usermodel.HSLFSlideShow;
 import org.apache.poi.hslf.usermodel.HSLFSlideShowImpl;
@@ -50,32 +49,30 @@ public class HSLFTestDataSamples {
 	}
 
 	/**
-	 * Writes a slideshow to a {@code ByteArrayOutputStream} and reads it back
+	 * Writes a slideshow to a {@code UnsynchronizedByteArrayOutputStream} and reads it back
 	 * from a {@code ByteArrayInputStream}.<p>
 	 * Useful for verifying that the serialisation round trip
 	 */
 	public static HSLFSlideShowImpl writeOutAndReadBack(HSLFSlideShowImpl original) {
-		try {
-			ByteArrayOutputStream baos = new ByteArrayOutputStream(4096);
+		try (UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream()) {
 			original.write(baos);
-			ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
-			return new HSLFSlideShowImpl(bais);
+			try (InputStream is = baos.toInputStream()) {
+				return new HSLFSlideShowImpl(is);
+			}
 		} catch (IOException e) {
 			throw new RuntimeException(e);
 		}
 	}
 
 	/**
-	 * Writes a slideshow to a {@code ByteArrayOutputStream} and reads it back
+	 * Writes a slideshow to a {@code UnsynchronizedByteArrayOutputStream} and reads it back
 	 * from a {@code ByteArrayInputStream}.<p>
 	 * Useful for verifying that the serialisation round trip
 	 */
 	public static HSLFSlideShow writeOutAndReadBack(HSLFSlideShow original) {
-		try {
-			ByteArrayOutputStream baos = new ByteArrayOutputStream(4096);
+		try (UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream(4096)) {
 			original.write(baos);
-			ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
-			return new HSLFSlideShow(bais);
+			return new HSLFSlideShow(baos.toInputStream());
 		} catch (IOException e) {
 			throw new RuntimeException(e);
 		}
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hslf/TestPOIDocumentScratchpad.java b/poi-scratchpad/src/test/java/org/apache/poi/hslf/TestPOIDocumentScratchpad.java
index 774b1fb91b..2d795452b9 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hslf/TestPOIDocumentScratchpad.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hslf/TestPOIDocumentScratchpad.java
@@ -21,22 +21,18 @@
 package org.apache.poi.hslf;
 
 
+import static org.apache.poi.POIDataSamples.writeOutAndReadBack;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 
-import org.apache.poi.POIDataSamples;
 import org.apache.poi.POIDocument;
 import org.apache.poi.hpsf.DocumentSummaryInformation;
 import org.apache.poi.hpsf.HPSFPropertiesOnlyDocument;
 import org.apache.poi.hpsf.SummaryInformation;
-import org.apache.poi.hslf.usermodel.HSLFSlideShowImpl;
 import org.apache.poi.hwpf.HWPFTestDataSamples;
 import org.apache.poi.poifs.filesystem.POIFSFileSystem;
-import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
 /**
@@ -47,23 +43,11 @@ import org.junit.jupiter.api.Test;
  *  which are part of the scratchpad (not main)
  */
 public final class TestPOIDocumentScratchpad {
-	// The POI Documents to work on
-	private POIDocument doc;
-	private POIDocument doc2;
-
-	/**
-	 * Set things up, using a PowerPoint document and
-	 *  a Word Document for our testing
-	 */
-	@BeforeEach
-    void setUp() throws IOException {
-		doc = new HSLFSlideShowImpl(POIDataSamples.getSlideShowInstance().openResourceAsStream("basic_test_ppt_file.ppt"));
-		doc2 = HWPFTestDataSamples.openSampleFile("test2.doc");
-	}
-
 	@Test
-	void testReadProperties() {
-	    testReadPropertiesHelper(doc);
+	void testReadProperties() throws IOException {
+		try (POIDocument doc = HSLFTestDataSamples.getSlideShow("basic_test_ppt_file.ppt")) {
+			testReadPropertiesHelper(doc);
+		}
 	}
 
 	private void testReadPropertiesHelper(POIDocument docPH) {
@@ -77,49 +61,46 @@ public final class TestPOIDocumentScratchpad {
 	}
 
 	@Test
-	void testReadProperties2() {
-		// Check again on the word one
-		assertNotNull(doc2.getDocumentSummaryInformation());
-		assertNotNull(doc2.getSummaryInformation());
-
-		assertEquals("Hogwarts", doc2.getSummaryInformation().getAuthor());
-		assertEquals("", doc2.getSummaryInformation().getKeywords());
-		assertEquals(0, doc2.getDocumentSummaryInformation().getByteCount());
+	void testReadProperties2() throws IOException {
+		try (POIDocument doc2 = HWPFTestDataSamples.openSampleFile("test2.doc")) {
+			// Check again on the word one
+			assertNotNull(doc2.getDocumentSummaryInformation());
+			assertNotNull(doc2.getSummaryInformation());
+
+			assertEquals("Hogwarts", doc2.getSummaryInformation().getAuthor());
+			assertEquals("", doc2.getSummaryInformation().getKeywords());
+			assertEquals(0, doc2.getDocumentSummaryInformation().getByteCount());
+		}
 	}
 
 	@Test
 	void testWriteProperties() throws IOException {
 		// Just check we can write them back out into a filesystem
-		POIFSFileSystem outFS = new POIFSFileSystem();
-		doc.writeProperties(outFS);
-
-		// Should now hold them
-		assertNotNull(outFS.createDocumentInputStream(SummaryInformation.DEFAULT_STREAM_NAME));
-		assertNotNull(outFS.createDocumentInputStream(DocumentSummaryInformation.DEFAULT_STREAM_NAME));
-		outFS.close();
+		try (POIDocument doc = HSLFTestDataSamples.getSlideShow("basic_test_ppt_file.ppt");
+			 POIFSFileSystem outFS = new POIFSFileSystem()) {
+			doc.writeProperties(outFS);
+
+			// Should now hold them
+			assertNotNull(outFS.createDocumentInputStream(SummaryInformation.DEFAULT_STREAM_NAME));
+			assertNotNull(outFS.createDocumentInputStream(DocumentSummaryInformation.DEFAULT_STREAM_NAME));
+		}
 	}
 
 	@Test
     void testWriteReadProperties() throws IOException {
-		ByteArrayOutputStream baos = new ByteArrayOutputStream();
-
     	// Write them out
-    	POIFSFileSystem outFS = new POIFSFileSystem();
-    	doc.writeProperties(outFS);
-    	outFS.writeFilesystem(baos);
-
-    	// Create a new version
-    	ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
-    	POIFSFileSystem inFS = new POIFSFileSystem(bais);
-
-    	// Check they're still there
-    	POIDocument ppt = new HPSFPropertiesOnlyDocument(inFS);
-    	ppt.readProperties();
-
-    	// Delegate test
-    	testReadPropertiesHelper(ppt);
-
-    	ppt.close();
-    	inFS.close();
+		try (POIDocument doc = HSLFTestDataSamples.getSlideShow("basic_test_ppt_file.ppt");
+    		POIFSFileSystem outFS = new POIFSFileSystem()) {
+			doc.writeProperties(outFS);
+
+			// Check they're still there
+			try (POIFSFileSystem inFS = writeOutAndReadBack(outFS);
+				 POIDocument ppt = new HPSFPropertiesOnlyDocument(inFS)) {
+				ppt.readProperties();
+
+				// Delegate test
+				testReadPropertiesHelper(ppt);
+			}
+		}
     }
 }
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hslf/TestReWrite.java b/poi-scratchpad/src/test/java/org/apache/poi/hslf/TestReWrite.java
index 5aec58964a..687888a69a 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hslf/TestReWrite.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hslf/TestReWrite.java
@@ -25,12 +25,11 @@ import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.POIDataSamples;
 import org.apache.poi.hslf.usermodel.HSLFSlideShow;
 import org.apache.poi.hslf.usermodel.HSLFSlideShowImpl;
@@ -56,7 +55,7 @@ public final class TestReWrite {
              HSLFSlideShowImpl hss = new HSLFSlideShowImpl(pfs)) {
 
             // Write out to a byte array, and to a temp file
-            ByteArrayOutputStream baos = new ByteArrayOutputStream();
+            UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
             hss.write(baos);
 
             final File file = TempFile.createTempFile("TestHSLF", ".ppt");
@@ -66,8 +65,7 @@ public final class TestReWrite {
 
 
             // Build an input stream of it, and read back as a POIFS from the stream
-            ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
-            try (POIFSFileSystem npfS = new POIFSFileSystem(bais);
+            try (POIFSFileSystem npfS = new POIFSFileSystem(baos.toInputStream());
                 // And the same on the temp file
                 POIFSFileSystem npfF = new POIFSFileSystem(file)) {
 
@@ -97,18 +95,16 @@ public final class TestReWrite {
             assertNotNull(pfsC.getRoot().getEntry("Macros"));
 
             // Write out normally, will loose the macro stream
-            ByteArrayOutputStream baos = new ByteArrayOutputStream();
+            UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
             hssC.write(baos);
-            ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
-            try (POIFSFileSystem pfsNew = new POIFSFileSystem(bais)) {
+            try (POIFSFileSystem pfsNew = new POIFSFileSystem(baos.toInputStream())) {
                 assertFalse(pfsNew.getRoot().hasEntry("Macros"));
             }
 
             // But if we write out with nodes preserved, will be there
             baos.reset();
             hssC.write(baos, true);
-            bais = new ByteArrayInputStream(baos.toByteArray());
-            try (POIFSFileSystem pfsNew = new POIFSFileSystem(bais)) {
+            try (POIFSFileSystem pfsNew = new POIFSFileSystem(baos.toInputStream())) {
                 assertTrue(pfsNew.getRoot().hasEntry("Macros"));
             }
         }
@@ -138,14 +134,11 @@ public final class TestReWrite {
         assertDoesNotThrow(ss::getNotes);
 
         // Now write out to a byte array
-        ByteArrayOutputStream baos = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
         hss.write(baos);
 
-        // Build an input stream of it
-        ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
-
         // Use POIFS to query that lot
-        try (POIFSFileSystem npfs = new POIFSFileSystem(bais)) {
+        try (POIFSFileSystem npfs = new POIFSFileSystem(baos.toInputStream())) {
             assertSame(pfs, npfs);
         }
     }
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hslf/TestReWriteSanity.java b/poi-scratchpad/src/test/java/org/apache/poi/hslf/TestReWriteSanity.java
index 3aca727bee..b2991c1533 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hslf/TestReWriteSanity.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hslf/TestReWriteSanity.java
@@ -18,14 +18,15 @@
 package org.apache.poi.hslf;
 
 
+import static org.apache.commons.io.output.NullOutputStream.NULL_OUTPUT_STREAM;
 import static org.apache.poi.POITestCase.assertContains;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.util.HashMap;
 import java.util.Map;
 
+import org.apache.commons.io.output.CountingOutputStream;
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.POIDataSamples;
 import org.apache.poi.hslf.record.CurrentUserAtom;
 import org.apache.poi.hslf.record.PersistPtrHolder;
@@ -63,55 +64,50 @@ public final class TestReWriteSanity {
     @Test
     void testUserEditAtomsRight() throws Exception {
         // Write out to a byte array
-        ByteArrayOutputStream baos = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
         ss.write(baos);
 
-        // Build an input stream of it
-        ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
-
         // Create a new one from that
-        HSLFSlideShowImpl wss = new HSLFSlideShowImpl(bais);
-
-        // Find the location of the PersistPtrIncrementalBlocks and
-        // UserEditAtoms
-        Record[] r = wss.getRecords();
-        Map<Integer,Record> pp = new HashMap<>();
-        Map<Integer,Object> ue = new HashMap<>();
-        ue.put(Integer.valueOf(0),Integer.valueOf(0)); // Will show 0 if first
-        int pos = 0;
-        int lastUEPos = -1;
-
-        for (final Record rec : r) {
-            if(rec instanceof PersistPtrHolder) {
-                pp.put(Integer.valueOf(pos), rec);
-            }
-            if(rec instanceof UserEditAtom) {
-                ue.put(Integer.valueOf(pos), rec);
-                lastUEPos = pos;
+        try (HSLFSlideShowImpl wss = new HSLFSlideShowImpl(baos.toInputStream())) {
+
+            // Find the location of the PersistPtrIncrementalBlocks and
+            // UserEditAtoms
+            Record[] r = wss.getRecords();
+            Map<Integer, Record> pp = new HashMap<>();
+            Map<Integer, Object> ue = new HashMap<>();
+            ue.put(0, 0); // Will show 0 if first
+            int lastUEPos = -1;
+
+            CountingOutputStream cos = new CountingOutputStream(NULL_OUTPUT_STREAM);
+            for (final Record rec : r) {
+                int pos = cos.getCount();
+                if (rec instanceof PersistPtrHolder) {
+                    pp.put(pos, rec);
+                }
+                if (rec instanceof UserEditAtom) {
+                    ue.put(pos, rec);
+                    lastUEPos = pos;
+                }
+
+                rec.writeOut(cos);
             }
 
-            ByteArrayOutputStream bc = new ByteArrayOutputStream();
-            rec.writeOut(bc);
-            pos += bc.size();
-        }
-
-        // Check that the UserEditAtom's point to right stuff
-        for (final Record rec : r) {
-            if(rec instanceof UserEditAtom) {
-                UserEditAtom uea = (UserEditAtom)rec;
-                int luPos = uea.getLastUserEditAtomOffset();
-                int ppPos = uea.getPersistPointersOffset();
+            // Check that the UserEditAtom's point to right stuff
+            for (final Record rec : r) {
+                if (rec instanceof UserEditAtom) {
+                    UserEditAtom uea = (UserEditAtom) rec;
+                    int luPos = uea.getLastUserEditAtomOffset();
+                    int ppPos = uea.getPersistPointersOffset();
 
-                assertContains(ue, Integer.valueOf(luPos));
-                assertContains(pp, Integer.valueOf(ppPos));
+                    assertContains(ue, luPos);
+                    assertContains(pp, ppPos);
+                }
             }
-        }
-
-        // Check that the CurrentUserAtom points to the right UserEditAtom
-        CurrentUserAtom cua = wss.getCurrentUserAtom();
-        int listedUEPos = (int)cua.getCurrentEditOffset();
-        assertEquals(lastUEPos,listedUEPos);
 
-        wss.close();
+            // Check that the CurrentUserAtom points to the right UserEditAtom
+            CurrentUserAtom cua = wss.getCurrentUserAtom();
+            int listedUEPos = (int) cua.getCurrentEditOffset();
+            assertEquals(lastUEPos, listedUEPos);
+        }
     }
 }
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hslf/dev/BaseTestPPTIterating.java b/poi-scratchpad/src/test/java/org/apache/poi/hslf/dev/BaseTestPPTIterating.java
index 980d6538e8..ca5b1ac380 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hslf/dev/BaseTestPPTIterating.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hslf/dev/BaseTestPPTIterating.java
@@ -34,7 +34,7 @@ import org.apache.poi.POIDataSamples;
 import org.apache.poi.hslf.exceptions.EncryptedPowerPointFileException;
 import org.apache.poi.hslf.exceptions.OldPowerPointFormatException;
 import org.apache.poi.util.IOUtils;
-import org.apache.poi.util.NullPrintStream;
+import org.apache.commons.io.output.NullPrintStream;
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.parallel.Isolated;
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hslf/dev/TestSLWTListing.java b/poi-scratchpad/src/test/java/org/apache/poi/hslf/dev/TestSLWTListing.java
index 8ee2010fa7..3ac7adb84d 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hslf/dev/TestSLWTListing.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hslf/dev/TestSLWTListing.java
@@ -23,7 +23,7 @@ import java.io.IOException;
 import java.io.PrintStream;
 
 import org.apache.poi.EmptyFileException;
-import org.apache.poi.util.NullPrintStream;
+import org.apache.commons.io.output.NullPrintStream;
 import org.junit.jupiter.api.AfterAll;
 import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.Test;
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hslf/extractor/TestExtractor.java b/poi-scratchpad/src/test/java/org/apache/poi/hslf/extractor/TestExtractor.java
index bd8d634b12..5525cdf808 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hslf/extractor/TestExtractor.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hslf/extractor/TestExtractor.java
@@ -25,7 +25,6 @@ import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
@@ -35,7 +34,6 @@ import java.util.List;
 
 import com.zaxxer.sparsebits.SparseBitSet;
 import org.apache.commons.codec.binary.Base64;
-import org.apache.commons.codec.binary.Hex;
 import org.apache.poi.POIDataSamples;
 import org.apache.poi.hslf.usermodel.HSLFObjectShape;
 import org.apache.poi.hslf.usermodel.HSLFSlideShow;
@@ -50,7 +48,6 @@ import org.apache.poi.sl.usermodel.ObjectShape;
 import org.apache.poi.sl.usermodel.SlideShow;
 import org.apache.poi.sl.usermodel.SlideShowFactory;
 import org.apache.poi.util.IOUtils;
-import org.apache.poi.util.NullOutputStream;
 import org.junit.jupiter.api.Test;
 
 /**
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hslf/model/TestMovieShape.java b/poi-scratchpad/src/test/java/org/apache/poi/hslf/model/TestMovieShape.java
index a90c591190..336f6bc4f2 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hslf/model/TestMovieShape.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hslf/model/TestMovieShape.java
@@ -22,9 +22,8 @@ import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.awt.geom.Rectangle2D;
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.POIDataSamples;
 import org.apache.poi.hslf.usermodel.HSLFPictureData;
 import org.apache.poi.hslf.usermodel.HSLFSlide;
@@ -33,11 +32,11 @@ import org.apache.poi.sl.usermodel.PictureData.PictureType;
 import org.junit.jupiter.api.Test;
 
 /**
- * Test <code>MovieShape</code> object.
+ * Test {@code MovieShape} object.
  */
 public final class TestMovieShape {
 
-    private static POIDataSamples _slTests = POIDataSamples.getSlideShowInstance();
+    private static final POIDataSamples _slTests = POIDataSamples.getSlideShowInstance();
 
     @Test
     void testCreate() throws Exception {
@@ -58,10 +57,10 @@ public final class TestMovieShape {
         shape.setAutoPlay(false);
         assertFalse(shape.isAutoPlay());
 
-        ByteArrayOutputStream out = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream out = new UnsynchronizedByteArrayOutputStream();
         ppt.write(out);
 
-        ppt = new HSLFSlideShow(new ByteArrayInputStream(out.toByteArray()));
+        ppt = new HSLFSlideShow(out.toInputStream());
         slide = ppt.getSlides().get(0);
         shape = (MovieShape)slide.getShapes().get(0);
         assertEquals(path, shape.getPath());
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hslf/model/TestOleEmbedding.java b/poi-scratchpad/src/test/java/org/apache/poi/hslf/model/TestOleEmbedding.java
index 9c561fb18e..dbab7b9fdc 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hslf/model/TestOleEmbedding.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hslf/model/TestOleEmbedding.java
@@ -21,13 +21,12 @@ import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import java.awt.geom.Rectangle2D;
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
 import java.util.List;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.POIDataSamples;
 import org.apache.poi.hslf.usermodel.HSLFObjectData;
 import org.apache.poi.hslf.usermodel.HSLFObjectShape;
@@ -146,10 +145,10 @@ public final class TestOleEmbedding {
         slide2.addShape(oleShape2);
         oleShape2.setAnchor(new Rectangle2D.Double(100,100,100,100));
 
-    	ByteArrayOutputStream bos = new ByteArrayOutputStream();
+    	UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream();
     	ppt.write(bos);
 
-    	ppt = new HSLFSlideShow(new ByteArrayInputStream(bos.toByteArray()));
+    	ppt = new HSLFSlideShow(bos.toInputStream());
     	HSLFObjectShape comp = (HSLFObjectShape)ppt.getSlides().get(0).getShapes().get(0);
         byte[] compData = IOUtils.toByteArray(comp.getObjectData().getInputStream());
 
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hslf/model/TestSetBoldItalic.java b/poi-scratchpad/src/test/java/org/apache/poi/hslf/model/TestSetBoldItalic.java
index e47467c2ba..426eee09fb 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hslf/model/TestSetBoldItalic.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hslf/model/TestSetBoldItalic.java
@@ -17,12 +17,16 @@
 
 package org.apache.poi.hslf.model;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.apache.poi.hslf.HSLFTestDataSamples.writeOutAndReadBack;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
-
-import org.apache.poi.hslf.usermodel.*;
+import org.apache.poi.hslf.usermodel.HSLFSlide;
+import org.apache.poi.hslf.usermodel.HSLFSlideShow;
+import org.apache.poi.hslf.usermodel.HSLFTextBox;
+import org.apache.poi.hslf.usermodel.HSLFTextRun;
 import org.junit.jupiter.api.Test;
 
 /**
@@ -35,46 +39,46 @@ public final class TestSetBoldItalic {
      */
     @Test
     void testTextBoxWrite() throws Exception {
-        HSLFSlideShow ppt = new HSLFSlideShow();
-        HSLFSlide sl = ppt.createSlide();
-        HSLFTextRun rt;
-
-        String val = "Hello, World!";
+        try (HSLFSlideShow ppt = new HSLFSlideShow()) {
+            HSLFSlide sl = ppt.createSlide();
+            HSLFTextRun rt;
 
-        // Create a new textbox, and give it lots of properties
-        HSLFTextBox txtbox = new HSLFTextBox();
-        rt = txtbox.getTextParagraphs().get(0).getTextRuns().get(0);
-        txtbox.setText(val);
-        rt.setFontSize(42d);
-        rt.setBold(true);
-        rt.setItalic(true);
-        rt.setUnderlined(false);
-        sl.addShape(txtbox);
+            String val = "Hello, World!";
 
-        // Check it before save
-        rt = txtbox.getTextParagraphs().get(0).getTextRuns().get(0);
-        assertEquals(val, rt.getRawText());
-        assertEquals(42, rt.getFontSize(), 0);
-        assertTrue(rt.isBold());
-        assertTrue(rt.isItalic());
+            // Create a new textbox, and give it lots of properties
+            HSLFTextBox txtbox = new HSLFTextBox();
+            rt = txtbox.getTextParagraphs().get(0).getTextRuns().get(0);
+            txtbox.setText(val);
+            rt.setFontSize(42d);
+            rt.setBold(true);
+            rt.setItalic(true);
+            rt.setUnderlined(false);
+            sl.addShape(txtbox);
 
-        // Serialize and read again
-        ByteArrayOutputStream out = new ByteArrayOutputStream();
-        ppt.write(out);
-        out.close();
+            // Check it before save
+            rt = txtbox.getTextParagraphs().get(0).getTextRuns().get(0);
+            assertEquals(val, rt.getRawText());
+            assertNotNull(rt.getFontSize());
+            assertEquals(42, rt.getFontSize(), 0);
+            assertTrue(rt.isBold());
+            assertTrue(rt.isItalic());
 
-        ppt = new HSLFSlideShow(new HSLFSlideShowImpl(new ByteArrayInputStream(out.toByteArray())));
-        sl = ppt.getSlides().get(0);
+            // Serialize and read again
+            try (HSLFSlideShow ppt2 = writeOutAndReadBack(ppt)) {
+                sl = ppt2.getSlides().get(0);
 
-        txtbox = (HSLFTextBox)sl.getShapes().get(0);
-        rt = txtbox.getTextParagraphs().get(0).getTextRuns().get(0);
+                txtbox = (HSLFTextBox) sl.getShapes().get(0);
+                rt = txtbox.getTextParagraphs().get(0).getTextRuns().get(0);
 
-        // Check after save
-        assertEquals(val, rt.getRawText());
-        assertEquals(42, rt.getFontSize(), 0);
-        assertTrue(rt.isBold());
-        assertTrue(rt.isItalic());
-        assertFalse(rt.isUnderlined());
+                // Check after save
+                assertEquals(val, rt.getRawText());
+                assertNotNull(rt.getFontSize());
+                assertEquals(42, rt.getFontSize(), 0);
+                assertTrue(rt.isBold());
+                assertTrue(rt.isItalic());
+                assertFalse(rt.isUnderlined());
+            }
+        }
     }
 
 }
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hslf/model/TestShapes.java b/poi-scratchpad/src/test/java/org/apache/poi/hslf/model/TestShapes.java
index 774fe06468..84af931507 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hslf/model/TestShapes.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hslf/model/TestShapes.java
@@ -17,6 +17,9 @@
 
 package org.apache.poi.hslf.model;
 
+import static org.apache.poi.hslf.HSLFTestDataSamples.getSlideShow;
+import static org.apache.poi.hslf.HSLFTestDataSamples.openSampleFileStream;
+import static org.apache.poi.hslf.HSLFTestDataSamples.writeOutAndReadBack;
 import static org.apache.poi.sl.usermodel.BaseTestSlideShow.getColor;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
@@ -27,14 +30,10 @@ import static org.junit.jupiter.api.Assertions.assertTrue;
 import java.awt.Color;
 import java.awt.Dimension;
 import java.awt.geom.Rectangle2D;
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
-import java.io.InputStream;
 import java.util.ArrayList;
 import java.util.List;
 
-import org.apache.poi.POIDataSamples;
 import org.apache.poi.ddf.AbstractEscherOptRecord;
 import org.apache.poi.ddf.EscherDgRecord;
 import org.apache.poi.ddf.EscherDggRecord;
@@ -56,68 +55,52 @@ import org.apache.poi.hslf.usermodel.HSLFTextShape;
 import org.apache.poi.sl.usermodel.PictureData.PictureType;
 import org.apache.poi.sl.usermodel.ShapeType;
 import org.apache.poi.sl.usermodel.StrokeStyle.LineDash;
-import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
 
 /**
  * Test drawing shapes via Graphics2D
  */
 public final class TestShapes {
-    private static final POIDataSamples _slTests = POIDataSamples.getSlideShowInstance();
-
-    private HSLFSlideShow ppt;
-    private HSLFSlideShow pptB;
-
-    @BeforeEach
-    void setUp() throws Exception {
-        try (InputStream is1 = _slTests.openResourceAsStream("empty.ppt");
-             InputStream is2 = _slTests.openResourceAsStream("empty_textbox.ppt")) {
-            ppt = new HSLFSlideShow(is1);
-            pptB = new HSLFSlideShow(is2);
-        }
-    }
-
     @Test
     void graphics() throws IOException {
-        HSLFSlide slide = ppt.createSlide();
-
-        HSLFLine line = new HSLFLine();
-        java.awt.Rectangle lineAnchor = new java.awt.Rectangle(100, 200, 50, 60);
-        line.setAnchor(lineAnchor);
-        line.setLineWidth(3);
-        line.setLineDash(LineDash.DASH);
-        line.setLineColor(Color.red);
-        slide.addShape(line);
-
-        HSLFAutoShape ellipse = new HSLFAutoShape(ShapeType.ELLIPSE);
-        Rectangle2D ellipseAnchor = new Rectangle2D.Double(320, 154, 55, 111);
-        ellipse.setAnchor(ellipseAnchor);
-        ellipse.setLineWidth(2);
-        ellipse.setLineDash(LineDash.SOLID);
-        ellipse.setLineColor(Color.green);
-        ellipse.setFillColor(Color.lightGray);
-        slide.addShape(ellipse);
-
-        ByteArrayOutputStream out = new ByteArrayOutputStream();
-        ppt.write(out);
-        out.close();
-
-        //read ppt from byte array
-
-        HSLFSlideShow ppt2 = new HSLFSlideShow(new ByteArrayInputStream(out.toByteArray()));
-        assertEquals(1, ppt2.getSlides().size());
-
-        slide = ppt2.getSlides().get(0);
-        List<HSLFShape> shape = slide.getShapes();
-        assertEquals(2, shape.size());
-
-        assertTrue(shape.get(0) instanceof HSLFLine); //group shape
-        assertEquals(lineAnchor, shape.get(0).getAnchor()); //group shape
+        try (HSLFSlideShow ppt = getSlideShow("empty.ppt")) {
+            HSLFSlide slide = ppt.createSlide();
+
+            HSLFLine line = new HSLFLine();
+            java.awt.Rectangle lineAnchor = new java.awt.Rectangle(100, 200, 50, 60);
+            line.setAnchor(lineAnchor);
+            line.setLineWidth(3);
+            line.setLineDash(LineDash.DASH);
+            line.setLineColor(Color.red);
+            slide.addShape(line);
+
+            HSLFAutoShape ellipse = new HSLFAutoShape(ShapeType.ELLIPSE);
+            Rectangle2D ellipseAnchor = new Rectangle2D.Double(320, 154, 55, 111);
+            ellipse.setAnchor(ellipseAnchor);
+            ellipse.setLineWidth(2);
+            ellipse.setLineDash(LineDash.SOLID);
+            ellipse.setLineColor(Color.green);
+            ellipse.setFillColor(Color.lightGray);
+            slide.addShape(ellipse);
+
+            //read ppt from byte array
+            try (HSLFSlideShow ppt2 = writeOutAndReadBack(ppt)) {
+                assertEquals(1, ppt2.getSlides().size());
+
+                slide = ppt2.getSlides().get(0);
+                List<HSLFShape> shape = slide.getShapes();
+                assertEquals(2, shape.size());
+
+                assertTrue(shape.get(0) instanceof HSLFLine); //group shape
+                assertEquals(lineAnchor, shape.get(0).getAnchor()); //group shape
+
+                assertTrue(shape.get(1) instanceof HSLFAutoShape); //group shape
+                assertEquals(ellipseAnchor, shape.get(1).getAnchor()); //group shape
 
-        assertTrue(shape.get(1) instanceof HSLFAutoShape); //group shape
-        assertEquals(ellipseAnchor, shape.get(1).getAnchor()); //group shape
-
-        ppt2.close();
+            }
+        }
     }
 
     /**
@@ -125,40 +108,41 @@ public final class TestShapes {
      */
     @Test
     void textBoxRead() throws IOException {
-        ppt = new HSLFSlideShow(_slTests.openResourceAsStream("with_textbox.ppt"));
-        HSLFSlide sl = ppt.getSlides().get(0);
-        for (HSLFShape sh : sl.getShapes()) {
-            assertTrue(sh instanceof HSLFTextBox);
-            HSLFTextBox txtbox = (HSLFTextBox)sh;
-            String text = txtbox.getText();
-            assertNotNull(text);
-
-            assertEquals(txtbox.getTextParagraphs().get(0).getTextRuns().size(), 1);
-            HSLFTextRun rt = txtbox.getTextParagraphs().get(0).getTextRuns().get(0);
-
-            switch (text) {
-                case "Hello, World!!!":
-                    assertNotNull(rt.getFontSize());
-                    assertEquals(32, rt.getFontSize(), 0);
-                    assertTrue(rt.isBold());
-                    assertTrue(rt.isItalic());
-                    break;
-                case "I am just a poor boy":
-                    assertNotNull(rt.getFontSize());
-                    assertEquals(44, rt.getFontSize(), 0);
-                    assertTrue(rt.isBold());
-                    break;
-                case "This is Times New Roman":
-                    assertNotNull(rt.getFontSize());
-                    assertEquals(16, rt.getFontSize(), 0);
-                    assertTrue(rt.isBold());
-                    assertTrue(rt.isItalic());
-                    assertTrue(rt.isUnderlined());
-                    break;
-                case "Plain Text":
-                    assertNotNull(rt.getFontSize());
-                    assertEquals(18, rt.getFontSize(), 0);
-                    break;
+        try (HSLFSlideShow ppt = getSlideShow("with_textbox.ppt")) {
+            HSLFSlide sl = ppt.getSlides().get(0);
+            for (HSLFShape sh : sl.getShapes()) {
+                assertTrue(sh instanceof HSLFTextBox);
+                HSLFTextBox txtbox = (HSLFTextBox) sh;
+                String text = txtbox.getText();
+                assertNotNull(text);
+
+                assertEquals(txtbox.getTextParagraphs().get(0).getTextRuns().size(), 1);
+                HSLFTextRun rt = txtbox.getTextParagraphs().get(0).getTextRuns().get(0);
+
+                switch (text) {
+                    case "Hello, World!!!":
+                        assertNotNull(rt.getFontSize());
+                        assertEquals(32, rt.getFontSize(), 0);
+                        assertTrue(rt.isBold());
+                        assertTrue(rt.isItalic());
+                        break;
+                    case "I am just a poor boy":
+                        assertNotNull(rt.getFontSize());
+                        assertEquals(44, rt.getFontSize(), 0);
+                        assertTrue(rt.isBold());
+                        break;
+                    case "This is Times New Roman":
+                        assertNotNull(rt.getFontSize());
+                        assertEquals(16, rt.getFontSize(), 0);
+                        assertTrue(rt.isBold());
+                        assertTrue(rt.isItalic());
+                        assertTrue(rt.isUnderlined());
+                        break;
+                    case "Plain Text":
+                        assertNotNull(rt.getFontSize());
+                        assertEquals(18, rt.getFontSize(), 0);
+                        break;
+                }
             }
         }
     }
@@ -166,43 +150,42 @@ public final class TestShapes {
     @SuppressWarnings("unused")
     @Test
     void testParagraphs() throws IOException {
-        HSLFSlideShow ss = new HSLFSlideShow();
-        HSLFSlide slide = ss.createSlide();
-        HSLFTextBox shape = new HSLFTextBox();
-        HSLFTextRun p1r1 = shape.setText("para 1 run 1. ");
-        HSLFTextRun p1r2 = shape.appendText("para 1 run 2.", false);
-        HSLFTextRun p2r1 = shape.appendText("para 2 run 1. ", true);
-        HSLFTextRun p2r2 = shape.appendText("para 2 run 2. ", false);
-        p1r1.setFontColor(Color.black);
-        p1r2.setFontColor(Color.red);
-        p2r1.setFontColor(Color.yellow);
-        p2r2.setStrikethrough(true);
-        // run 3 has same text properties as run 2 and will be merged when saving
-        HSLFTextRun p2r3 = shape.appendText("para 2 run 3.", false);
-        shape.setAnchor(new Rectangle2D.Double(100,100,100,10));
-        slide.addShape(shape);
-        shape.resizeToFitText();
-
-        ByteArrayOutputStream bos = new ByteArrayOutputStream();
-        ss.write(bos);
-
-        ss = new HSLFSlideShow(new ByteArrayInputStream(bos.toByteArray()));
-        slide = ss.getSlides().get(0);
-        HSLFTextBox tb = (HSLFTextBox)slide.getShapes().get(0);
-        List<HSLFTextParagraph> para = tb.getTextParagraphs();
-        HSLFTextRun tr = para.get(0).getTextRuns().get(0);
-        assertEquals("para 1 run 1. ", tr.getRawText());
-        assertEquals(Color.black, getColor(tr.getFontColor()));
-        tr = para.get(0).getTextRuns().get(1);
-        assertEquals("para 1 run 2.\r",  tr.getRawText());
-        assertEquals(Color.red, getColor(tr.getFontColor()));
-        tr = para.get(1).getTextRuns().get(0);
-        assertEquals("para 2 run 1. ", tr.getRawText());
-        assertEquals(Color.yellow, getColor(tr.getFontColor()));
-        tr = para.get(1).getTextRuns().get(1);
-        assertEquals("para 2 run 2. para 2 run 3.", tr.getRawText());
-        assertEquals(Color.black, getColor(tr.getFontColor()));
-        assertTrue(tr.isStrikethrough());
+        try (HSLFSlideShow ppt1 = new HSLFSlideShow()) {
+            HSLFSlide slide = ppt1.createSlide();
+            HSLFTextBox shape = new HSLFTextBox();
+            HSLFTextRun p1r1 = shape.setText("para 1 run 1. ");
+            HSLFTextRun p1r2 = shape.appendText("para 1 run 2.", false);
+            HSLFTextRun p2r1 = shape.appendText("para 2 run 1. ", true);
+            HSLFTextRun p2r2 = shape.appendText("para 2 run 2. ", false);
+            p1r1.setFontColor(Color.black);
+            p1r2.setFontColor(Color.red);
+            p2r1.setFontColor(Color.yellow);
+            p2r2.setStrikethrough(true);
+            // run 3 has same text properties as run 2 and will be merged when saving
+            HSLFTextRun p2r3 = shape.appendText("para 2 run 3.", false);
+            shape.setAnchor(new Rectangle2D.Double(100, 100, 100, 10));
+            slide.addShape(shape);
+            shape.resizeToFitText();
+
+            try (HSLFSlideShow ppt2 = writeOutAndReadBack(ppt1)) {
+                slide = ppt2.getSlides().get(0);
+                HSLFTextBox tb = (HSLFTextBox) slide.getShapes().get(0);
+                List<HSLFTextParagraph> para = tb.getTextParagraphs();
+                HSLFTextRun tr = para.get(0).getTextRuns().get(0);
+                assertEquals("para 1 run 1. ", tr.getRawText());
+                assertEquals(Color.black, getColor(tr.getFontColor()));
+                tr = para.get(0).getTextRuns().get(1);
+                assertEquals("para 1 run 2.\r", tr.getRawText());
+                assertEquals(Color.red, getColor(tr.getFontColor()));
+                tr = para.get(1).getTextRuns().get(0);
+                assertEquals("para 2 run 1. ", tr.getRawText());
+                assertEquals(Color.yellow, getColor(tr.getFontColor()));
+                tr = para.get(1).getTextRuns().get(1);
+                assertEquals("para 2 run 2. para 2 run 3.", tr.getRawText());
+                assertEquals(Color.black, getColor(tr.getFontColor()));
+                assertTrue(tr.isStrikethrough());
+            }
+        }
     }
 
 
@@ -212,169 +195,158 @@ public final class TestShapes {
      */
     @Test
     void textBoxWriteBytes() throws IOException {
-        ppt = new HSLFSlideShow();
-        HSLFSlide sl = ppt.createSlide();
-        HSLFTextRun rt;
-
-        String val = "Hello, World!";
-
-        // Create a new textbox, and give it lots of properties
-        HSLFTextBox txtbox = new HSLFTextBox();
-        rt = txtbox.getTextParagraphs().get(0).getTextRuns().get(0);
-        txtbox.setText(val);
-        rt.setFontFamily("Arial");
-        rt.setFontSize(42d);
-        rt.setBold(true);
-        rt.setItalic(true);
-        rt.setUnderlined(false);
-        rt.setFontColor(Color.red);
-        sl.addShape(txtbox);
-
-        // Check it before save
-        rt = txtbox.getTextParagraphs().get(0).getTextRuns().get(0);
-        assertEquals(val, rt.getRawText());
-        assertNotNull(rt.getFontSize());
-        assertEquals(42, rt.getFontSize(), 0);
-        assertTrue(rt.isBold());
-        assertTrue(rt.isItalic());
-        assertFalse(rt.isUnderlined());
-        assertEquals("Arial", rt.getFontFamily());
-        assertEquals(Color.red, getColor(rt.getFontColor()));
-
-        // Serialize and read again
-        ByteArrayOutputStream out = new ByteArrayOutputStream();
-        ppt.write(out);
-        out.close();
-
-        HSLFSlideShow ppt2 = new HSLFSlideShow(new ByteArrayInputStream(out.toByteArray()));
-        sl = ppt2.getSlides().get(0);
-
-        txtbox = (HSLFTextBox)sl.getShapes().get(0);
-        rt = txtbox.getTextParagraphs().get(0).getTextRuns().get(0);
-
-        // Check after save
-        assertEquals(val, rt.getRawText());
-        assertNotNull(rt.getFontSize());
-        assertEquals(42, rt.getFontSize(), 0);
-        assertTrue(rt.isBold());
-        assertTrue(rt.isItalic());
-        assertFalse(rt.isUnderlined());
-        assertEquals("Arial", rt.getFontFamily());
-        assertEquals(Color.red, getColor(rt.getFontColor()));
-
-        ppt2.close();
+        try (HSLFSlideShow ppt1 = new HSLFSlideShow()) {
+            HSLFSlide sl = ppt1.createSlide();
+
+            String val = "Hello, World!";
+
+            // Create a new textbox, and give it lots of properties
+            HSLFTextBox txtbox = new HSLFTextBox();
+            HSLFTextRun rt = txtbox.getTextParagraphs().get(0).getTextRuns().get(0);
+            txtbox.setText(val);
+            rt.setFontFamily("Arial");
+            rt.setFontSize(42d);
+            rt.setBold(true);
+            rt.setItalic(true);
+            rt.setUnderlined(false);
+            rt.setFontColor(Color.red);
+            sl.addShape(txtbox);
+
+            // Check it before save
+            rt = txtbox.getTextParagraphs().get(0).getTextRuns().get(0);
+            assertEquals(val, rt.getRawText());
+            assertNotNull(rt.getFontSize());
+            assertEquals(42, rt.getFontSize(), 0);
+            assertTrue(rt.isBold());
+            assertTrue(rt.isItalic());
+            assertFalse(rt.isUnderlined());
+            assertEquals("Arial", rt.getFontFamily());
+            assertEquals(Color.red, getColor(rt.getFontColor()));
+
+            // Serialize and read again
+            try (HSLFSlideShow ppt2 = writeOutAndReadBack(ppt1)) {
+                sl = ppt2.getSlides().get(0);
+
+                txtbox = (HSLFTextBox) sl.getShapes().get(0);
+                rt = txtbox.getTextParagraphs().get(0).getTextRuns().get(0);
+
+                // Check after save
+                assertEquals(val, rt.getRawText());
+                assertNotNull(rt.getFontSize());
+                assertEquals(42, rt.getFontSize(), 0);
+                assertTrue(rt.isBold());
+                assertTrue(rt.isItalic());
+                assertFalse(rt.isUnderlined());
+                assertEquals("Arial", rt.getFontFamily());
+                assertEquals(Color.red, getColor(rt.getFontColor()));
+            }
+        }
     }
 
     /**
      * Test with an empty text box
      */
     @Test
-    void emptyTextBox() {
-    	assertEquals(2, pptB.getSlides().size());
-    	HSLFSlide s1 = pptB.getSlides().get(0);
-    	HSLFSlide s2 = pptB.getSlides().get(1);
-
-    	// Check we can get the shapes count
-    	assertEquals(2, s1.getShapes().size());
-    	assertEquals(2, s2.getShapes().size());
+    void emptyTextBox() throws IOException {
+        try (HSLFSlideShow ppt = getSlideShow("empty_textbox.ppt")) {
+            assertEquals(2, ppt.getSlides().size());
+            HSLFSlide s1 = ppt.getSlides().get(0);
+            HSLFSlide s2 = ppt.getSlides().get(1);
+
+            // Check we can get the shapes count
+            assertEquals(2, s1.getShapes().size());
+            assertEquals(2, s2.getShapes().size());
+        }
     }
 
     /**
      * If you iterate over text shapes in a slide and collect them in a set
      * it must be the same as returned by Slide.getTextRuns().
      */
-    @Test
-    void textBoxSet() throws IOException {
-        textBoxSet("with_textbox.ppt");
-        textBoxSet("basic_test_ppt_file.ppt");
-        textBoxSet("next_test_ppt_file.ppt");
-        textBoxSet("Single_Coloured_Page.ppt");
-        textBoxSet("Single_Coloured_Page_With_Fonts_and_Alignments.ppt");
-        textBoxSet("incorrect_slide_order.ppt");
-    }
-
-    private void textBoxSet(String filename) throws IOException {
-        HSLFSlideShow ss = new HSLFSlideShow(_slTests.openResourceAsStream(filename));
-        for (HSLFSlide sld : ss.getSlides()) {
-            ArrayList<String> lst1 = new ArrayList<>();
-            for (List<HSLFTextParagraph> txt : sld.getTextParagraphs()) {
-                for (HSLFTextParagraph p : txt) {
-                    for (HSLFTextRun r : p) {
-                        lst1.add(r.getRawText());
+    @ParameterizedTest
+    @ValueSource(strings = {
+        "with_textbox.ppt",
+        "basic_test_ppt_file.ppt",
+        "next_test_ppt_file.ppt",
+        "Single_Coloured_Page.ppt",
+        "Single_Coloured_Page_With_Fonts_and_Alignments.ppt",
+        "incorrect_slide_order.ppt"
+    })
+    void textBoxSet(String filename) throws IOException {
+        try (HSLFSlideShow ppt = getSlideShow(filename)) {
+            for (HSLFSlide sld : ppt.getSlides()) {
+                ArrayList<String> lst1 = new ArrayList<>();
+                for (List<HSLFTextParagraph> txt : sld.getTextParagraphs()) {
+                    for (HSLFTextParagraph p : txt) {
+                        for (HSLFTextRun r : p) {
+                            lst1.add(r.getRawText());
+                        }
                     }
                 }
-            }
 
-            ArrayList<String> lst2 = new ArrayList<>();
-            for (HSLFShape sh : sld.getShapes()) {
-                if (sh instanceof HSLFTextShape){
-                    HSLFTextShape tbox = (HSLFTextShape)sh;
-                    for (HSLFTextParagraph p : tbox.getTextParagraphs()) {
-                        for (HSLFTextRun r : p) {
-                            lst2.add(r.getRawText());
+                ArrayList<String> lst2 = new ArrayList<>();
+                for (HSLFShape sh : sld.getShapes()) {
+                    if (sh instanceof HSLFTextShape) {
+                        HSLFTextShape tbox = (HSLFTextShape) sh;
+                        for (HSLFTextParagraph p : tbox.getTextParagraphs()) {
+                            for (HSLFTextRun r : p) {
+                                lst2.add(r.getRawText());
+                            }
                         }
                     }
                 }
+                assertTrue(lst1.containsAll(lst2));
+                assertTrue(lst2.containsAll(lst1));
             }
-            assertTrue(lst1.containsAll(lst2));
-            assertTrue(lst2.containsAll(lst1));
         }
-        ss.close();
     }
 
     /**
-     * Test adding shapes to <code>ShapeGroup</code>
+     * Test adding shapes to {@code ShapeGroup}
      */
     @Test
     void shapeGroup() throws IOException {
-        HSLFSlideShow ss = new HSLFSlideShow();
-
-        HSLFSlide slide = ss.createSlide();
-        Dimension pgsize = ss.getPageSize();
-
-        HSLFGroupShape group = new HSLFGroupShape();
+        try (HSLFSlideShow ppt1 = new HSLFSlideShow()) {
 
-        group.setAnchor(new Rectangle2D.Double(0, 0, pgsize.getWidth(), pgsize.getHeight()));
-        slide.addShape(group);
+            HSLFSlide slide = ppt1.createSlide();
+            Dimension pgsize = ppt1.getPageSize();
 
-        HSLFPictureData data = ss.addPicture(_slTests.readFile("clock.jpg"), PictureType.JPEG);
-        HSLFPictureShape pict = new HSLFPictureShape(data, group);
-        pict.setAnchor(new Rectangle2D.Double(0, 0, 200, 200));
-        group.addShape(pict);
+            HSLFGroupShape group = new HSLFGroupShape();
 
-        HSLFLine line = new HSLFLine(group);
-        line.setAnchor(new Rectangle2D.Double(300, 300, 500, 0));
-        group.addShape(line);
+            group.setAnchor(new Rectangle2D.Double(0, 0, pgsize.getWidth(), pgsize.getHeight()));
+            slide.addShape(group);
 
-        //serialize and read again.
-        ByteArrayOutputStream  out = new ByteArrayOutputStream();
-        ss.write(out);
-        out.close();
-        ss.close();
+            HSLFPictureData data = ppt1.addPicture(openSampleFileStream("clock.jpg"), PictureType.JPEG);
+            HSLFPictureShape pict = new HSLFPictureShape(data, group);
+            pict.setAnchor(new Rectangle2D.Double(0, 0, 200, 200));
+            group.addShape(pict);
 
-        ByteArrayInputStream is = new ByteArrayInputStream(out.toByteArray());
-        ss = new HSLFSlideShow(is);
-        is.close();
+            HSLFLine line = new HSLFLine(group);
+            line.setAnchor(new Rectangle2D.Double(300, 300, 500, 0));
+            group.addShape(line);
 
-        slide = ss.getSlides().get(0);
+            //serialize and read again.
+            try (HSLFSlideShow ppt2 = writeOutAndReadBack(ppt1)) {
 
-        List<HSLFShape> shape = slide.getShapes();
-        assertEquals(1, shape.size());
-        assertTrue(shape.get(0) instanceof HSLFGroupShape);
+                slide = ppt2.getSlides().get(0);
 
-        group = (HSLFGroupShape)shape.get(0);
-        List<HSLFShape> grshape = group.getShapes();
-        assertEquals(2, grshape.size());
-        assertTrue(grshape.get(0) instanceof HSLFPictureShape);
-        assertTrue(grshape.get(1) instanceof HSLFLine);
+                List<HSLFShape> shape = slide.getShapes();
+                assertEquals(1, shape.size());
+                assertTrue(shape.get(0) instanceof HSLFGroupShape);
 
-        pict = (HSLFPictureShape)grshape.get(0);
-        assertEquals(new Rectangle2D.Double(0, 0, 200, 200), pict.getAnchor());
+                group = (HSLFGroupShape) shape.get(0);
+                List<HSLFShape> grshape = group.getShapes();
+                assertEquals(2, grshape.size());
+                assertTrue(grshape.get(0) instanceof HSLFPictureShape);
+                assertTrue(grshape.get(1) instanceof HSLFLine);
 
-        line = (HSLFLine)grshape.get(1);
-        assertEquals(new Rectangle2D.Double(300, 300, 500, 0), line.getAnchor());
+                pict = (HSLFPictureShape) grshape.get(0);
+                assertEquals(new Rectangle2D.Double(0, 0, 200, 200), pict.getAnchor());
 
-        ss.close();
+                line = (HSLFLine) grshape.get(1);
+                assertEquals(new Rectangle2D.Double(300, 300, 500, 0), line.getAnchor());
+            }
+        }
     }
 
     /**
@@ -382,29 +354,24 @@ public final class TestShapes {
      */
     @Test
     void removeShapes() throws IOException {
-        String file = "with_textbox.ppt";
-        HSLFSlideShow ss = new HSLFSlideShow(_slTests.openResourceAsStream(file));
-        HSLFSlide sl = ss.getSlides().get(0);
-        List<HSLFShape> sh = sl.getShapes();
-        assertEquals(4, sh.size(), "expected four shaped in " + file);
-        //remove all
-        for (int i = 0; i < sh.size(); i++) {
-            boolean ok = sl.removeShape(sh.get(i));
-            assertTrue(ok, "Failed to delete shape #" + i);
+        try (HSLFSlideShow ppt1 = getSlideShow("with_textbox.ppt")) {
+            HSLFSlide sl = ppt1.getSlides().get(0);
+            List<HSLFShape> sh = sl.getShapes();
+            assertEquals(4, sh.size());
+            //remove all
+            for (int i = 0; i < sh.size(); i++) {
+                boolean ok = sl.removeShape(sh.get(i));
+                assertTrue(ok, "Failed to delete shape #" + i);
+            }
+            //now Slide.getShapes() should return an empty array
+            assertEquals(0, sl.getShapes().size());
+
+            //serialize and read again. The file should be readable and contain no shapes
+            try (HSLFSlideShow ppt2 = writeOutAndReadBack(ppt1)) {
+                sl = ppt2.getSlides().get(0);
+                assertEquals(0, sl.getShapes().size());
+            }
         }
-        //now Slide.getShapes() should return an empty array
-        assertEquals(0, sl.getShapes().size(), "expected 0 shaped in " + file);
-
-        //serialize and read again. The file should be readable and contain no shapes
-        ByteArrayOutputStream out = new ByteArrayOutputStream();
-        ss.write(out);
-        out.close();
-        ss.close();
-
-        ss = new HSLFSlideShow(new ByteArrayInputStream(out.toByteArray()));
-        sl = ss.getSlides().get(0);
-        assertEquals(0, sl.getShapes().size(), "expected 0 shaped in " + file);
-        ss.close();
     }
 
     @Test
@@ -424,79 +391,78 @@ public final class TestShapes {
 
     @Test
     void shapeId() throws IOException {
-        HSLFSlideShow ss = new HSLFSlideShow();
-        HSLFSlide slide = ss.createSlide();
-
-        //EscherDgg is a document-level record which keeps track of the drawing groups
-        EscherDggRecord dgg = ss.getDocumentRecord().getPPDrawingGroup().getEscherDggRecord();
-        EscherDgRecord dg = slide.getSheetContainer().getPPDrawing().getEscherDgRecord();
-
-        int dggShapesUsed = dgg.getNumShapesSaved();   //total number of shapes in the ppt
-        int dggMaxId = dgg.getShapeIdMax();            //max number of shapeId
-
-        int dgMaxId = dg.getLastMSOSPID();   //max shapeId in the slide
-        int dgShapesUsed = dg.getNumShapes();          // number of shapes in the slide
-        //insert 3 shapes and make sure the Ids are properly incremented
-        for (int i = 0; i < 3; i++) {
-            HSLFShape shape = new HSLFLine();
-            assertEquals(0, shape.getShapeId());
-            slide.addShape(shape);
-            assertTrue(shape.getShapeId() > 0);
-
-            //check that EscherDgRecord is updated
-            assertEquals(shape.getShapeId(), dg.getLastMSOSPID());
-            assertEquals(dgMaxId + 1, dg.getLastMSOSPID());
-            assertEquals(dgShapesUsed + 1, dg.getNumShapes());
-
-            //check that EscherDggRecord is updated
-            assertEquals(shape.getShapeId() + 1, dgg.getShapeIdMax(), "mismatch @"+i);
-            assertEquals(dggMaxId + 1, dgg.getShapeIdMax(), "mismatch @"+i);
-            assertEquals(dggShapesUsed + 1, dgg.getNumShapesSaved(), "mismatch @"+i);
-
-            dggShapesUsed = dgg.getNumShapesSaved();
-            dggMaxId = dgg.getShapeIdMax();
-            dgMaxId = dg.getLastMSOSPID();
-            dgShapesUsed = dg.getNumShapes();
-        }
+        try (HSLFSlideShow ppt = new HSLFSlideShow()) {
+            HSLFSlide slide = ppt.createSlide();
+
+            //EscherDgg is a document-level record which keeps track of the drawing groups
+            EscherDggRecord dgg = ppt.getDocumentRecord().getPPDrawingGroup().getEscherDggRecord();
+            EscherDgRecord dg = slide.getSheetContainer().getPPDrawing().getEscherDgRecord();
+
+            int dggShapesUsed = dgg.getNumShapesSaved();   //total number of shapes in the ppt
+            int dggMaxId = dgg.getShapeIdMax();            //max number of shapeId
+
+            int dgMaxId = dg.getLastMSOSPID();   //max shapeId in the slide
+            int dgShapesUsed = dg.getNumShapes();          // number of shapes in the slide
+            //insert 3 shapes and make sure the Ids are properly incremented
+            for (int i = 0; i < 3; i++) {
+                HSLFShape shape = new HSLFLine();
+                assertEquals(0, shape.getShapeId());
+                slide.addShape(shape);
+                assertTrue(shape.getShapeId() > 0);
+
+                //check that EscherDgRecord is updated
+                assertEquals(shape.getShapeId(), dg.getLastMSOSPID());
+                assertEquals(dgMaxId + 1, dg.getLastMSOSPID());
+                assertEquals(dgShapesUsed + 1, dg.getNumShapes());
+
+                //check that EscherDggRecord is updated
+                assertEquals(shape.getShapeId() + 1, dgg.getShapeIdMax(), "mismatch @" + i);
+                assertEquals(dggMaxId + 1, dgg.getShapeIdMax(), "mismatch @" + i);
+                assertEquals(dggShapesUsed + 1, dgg.getNumShapesSaved(), "mismatch @" + i);
+
+                dggShapesUsed = dgg.getNumShapesSaved();
+                dggMaxId = dgg.getShapeIdMax();
+                dgMaxId = dg.getLastMSOSPID();
+                dgShapesUsed = dg.getNumShapes();
+            }
 
 
-        //For each drawing group PPT allocates clusters with size=1024
-        //if the number of shapes is greater that 1024 a new cluster is allocated
-        //make sure it is so
-        int numClusters = dgg.getNumIdClusters();
-        for (int i = 0; i < 1025; i++) {
-            HSLFShape shape = new HSLFLine();
-            slide.addShape(shape);
+            //For each drawing group PPT allocates clusters with size=1024
+            //if the number of shapes is greater that 1024 a new cluster is allocated
+            //make sure it is so
+            int numClusters = dgg.getNumIdClusters();
+            for (int i = 0; i < 1025; i++) {
+                HSLFShape shape = new HSLFLine();
+                slide.addShape(shape);
+            }
+            assertEquals(numClusters + 1, dgg.getNumIdClusters());
         }
-        assertEquals(numClusters + 1, dgg.getNumIdClusters());
-        ss.close();
     }
 
     @Test
     void lineColor() throws IOException {
-        HSLFSlideShow ss = new HSLFSlideShow(_slTests.openResourceAsStream("51731.ppt"));
-        List<HSLFShape> shape = ss.getSlides().get(0).getShapes();
-
-        assertEquals(4, shape.size());
+        try (HSLFSlideShow ss = getSlideShow("51731.ppt")) {
+            List<HSLFShape> shape = ss.getSlides().get(0).getShapes();
 
-        HSLFTextShape sh1 = (HSLFTextShape)shape.get(0);
-        assertEquals("Hello Apache POI", sh1.getText());
-        assertNull(sh1.getLineColor());
+            assertEquals(4, shape.size());
 
-        HSLFTextShape sh2 = (HSLFTextShape)shape.get(1);
-        assertEquals("Why are you showing this border?", sh2.getText());
-        assertNull(sh2.getLineColor());
+            HSLFTextShape sh1 = (HSLFTextShape) shape.get(0);
+            assertEquals("Hello Apache POI", sh1.getText());
+            assertNull(sh1.getLineColor());
 
-        HSLFTextShape sh3 = (HSLFTextShape)shape.get(2);
-        assertEquals("Text in a black border", sh3.getText());
-        assertEquals(Color.black, sh3.getLineColor());
-        assertEquals(0.75, sh3.getLineWidth(), 0);
+            HSLFTextShape sh2 = (HSLFTextShape) shape.get(1);
+            assertEquals("Why are you showing this border?", sh2.getText());
+            assertNull(sh2.getLineColor());
 
-        HSLFTextShape sh4 = (HSLFTextShape)shape.get(3);
-        assertEquals("Border width is 5 pt", sh4.getText());
-        assertEquals(Color.black, sh4.getLineColor());
-        assertEquals(5.0, sh4.getLineWidth(), 0);
+            HSLFTextShape sh3 = (HSLFTextShape) shape.get(2);
+            assertEquals("Text in a black border", sh3.getText());
+            assertEquals(Color.black, sh3.getLineColor());
+            assertEquals(0.75, sh3.getLineWidth(), 0);
 
-        ss.close();
+            HSLFTextShape sh4 = (HSLFTextShape) shape.get(3);
+            assertEquals("Border width is 5 pt", sh4.getText());
+            assertEquals(Color.black, sh4.getLineColor());
+            assertEquals(5.0, sh4.getLineWidth(), 0);
+        }
     }
 }
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hslf/model/TestSlideMaster.java b/poi-scratchpad/src/test/java/org/apache/poi/hslf/model/TestSlideMaster.java
index a50958ff79..8c00994768 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hslf/model/TestSlideMaster.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hslf/model/TestSlideMaster.java
@@ -17,28 +17,32 @@
 
 package org.apache.poi.hslf.model;
 
+import static org.apache.poi.hslf.HSLFTestDataSamples.getSlideShow;
+import static org.apache.poi.hslf.HSLFTestDataSamples.writeOutAndReadBack;
 import static org.apache.poi.sl.usermodel.TextShape.TextPlaceholder.BODY;
 import static org.apache.poi.sl.usermodel.TextShape.TextPlaceholder.CENTER_BODY;
 import static org.apache.poi.sl.usermodel.TextShape.TextPlaceholder.CENTER_TITLE;
 import static org.apache.poi.sl.usermodel.TextShape.TextPlaceholder.TITLE;
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.util.List;
+import java.util.Objects;
+import java.util.stream.IntStream;
 
 import org.apache.poi.POIDataSamples;
 import org.apache.poi.hslf.model.textproperties.CharFlagsTextProp;
 import org.apache.poi.hslf.model.textproperties.TextProp;
 import org.apache.poi.hslf.record.Environment;
+import org.apache.poi.hslf.usermodel.HSLFFontInfo;
 import org.apache.poi.hslf.usermodel.HSLFMasterSheet;
 import org.apache.poi.hslf.usermodel.HSLFSlide;
 import org.apache.poi.hslf.usermodel.HSLFSlideMaster;
 import org.apache.poi.hslf.usermodel.HSLFSlideShow;
-import org.apache.poi.hslf.usermodel.HSLFSlideShowImpl;
 import org.apache.poi.hslf.usermodel.HSLFTextParagraph;
 import org.apache.poi.hslf.usermodel.HSLFTextRun;
 import org.apache.poi.hslf.usermodel.HSLFTitleMaster;
@@ -49,7 +53,7 @@ import org.junit.jupiter.api.Test;
  * Tests for SlideMaster
  */
 public final class TestSlideMaster {
-    private static POIDataSamples _slTests = POIDataSamples.getSlideShowInstance();
+    private static final POIDataSamples _slTests = POIDataSamples.getSlideShowInstance();
 
     /**
      * The reference ppt has two masters.
@@ -57,46 +61,54 @@ public final class TestSlideMaster {
      */
     @Test
     void testSlideMaster() throws IOException {
-        final HSLFSlideShow ppt = new HSLFSlideShow(_slTests.openResourceAsStream("slide_master.ppt"));
-
-        final Environment env = ppt.getDocumentRecord().getEnvironment();
-
-        assertEquals(2, ppt.getSlideMasters().size());
-
-        //character attributes
-        assertEquals(40, getMasterVal(ppt, 0, TITLE, "font.size", true));
-        assertEquals(48, getMasterVal(ppt, 1, TITLE, "font.size", true));
-
-        int font1 = getMasterVal(ppt, 0, TITLE, "font.index", true);
-        int font2 = getMasterVal(ppt, 1, TITLE, "font.index", true);
-        assertEquals("Arial", env.getFontCollection().getFontInfo(font1).getTypeface());
-        assertEquals("Georgia", env.getFontCollection().getFontInfo(font2).getTypeface());
-
-        CharFlagsTextProp prop1 = getMasterProp(ppt, 0, TITLE, "char_flags", true);
-        assertFalse(prop1.getSubValue(CharFlagsTextProp.BOLD_IDX));
-        assertFalse(prop1.getSubValue(CharFlagsTextProp.ITALIC_IDX));
-        assertTrue(prop1.getSubValue(CharFlagsTextProp.UNDERLINE_IDX));
-
-        CharFlagsTextProp prop2 = getMasterProp(ppt, 1, TITLE, "char_flags", true);
-        assertFalse(prop2.getSubValue(CharFlagsTextProp.BOLD_IDX));
-        assertTrue(prop2.getSubValue(CharFlagsTextProp.ITALIC_IDX));
-        assertFalse(prop2.getSubValue(CharFlagsTextProp.UNDERLINE_IDX));
-
-        //now paragraph attributes
-        assertEquals(0x266B, getMasterVal(ppt, 0, BODY, "bullet.char", false));
-        assertEquals(0x2022, getMasterVal(ppt, 1, BODY, "bullet.char", false));
-
-        int b1 = getMasterVal(ppt, 0, BODY, "bullet.font", false);
-        int b2 = getMasterVal(ppt, 1, BODY, "bullet.font", false);
-        assertEquals("Arial", env.getFontCollection().getFontInfo(b1).getTypeface());
-        assertEquals("Georgia", env.getFontCollection().getFontInfo(b2).getTypeface());
-
-        ppt.close();
+        try (HSLFSlideShow ppt = getSlideShow("slide_master.ppt")) {
+
+            final Environment env = ppt.getDocumentRecord().getEnvironment();
+
+            assertEquals(2, ppt.getSlideMasters().size());
+
+            //character attributes
+            assertEquals(40, getMasterVal(ppt, 0, TITLE, "font.size", true));
+            assertEquals(48, getMasterVal(ppt, 1, TITLE, "font.size", true));
+
+            int font1 = getMasterVal(ppt, 0, TITLE, "font.index", true);
+            int font2 = getMasterVal(ppt, 1, TITLE, "font.index", true);
+            HSLFFontInfo fontInfo = env.getFontCollection().getFontInfo(font1);
+            assertNotNull(fontInfo);
+            assertEquals("Arial", fontInfo.getTypeface());
+            fontInfo = env.getFontCollection().getFontInfo(font2);
+            assertNotNull(fontInfo);
+            assertEquals("Georgia", fontInfo.getTypeface());
+
+            CharFlagsTextProp prop1 = getMasterProp(ppt, 0, TITLE, "char_flags", true);
+            assertFalse(prop1.getSubValue(CharFlagsTextProp.BOLD_IDX));
+            assertFalse(prop1.getSubValue(CharFlagsTextProp.ITALIC_IDX));
+            assertTrue(prop1.getSubValue(CharFlagsTextProp.UNDERLINE_IDX));
+
+            CharFlagsTextProp prop2 = getMasterProp(ppt, 1, TITLE, "char_flags", true);
+            assertFalse(prop2.getSubValue(CharFlagsTextProp.BOLD_IDX));
+            assertTrue(prop2.getSubValue(CharFlagsTextProp.ITALIC_IDX));
+            assertFalse(prop2.getSubValue(CharFlagsTextProp.UNDERLINE_IDX));
+
+            //now paragraph attributes
+            assertEquals(0x266B, getMasterVal(ppt, 0, BODY, "bullet.char", false));
+            assertEquals(0x2022, getMasterVal(ppt, 1, BODY, "bullet.char", false));
+
+            int b1 = getMasterVal(ppt, 0, BODY, "bullet.font", false);
+            int b2 = getMasterVal(ppt, 1, BODY, "bullet.font", false);
+            fontInfo = env.getFontCollection().getFontInfo(b1);
+            assertNotNull(fontInfo);
+            assertEquals("Arial", fontInfo.getTypeface());
+            fontInfo = env.getFontCollection().getFontInfo(b2);
+            assertNotNull(fontInfo);
+            assertEquals("Georgia", fontInfo.getTypeface());
+        }
     }
 
-    @SuppressWarnings("unchecked")
     private static <T extends TextProp> T getMasterProp(HSLFSlideShow ppt, int masterIdx, TextPlaceholder txtype, String propName, boolean isCharacter) {
-        return (T)ppt.getSlideMasters().get(masterIdx).getPropCollection(txtype.nativeId, 0, propName, isCharacter).findByName(propName);
+        return Objects.requireNonNull(ppt.getSlideMasters().get(masterIdx)
+            .getPropCollection(txtype.nativeId, 0, propName, isCharacter))
+            .findByName(propName);
     }
 
     private static int getMasterVal(HSLFSlideShow ppt, int masterIdx, TextPlaceholder txtype, String propName, boolean isCharacter) {
@@ -109,22 +121,21 @@ public final class TestSlideMaster {
      */
     @Test
     void testTitleMasterTextAttributes() throws IOException {
-        HSLFSlideShow ppt = new HSLFSlideShow(_slTests.openResourceAsStream("slide_master.ppt"));
-        assertEquals(1, ppt.getTitleMasters().size());
-
-        assertEquals(40, getMasterVal(ppt, 0, CENTER_TITLE, "font.size", true));
-        CharFlagsTextProp prop1 = getMasterProp(ppt, 0, CENTER_TITLE, "char_flags", true);
-        assertFalse(prop1.getSubValue(CharFlagsTextProp.BOLD_IDX));
-        assertFalse(prop1.getSubValue(CharFlagsTextProp.ITALIC_IDX));
-        assertTrue(prop1.getSubValue(CharFlagsTextProp.UNDERLINE_IDX));
-
-        assertEquals(32, getMasterVal(ppt, 0, CENTER_BODY, "font.size", true));
-        CharFlagsTextProp prop2 = getMasterProp(ppt, 0, CENTER_BODY, "char_flags", true);
-        assertFalse(prop2.getSubValue(CharFlagsTextProp.BOLD_IDX));
-        assertFalse(prop2.getSubValue(CharFlagsTextProp.ITALIC_IDX));
-        assertFalse(prop2.getSubValue(CharFlagsTextProp.UNDERLINE_IDX));
-
-        ppt.close();
+        try (HSLFSlideShow ppt = getSlideShow("slide_master.ppt")) {
+            assertEquals(1, ppt.getTitleMasters().size());
+
+            assertEquals(40, getMasterVal(ppt, 0, CENTER_TITLE, "font.size", true));
+            CharFlagsTextProp prop1 = getMasterProp(ppt, 0, CENTER_TITLE, "char_flags", true);
+            assertFalse(prop1.getSubValue(CharFlagsTextProp.BOLD_IDX));
+            assertFalse(prop1.getSubValue(CharFlagsTextProp.ITALIC_IDX));
+            assertTrue(prop1.getSubValue(CharFlagsTextProp.UNDERLINE_IDX));
+
+            assertEquals(32, getMasterVal(ppt, 0, CENTER_BODY, "font.size", true));
+            CharFlagsTextProp prop2 = getMasterProp(ppt, 0, CENTER_BODY, "char_flags", true);
+            assertFalse(prop2.getSubValue(CharFlagsTextProp.BOLD_IDX));
+            assertFalse(prop2.getSubValue(CharFlagsTextProp.ITALIC_IDX));
+            assertFalse(prop2.getSubValue(CharFlagsTextProp.UNDERLINE_IDX));
+        }
     }
 
     /**
@@ -132,30 +143,32 @@ public final class TestSlideMaster {
      */
     @Test
     void testTitleMaster() throws IOException {
-        HSLFSlideShow ppt = new HSLFSlideShow(_slTests.openResourceAsStream("slide_master.ppt"));
-        HSLFSlide slide = ppt.getSlides().get(2);
-        HSLFMasterSheet masterSheet = slide.getMasterSheet();
-        assertTrue(masterSheet instanceof HSLFTitleMaster);
-
-        for (List<HSLFTextParagraph> txt : slide.getTextParagraphs()) {
-            HSLFTextRun rt = txt.get(0).getTextRuns().get(0);
-            switch(TextPlaceholder.fromNativeId(txt.get(0).getRunType())){
-                case CENTER_TITLE:
-                    assertEquals("Arial", rt.getFontFamily());
-                    assertEquals(32, rt.getFontSize(), 0);
-                    assertTrue(rt.isBold());
-                    assertTrue(rt.isUnderlined());
-                    break;
-                case CENTER_BODY:
-                    assertEquals("Courier New", rt.getFontFamily());
-                    assertEquals(20, rt.getFontSize(), 0);
-                    assertTrue(rt.isBold());
-                    assertFalse(rt.isUnderlined());
-                    break;
+        try (HSLFSlideShow ppt = getSlideShow("slide_master.ppt")) {
+            HSLFSlide slide = ppt.getSlides().get(2);
+            HSLFMasterSheet masterSheet = slide.getMasterSheet();
+            assertTrue(masterSheet instanceof HSLFTitleMaster);
+
+            for (List<HSLFTextParagraph> txt : slide.getTextParagraphs()) {
+                HSLFTextRun rt = txt.get(0).getTextRuns().get(0);
+                assertNotNull(rt.getFontSize());
+                TextPlaceholder tp = TextPlaceholder.fromNativeId(txt.get(0).getRunType());
+                assertNotNull(tp);
+                switch (tp) {
+                    case CENTER_TITLE:
+                        assertEquals("Arial", rt.getFontFamily());
+                        assertEquals(32, rt.getFontSize(), 0);
+                        assertTrue(rt.isBold());
+                        assertTrue(rt.isUnderlined());
+                        break;
+                    case CENTER_BODY:
+                        assertEquals("Courier New", rt.getFontFamily());
+                        assertEquals(20, rt.getFontSize(), 0);
+                        assertTrue(rt.isBold());
+                        assertFalse(rt.isUnderlined());
+                        break;
+                }
             }
-
         }
-        ppt.close();
     }
 
     /**
@@ -163,48 +176,46 @@ public final class TestSlideMaster {
      */
     @Test
     void testMasterAttributes() throws Exception {
-        HSLFSlideShow ppt = new HSLFSlideShow(_slTests.openResourceAsStream("slide_master.ppt"));
-        List<HSLFSlide> slide = ppt.getSlides();
-        assertEquals(3, slide.size());
-        for (List<HSLFTextParagraph> tparas : slide.get(0).getTextParagraphs()) {
-            HSLFTextParagraph tpara = tparas.get(0);
-            if (tpara.getRunType() == TITLE.nativeId){
-                HSLFTextRun rt = tpara.getTextRuns().get(0);
-                assertEquals(40, rt.getFontSize(), 0);
-                assertTrue(rt.isUnderlined());
-                assertEquals("Arial", rt.getFontFamily());
-            } else if (tpara.getRunType() == BODY.nativeId){
+        try (HSLFSlideShow ppt = getSlideShow("slide_master.ppt")) {
+            List<HSLFSlide> slide = ppt.getSlides();
+            assertEquals(3, slide.size());
+            for (List<HSLFTextParagraph> tparas : slide.get(0).getTextParagraphs()) {
+                HSLFTextParagraph tpara = tparas.get(0);
                 HSLFTextRun rt = tpara.getTextRuns().get(0);
-                assertEquals(0, tpara.getIndentLevel());
-                assertEquals(32, rt.getFontSize(), 0);
-                assertEquals("Arial", rt.getFontFamily());
-
-                tpara = tparas.get(1);
-                rt = tpara.getTextRuns().get(0);
-                assertEquals(1, tpara.getIndentLevel());
-                assertEquals(28, rt.getFontSize(), 0);
-                assertEquals("Arial", rt.getFontFamily());
+                assertNotNull(rt.getFontSize());
+                if (tpara.getRunType() == TITLE.nativeId) {
+                    assertEquals(40, rt.getFontSize(), 0);
+                    assertTrue(rt.isUnderlined());
+                    assertEquals("Arial", rt.getFontFamily());
+                } else if (tpara.getRunType() == BODY.nativeId) {
+                    assertEquals(0, tpara.getIndentLevel());
+                    assertEquals(32, rt.getFontSize(), 0);
+                    assertEquals("Arial", rt.getFontFamily());
 
+                    tpara = tparas.get(1);
+                    rt = tpara.getTextRuns().get(0);
+                    assertEquals(1, tpara.getIndentLevel());
+                    assertNotNull(rt.getFontSize());
+                    assertEquals(28, rt.getFontSize(), 0);
+                    assertEquals("Arial", rt.getFontFamily());
+                }
             }
-        }
 
-        for (List<HSLFTextParagraph> tparas : slide.get(1).getTextParagraphs()) {
-            HSLFTextParagraph tpara = tparas.get(0);
-            if (tpara.getRunType() == TITLE.nativeId){
+            for (List<HSLFTextParagraph> tparas : slide.get(1).getTextParagraphs()) {
+                HSLFTextParagraph tpara = tparas.get(0);
                 HSLFTextRun rt = tpara.getTextRuns().get(0);
-                assertEquals(48, rt.getFontSize(), 0);
-                assertTrue(rt.isItalic());
-                assertEquals("Georgia", rt.getFontFamily());
-            } else if (tpara.getRunType() == BODY.nativeId){
-                HSLFTextRun rt;
-                rt = tpara.getTextRuns().get(0);
-                assertEquals(0, tpara.getIndentLevel());
-                assertEquals(32, rt.getFontSize(), 0);
-                assertEquals("Courier New", rt.getFontFamily());
+                assertNotNull(rt.getFontSize());
+                if (tpara.getRunType() == TITLE.nativeId) {
+                    assertEquals(48, rt.getFontSize(), 0);
+                    assertTrue(rt.isItalic());
+                    assertEquals("Georgia", rt.getFontFamily());
+                } else if (tpara.getRunType() == BODY.nativeId) {
+                    assertEquals(0, tpara.getIndentLevel());
+                    assertEquals(32, rt.getFontSize(), 0);
+                    assertEquals("Courier New", rt.getFontFamily());
+                }
             }
         }
-
-        ppt.close();
     }
 
     /**
@@ -212,35 +223,32 @@ public final class TestSlideMaster {
      */
     @Test
     void testChangeSlideMaster() throws IOException {
-        HSLFSlideShow ppt = new HSLFSlideShow(_slTests.openResourceAsStream("slide_master.ppt"));
-        List<HSLFSlideMaster> master = ppt.getSlideMasters();
-        List<HSLFSlide> slide = ppt.getSlides();
-        int sheetNo;
-
-        //each slide uses its own master
-        assertEquals(slide.get(0).getMasterSheet()._getSheetNumber(), master.get(0)._getSheetNumber());
-        assertEquals(slide.get(1).getMasterSheet()._getSheetNumber(), master.get(1)._getSheetNumber());
-
-        //all slides use the first master slide
-        sheetNo = master.get(0)._getSheetNumber();
-        for (HSLFSlide s : slide) {
-            s.setMasterSheet(master.get(0));
-        }
-
-        ByteArrayOutputStream out;
-
-        out = new ByteArrayOutputStream();
-        ppt.write(out);
-        out.close();
-
-        ppt = new HSLFSlideShow(new HSLFSlideShowImpl(new ByteArrayInputStream(out.toByteArray())));
-        master = ppt.getSlideMasters();
-        slide = ppt.getSlides();
-        for (HSLFSlide s : slide) {
-            assertEquals(sheetNo, s.getMasterSheet()._getSheetNumber());
+        try (HSLFSlideShow ppt = new HSLFSlideShow(_slTests.openResourceAsStream("slide_master.ppt"))) {
+            int[] masterIds = IntStream.concat(
+                ppt.getSlideMasters().stream().mapToInt(HSLFSlideMaster::_getSheetNumber),
+                ppt.getTitleMasters().stream().mapToInt(HSLFTitleMaster::_getSheetNumber)
+            ).toArray();
+            //each slide uses its own master
+            int[] slideMasters = ppt.getSlides().stream().mapToInt(s -> {
+                HSLFMasterSheet m = s.getMasterSheet();
+                assertNotNull(m);
+                return m._getSheetNumber();
+            }).toArray();
+            assertArrayEquals(masterIds, slideMasters);
+
+            //all slides use the first master slide
+            HSLFSlideMaster master0 = ppt.getSlideMasters().get(0);
+            int sheetNo = master0._getSheetNumber();
+            ppt.getSlides().forEach(s -> s.setMasterSheet(master0));
+
+            try (HSLFSlideShow ppt2 = writeOutAndReadBack(ppt)) {
+                for (HSLFSlide s : ppt2.getSlides()) {
+                    HSLFMasterSheet ms = s.getMasterSheet();
+                    assertNotNull(ms);
+                    assertEquals(sheetNo, ms._getSheetNumber());
+                }
+            }
         }
-
-        ppt.close();
     }
 
     /**
@@ -256,6 +264,7 @@ public final class TestSlideMaster {
             HSLFTextParagraph tpara = tparas.get(0);
             if (tpara.getRunType() == TITLE.nativeId){
                 HSLFTextRun rt = tpara.getTextRuns().get(0);
+                assertNotNull(rt.getFontSize());
                 assertEquals(40, rt.getFontSize(), 0);
                 assertTrue(rt.isUnderlined());
                 assertEquals("Arial", rt.getFontFamily());
@@ -263,6 +272,7 @@ public final class TestSlideMaster {
                 int[] indents = {32, 28, 24};
                 for (HSLFTextRun rt : tpara.getTextRuns()) {
                     int indent = tpara.getIndentLevel();
+                    assertNotNull(rt.getFontSize());
                     assertEquals(indents[indent], rt.getFontSize(), 0);
                 }
             }
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hslf/model/TestSlides.java b/poi-scratchpad/src/test/java/org/apache/poi/hslf/model/TestSlides.java
index 31713bae88..15850e6047 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hslf/model/TestSlides.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hslf/model/TestSlides.java
@@ -17,14 +17,13 @@
 
 package org.apache.poi.hslf.model;
 
+import static org.apache.poi.hslf.HSLFTestDataSamples.getSlideShow;
+import static org.apache.poi.hslf.HSLFTestDataSamples.writeOutAndReadBack;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
-
-import org.apache.poi.POIDataSamples;
-import org.apache.poi.hslf.usermodel.*;
+import org.apache.poi.hslf.usermodel.HSLFSlide;
+import org.apache.poi.hslf.usermodel.HSLFSlideShow;
 import org.junit.jupiter.api.Test;
 
 /**
@@ -36,105 +35,96 @@ public final class TestSlides {
 
     /**
      * Add 1 slide to an empty ppt.
-     * @throws Exception
      */
     @Test
     void testAddSlides1() throws Exception {
-        HSLFSlideShow ppt = new HSLFSlideShow(new HSLFSlideShowImpl( TestSlides.class.getResourceAsStream("/org/apache/poi/hslf/data/empty.ppt") ));
-        assertTrue(ppt.getSlides().isEmpty());
-
-        HSLFSlide s1 = ppt.createSlide();
-        assertEquals(1, ppt.getSlides().size());
-        assertEquals(3, s1._getSheetRefId());
-        assertEquals(256, s1._getSheetNumber());
-        assertEquals(1, s1.getSlideNumber());
-
-        //serialize and read again
-        ByteArrayOutputStream out = new ByteArrayOutputStream();
-        ppt.write(out);
-        out.close();
-
-        ppt = new HSLFSlideShow(new HSLFSlideShowImpl(new ByteArrayInputStream(out.toByteArray())));
-        assertEquals(1, ppt.getSlides().size());
+        try (HSLFSlideShow ppt1 = new HSLFSlideShow()) {
+            assertTrue(ppt1.getSlides().isEmpty());
+
+            HSLFSlide s1 = ppt1.createSlide();
+            assertEquals(1, ppt1.getSlides().size());
+            assertEquals(3, s1._getSheetRefId());
+            assertEquals(256, s1._getSheetNumber());
+            assertEquals(1, s1.getSlideNumber());
+
+            //serialize and read again
+            try (HSLFSlideShow ppt2 = writeOutAndReadBack(ppt1)){
+                assertEquals(1, ppt2.getSlides().size());
+            }
+        }
     }
 
     /**
      * Add 2 slides to an empty ppt
-     * @throws Exception
      */
     @Test
     void testAddSlides2() throws Exception {
-        HSLFSlideShow ppt = new HSLFSlideShow(new HSLFSlideShowImpl( TestSlides.class.getResourceAsStream("/org/apache/poi/hslf/data/empty.ppt") ));
-        assertTrue(ppt.getSlides().isEmpty());
-
-        HSLFSlide s1 = ppt.createSlide();
-        assertEquals(1, ppt.getSlides().size());
-        assertEquals(3, s1._getSheetRefId());
-        assertEquals(256, s1._getSheetNumber());
-        assertEquals(1, s1.getSlideNumber());
-
-        HSLFSlide s2 = ppt.createSlide();
-        assertEquals(2, ppt.getSlides().size());
-        assertEquals(4, s2._getSheetRefId());
-        assertEquals(257, s2._getSheetNumber());
-        assertEquals(2, s2.getSlideNumber());
-
-        //serialize and read again
-        ByteArrayOutputStream out = new ByteArrayOutputStream();
-        ppt.write(out);
-        out.close();
-
-        ppt = new HSLFSlideShow(new HSLFSlideShowImpl(new ByteArrayInputStream(out.toByteArray())));
-        assertEquals(2, ppt.getSlides().size());
+        try (HSLFSlideShow ppt1 = new HSLFSlideShow()) {
+            assertTrue(ppt1.getSlides().isEmpty());
+
+            HSLFSlide s1 = ppt1.createSlide();
+            assertEquals(1, ppt1.getSlides().size());
+            assertEquals(3, s1._getSheetRefId());
+            assertEquals(256, s1._getSheetNumber());
+            assertEquals(1, s1.getSlideNumber());
+
+            HSLFSlide s2 = ppt1.createSlide();
+            assertEquals(2, ppt1.getSlides().size());
+            assertEquals(4, s2._getSheetRefId());
+            assertEquals(257, s2._getSheetNumber());
+            assertEquals(2, s2.getSlideNumber());
+
+            //serialize and read again
+            try (HSLFSlideShow ppt2 = writeOutAndReadBack(ppt1)) {
+                assertEquals(2, ppt2.getSlides().size());
+            }
+        }
     }
 
     /**
      * Add 3 slides to an empty ppt
-     * @throws Exception
      */
     @Test
     void testAddSlides3() throws Exception {
-        HSLFSlideShow ppt = new HSLFSlideShow(new HSLFSlideShowImpl( TestSlides.class.getResourceAsStream("/org/apache/poi/hslf/data/empty.ppt") ));
-        assertTrue(ppt.getSlides().isEmpty());
-
-        HSLFSlide s1 = ppt.createSlide();
-        assertEquals(1, ppt.getSlides().size());
-        assertEquals(3, s1._getSheetRefId());
-        assertEquals(256, s1._getSheetNumber());
-        assertEquals(1, s1.getSlideNumber());
-
-        HSLFSlide s2 = ppt.createSlide();
-        assertEquals(2, ppt.getSlides().size());
-        assertEquals(4, s2._getSheetRefId());
-        assertEquals(257, s2._getSheetNumber());
-        assertEquals(2, s2.getSlideNumber());
-
-        HSLFSlide s3 = ppt.createSlide();
-        assertEquals(3, ppt.getSlides().size());
-        assertEquals(5, s3._getSheetRefId());
-        assertEquals(258, s3._getSheetNumber());
-        assertEquals(3, s3.getSlideNumber());
-
-
-        //serialize and read again
-         ByteArrayOutputStream out = new ByteArrayOutputStream();
-        ppt.write(out);
-        out.close();
-
-        ppt = new HSLFSlideShow(new HSLFSlideShowImpl(new ByteArrayInputStream(out.toByteArray())));
-        assertEquals(3, ppt.getSlides().size());
-
-        // Check IDs are still right
-        s1 = ppt.getSlides().get(0);
-        assertEquals(256, s1._getSheetNumber());
-        assertEquals(3, s1._getSheetRefId());
-        s2 = ppt.getSlides().get(1);
-        assertEquals(257, s2._getSheetNumber());
-        assertEquals(4, s2._getSheetRefId());
-        s3 = ppt.getSlides().get(2);
-        assertEquals(3, ppt.getSlides().size());
-        assertEquals(258, s3._getSheetNumber());
-        assertEquals(5, s3._getSheetRefId());
+        try (HSLFSlideShow ppt1 = new HSLFSlideShow()) {
+            assertTrue(ppt1.getSlides().isEmpty());
+
+            HSLFSlide s1 = ppt1.createSlide();
+            assertEquals(1, ppt1.getSlides().size());
+            assertEquals(3, s1._getSheetRefId());
+            assertEquals(256, s1._getSheetNumber());
+            assertEquals(1, s1.getSlideNumber());
+
+            HSLFSlide s2 = ppt1.createSlide();
+            assertEquals(2, ppt1.getSlides().size());
+            assertEquals(4, s2._getSheetRefId());
+            assertEquals(257, s2._getSheetNumber());
+            assertEquals(2, s2.getSlideNumber());
+
+            HSLFSlide s3 = ppt1.createSlide();
+            assertEquals(3, ppt1.getSlides().size());
+            assertEquals(5, s3._getSheetRefId());
+            assertEquals(258, s3._getSheetNumber());
+            assertEquals(3, s3.getSlideNumber());
+
+
+            //serialize and read again
+            try (HSLFSlideShow ppt2 = writeOutAndReadBack(ppt1)) {
+                assertEquals(3, ppt2.getSlides().size());
+
+                // Check IDs are still right
+                s1 = ppt2.getSlides().get(0);
+                assertEquals(256, s1._getSheetNumber());
+                assertEquals(3, s1._getSheetRefId());
+                s2 = ppt2.getSlides().get(1);
+                assertEquals(257, s2._getSheetNumber());
+                assertEquals(4, s2._getSheetRefId());
+                s3 = ppt2.getSlides().get(2);
+                assertEquals(3, ppt2.getSlides().size());
+                assertEquals(258, s3._getSheetNumber());
+                assertEquals(5, s3._getSheetRefId());
+            }
+        }
     }
 
     /**
@@ -142,48 +132,42 @@ public final class TestSlides {
      */
     @Test
     void testAddSlides2to3() throws Exception {
-        POIDataSamples slTests = POIDataSamples.getSlideShowInstance();
-        HSLFSlideShow ppt = new HSLFSlideShow(slTests.openResourceAsStream("basic_test_ppt_file.ppt"));
-
-        assertEquals(2, ppt.getSlides().size());
-
-        // First slide is 256 / 4
-        HSLFSlide s1 = ppt.getSlides().get(0);
-        assertEquals(256, s1._getSheetNumber());
-        assertEquals(4, s1._getSheetRefId());
-
-        // Last slide is 257 / 6
-        HSLFSlide s2 = ppt.getSlides().get(1);
-        assertEquals(257, s2._getSheetNumber());
-        assertEquals(6, s2._getSheetRefId());
-
-        // Add another slide, goes in at the end
-        HSLFSlide s3 = ppt.createSlide();
-        assertEquals(3, ppt.getSlides().size());
-        assertEquals(258, s3._getSheetNumber());
-        assertEquals(8, s3._getSheetRefId());
-
-
-        // Serialize and read again
-         ByteArrayOutputStream out = new ByteArrayOutputStream();
-        ppt.write(out);
-        out.close();
-
-        ppt = new HSLFSlideShow(new HSLFSlideShowImpl(new ByteArrayInputStream(out.toByteArray())));
-        assertEquals(3, ppt.getSlides().size());
-
-
-        // Check IDs are still right
-        s1 = ppt.getSlides().get(0);
-        assertEquals(256, s1._getSheetNumber());
-        assertEquals(4, s1._getSheetRefId());
-        s2 = ppt.getSlides().get(1);
-        assertEquals(257, s2._getSheetNumber());
-        assertEquals(6, s2._getSheetRefId());
-        s3 = ppt.getSlides().get(2);
-        assertEquals(3, ppt.getSlides().size());
-        assertEquals(258, s3._getSheetNumber());
-        assertEquals(8, s3._getSheetRefId());
+        try (HSLFSlideShow ppt1 = getSlideShow("basic_test_ppt_file.ppt")) {
+
+            assertEquals(2, ppt1.getSlides().size());
+
+            // First slide is 256 / 4
+            HSLFSlide s1 = ppt1.getSlides().get(0);
+            assertEquals(256, s1._getSheetNumber());
+            assertEquals(4, s1._getSheetRefId());
+
+            // Last slide is 257 / 6
+            HSLFSlide s2 = ppt1.getSlides().get(1);
+            assertEquals(257, s2._getSheetNumber());
+            assertEquals(6, s2._getSheetRefId());
+
+            // Add another slide, goes in at the end
+            HSLFSlide s3 = ppt1.createSlide();
+            assertEquals(3, ppt1.getSlides().size());
+            assertEquals(258, s3._getSheetNumber());
+            assertEquals(8, s3._getSheetRefId());
+
+            // Serialize and read again
+            try (HSLFSlideShow ppt2 = writeOutAndReadBack(ppt1)) {
+                assertEquals(3, ppt2.getSlides().size());
+
+                // Check IDs are still right
+                s1 = ppt2.getSlides().get(0);
+                assertEquals(256, s1._getSheetNumber());
+                assertEquals(4, s1._getSheetRefId());
+                s2 = ppt2.getSlides().get(1);
+                assertEquals(257, s2._getSheetNumber());
+                assertEquals(6, s2._getSheetRefId());
+                s3 = ppt2.getSlides().get(2);
+                assertEquals(3, ppt2.getSlides().size());
+                assertEquals(258, s3._getSheetNumber());
+                assertEquals(8, s3._getSheetRefId());
+            }
+        }
     }
-
 }
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hslf/model/TestTable.java b/poi-scratchpad/src/test/java/org/apache/poi/hslf/model/TestTable.java
index 1777ffed2c..b97dcef413 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hslf/model/TestTable.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hslf/model/TestTable.java
@@ -17,18 +17,17 @@
 
 package org.apache.poi.hslf.model;
 
+import static org.apache.poi.hslf.HSLFTestDataSamples.getSlideShow;
+import static org.apache.poi.hslf.HSLFTestDataSamples.writeOutAndReadBack;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertSame;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.util.List;
 
-import org.apache.poi.POIDataSamples;
 import org.apache.poi.hslf.usermodel.HSLFShape;
 import org.apache.poi.hslf.usermodel.HSLFSlide;
 import org.apache.poi.hslf.usermodel.HSLFSlideShow;
@@ -42,18 +41,15 @@ import org.apache.poi.sl.usermodel.TextShape.TextPlaceholder;
 import org.junit.jupiter.api.Test;
 
 /**
- * Test <code>Table</code> object.
+ * Test {@code Table} object.
  */
 public final class TestTable {
-    private static final POIDataSamples _slTests = POIDataSamples.getSlideShowInstance();
-
     /**
-     * Test that ShapeFactory works properly and returns <code>Table</code>
+     * Test that ShapeFactory works properly and returns {@code Table}
      */
     @Test
     void testShapeFactory() throws IOException {
         final int noColumns, noRows;
-        ByteArrayOutputStream out = new ByteArrayOutputStream();
         try (HSLFSlideShow ppt = new HSLFSlideShow()) {
             HSLFSlide slide = ppt.createSlide();
 
@@ -73,16 +69,15 @@ public final class TestTable {
             assertEquals(noColumns, tbl2.getNumberOfColumns());
             assertEquals(noRows, tbl2.getNumberOfRows());
 
-            ppt.write(out);
+            try (HSLFSlideShow ppt2 = writeOutAndReadBack(ppt)) {
+                HSLFSlide slide2 = ppt2.getSlides().get(0);
+                assertTrue(slide2.getShapes().get(0) instanceof HSLFTable);
+                HSLFTable tbl3 = (HSLFTable) slide2.getShapes().get(0);
+                assertEquals(noColumns, tbl3.getNumberOfColumns());
+                assertEquals(noRows, tbl3.getNumberOfRows());
+            }
         }
 
-        try (HSLFSlideShow ppt = new HSLFSlideShow(new ByteArrayInputStream(out.toByteArray()))) {
-            HSLFSlide slide = ppt.getSlides().get(0);
-            assertTrue(slide.getShapes().get(0) instanceof HSLFTable);
-            HSLFTable tbl3 = (HSLFTable) slide.getShapes().get(0);
-            assertEquals(noColumns, tbl3.getNumberOfColumns());
-            assertEquals(noRows, tbl3.getNumberOfRows());
-        }
     }
 
     /**
@@ -132,7 +127,7 @@ public final class TestTable {
      */
     @Test
     void test57820() throws IOException {
-        try (SlideShow<?,?> ppt = new HSLFSlideShow(_slTests.openResourceAsStream("bug57820-initTableNullRefrenceException.ppt"))) {
+        try (SlideShow<?,?> ppt = getSlideShow("bug57820-initTableNullRefrenceException.ppt")) {
 
             List<? extends Slide<?, ?>> slides = ppt.getSlides();
             assertEquals(1, slides.size());
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hslf/model/TestTextRunReWrite.java b/poi-scratchpad/src/test/java/org/apache/poi/hslf/model/TestTextRunReWrite.java
index f6f7fe6f7c..9509ca6c94 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hslf/model/TestTextRunReWrite.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hslf/model/TestTextRunReWrite.java
@@ -17,22 +17,20 @@
 
 package org.apache.poi.hslf.model;
 
+import static org.apache.poi.POIDataSamples.writeOutAndReadBack;
+import static org.apache.poi.hslf.HSLFTestDataSamples.getSlideShow;
 import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.util.List;
 
-import org.apache.poi.POIDataSamples;
 import org.apache.poi.hslf.usermodel.HSLFSlideShow;
 import org.apache.poi.hslf.usermodel.HSLFTextParagraph;
 import org.apache.poi.hslf.usermodel.HSLFTextRun;
 import org.apache.poi.poifs.filesystem.DirectoryNode;
 import org.apache.poi.poifs.filesystem.DocumentEntry;
 import org.apache.poi.poifs.filesystem.POIFSFileSystem;
-import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
 /**
@@ -41,137 +39,111 @@ import org.junit.jupiter.api.Test;
  *  that we don't break anything in the process.
  */
 public final class TestTextRunReWrite {
-	// HSLFSlideShow primed on the test data
-	private HSLFSlideShow ss;
-
-	/**
-	 * Load up a test PPT file with rich data
-	 */
-	@BeforeEach
-    void setUp() throws Exception {
-        POIDataSamples slTests = POIDataSamples.getSlideShowInstance();
-		String filename = "Single_Coloured_Page_With_Fonts_and_Alignments.ppt";
-		ss = new HSLFSlideShow(slTests.openResourceAsStream(filename));
-    }
-
     @Test
 	void testWritesOutTheSameNonRich() throws IOException {
-    	// Ensure the text lengths are as we'd expect to start with
-    	assertEquals(1, ss.getSlides().size());
-    	assertEquals(2, ss.getSlides().get(0).getTextParagraphs().size());
-
-        // Grab the first text run on the first sheet
-        List<HSLFTextParagraph> tr1 = ss.getSlides().get(0).getTextParagraphs().get(0);
-        List<HSLFTextParagraph> tr2 = ss.getSlides().get(0).getTextParagraphs().get(1);
-
-
-    	assertEquals(30, HSLFTextParagraph.getRawText(tr1).length());
-    	assertEquals(179, HSLFTextParagraph.getRawText(tr2).length());
-
-    	assertEquals(1, tr1.size());
-    	assertEquals(30, HSLFTextParagraph.getText(tr1).length());
-    	assertEquals(30, HSLFTextParagraph.getRawText(tr1).length());
-    	assertEquals(31, tr1.get(0).getTextRuns().get(0).getCharacterStyle().getCharactersCovered());
-    	assertEquals(31, tr1.get(0).getParagraphStyle().getCharactersCovered());
-
-    	// Set the text to be as it is now
-    	HSLFTextParagraph.setText(tr1, HSLFTextParagraph.getRawText(tr1));
-    	tr1 = ss.getSlides().get(0).getTextParagraphs().get(0);
-
-    	// Check the text lengths are still right
-    	assertEquals(30, HSLFTextParagraph.getRawText(tr1).length());
-    	assertEquals(179, HSLFTextParagraph.getRawText(tr2).length());
-
-        assertEquals(1, tr1.size());
-        assertEquals(30, HSLFTextParagraph.getText(tr1).length());
-        assertEquals(30, HSLFTextParagraph.getRawText(tr1).length());
-        assertEquals(31, tr1.get(0).getTextRuns().get(0).getCharacterStyle().getCharactersCovered());
-        assertEquals(31, tr1.get(0).getParagraphStyle().getCharactersCovered());
-
-
-		// Write the slideshow out to a byte array
-		ByteArrayOutputStream baos = new ByteArrayOutputStream();
-		ss.write(baos);
-
-		// Build an input stream of it
-		ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
-
-		// Use POIFS to query that lot
-		POIFSFileSystem npfs = new POIFSFileSystem(bais);
-
-		// Check that the "PowerPoint Document" sections have the same size
-		DirectoryNode oDir = ss.getSlideShowImpl().getDirectory();
-
-		DocumentEntry oProps = (DocumentEntry)oDir.getEntry(HSLFSlideShow.POWERPOINT_DOCUMENT);
-		DocumentEntry nProps = (DocumentEntry)npfs.getRoot().getEntry(HSLFSlideShow.POWERPOINT_DOCUMENT);
-		assertEquals(oProps.getSize(),nProps.getSize());
-
-		// Check that they contain the same data
-		byte[] _oData = new byte[oProps.getSize()];
-		byte[] _nData = new byte[nProps.getSize()];
-		oDir.createDocumentInputStream(HSLFSlideShow.POWERPOINT_DOCUMENT).read(_oData);
-		npfs.createDocumentInputStream(HSLFSlideShow.POWERPOINT_DOCUMENT).read(_nData);
-		assertArrayEquals(_oData, _nData);
-
-		npfs.close();
+		try (HSLFSlideShow ppt1 = getSlideShow("Single_Coloured_Page_With_Fonts_and_Alignments.ppt")) {
+			// Ensure the text lengths are as we'd expect to start with
+			assertEquals(1, ppt1.getSlides().size());
+			assertEquals(2, ppt1.getSlides().get(0).getTextParagraphs().size());
+
+			// Grab the first text run on the first sheet
+			List<HSLFTextParagraph> tr1 = ppt1.getSlides().get(0).getTextParagraphs().get(0);
+			List<HSLFTextParagraph> tr2 = ppt1.getSlides().get(0).getTextParagraphs().get(1);
+
+
+			assertEquals(30, HSLFTextParagraph.getRawText(tr1).length());
+			assertEquals(179, HSLFTextParagraph.getRawText(tr2).length());
+
+			assertEquals(1, tr1.size());
+			assertEquals(30, HSLFTextParagraph.getText(tr1).length());
+			assertEquals(30, HSLFTextParagraph.getRawText(tr1).length());
+			assertEquals(31, tr1.get(0).getTextRuns().get(0).getCharacterStyle().getCharactersCovered());
+			assertEquals(31, tr1.get(0).getParagraphStyle().getCharactersCovered());
+
+			// Set the text to be as it is now
+			HSLFTextParagraph.setText(tr1, HSLFTextParagraph.getRawText(tr1));
+			tr1 = ppt1.getSlides().get(0).getTextParagraphs().get(0);
+
+			// Check the text lengths are still right
+			assertEquals(30, HSLFTextParagraph.getRawText(tr1).length());
+			assertEquals(179, HSLFTextParagraph.getRawText(tr2).length());
+
+			assertEquals(1, tr1.size());
+			assertEquals(30, HSLFTextParagraph.getText(tr1).length());
+			assertEquals(30, HSLFTextParagraph.getRawText(tr1).length());
+			assertEquals(31, tr1.get(0).getTextRuns().get(0).getCharacterStyle().getCharactersCovered());
+			assertEquals(31, tr1.get(0).getParagraphStyle().getCharactersCovered());
+
+			// Use POIFS to query that lot
+			try (POIFSFileSystem npfs = writeOutAndReadBack(ppt1.getDirectory().getFileSystem())) {
+				// Check that the "PowerPoint Document" sections have the same size
+				DirectoryNode oDir = ppt1.getSlideShowImpl().getDirectory();
+
+				DocumentEntry oProps = (DocumentEntry) oDir.getEntry(HSLFSlideShow.POWERPOINT_DOCUMENT);
+				DocumentEntry nProps = (DocumentEntry) npfs.getRoot().getEntry(HSLFSlideShow.POWERPOINT_DOCUMENT);
+				assertEquals(oProps.getSize(), nProps.getSize());
+
+				// Check that they contain the same data
+				byte[] _oData = new byte[oProps.getSize()];
+				byte[] _nData = new byte[nProps.getSize()];
+				int oLen = oDir.createDocumentInputStream(HSLFSlideShow.POWERPOINT_DOCUMENT).read(_oData);
+				int nLen = npfs.createDocumentInputStream(HSLFSlideShow.POWERPOINT_DOCUMENT).read(_nData);
+				assertEquals(_oData.length, oLen);
+				assertEquals(_nData.length, nLen);
+				assertArrayEquals(_oData, _nData);
+			}
+		}
 	}
 
     @Test
     void testWritesOutTheSameRich() throws IOException {
-    	// Grab the first text run on the first sheet
-    	List<HSLFTextParagraph> tr1 = ss.getSlides().get(0).getTextParagraphs().get(0);
-
-    	// Get the first rich text run
-    	HSLFTextRun rtr1 = tr1.get(0).getTextRuns().get(0);
-
-
-    	// Check that the text sizes are as expected
-    	assertEquals(1, tr1.get(0).getTextRuns().size());
-        assertEquals(30, HSLFTextParagraph.getRawText(tr1).length());
-    	assertEquals(30, rtr1.getLength());
-    	assertEquals(30, rtr1.getRawText().length());
-    	assertEquals(31, rtr1.getCharacterStyle().getCharactersCovered());
-    	assertEquals(31, tr1.get(0).getParagraphStyle().getCharactersCovered());
-
-    	// Set the text to be as it is now
-    	rtr1.setText( rtr1.getRawText() );
-    	rtr1 = tr1.get(0).getTextRuns().get(0);
-
-    	// Check that the text sizes are still as expected
-    	assertEquals(1, tr1.get(0).getTextRuns().size());
-    	assertEquals(30, HSLFTextParagraph.getRawText(tr1).length());
-    	assertEquals(30, tr1.get(0).getTextRuns().get(0).getRawText().length());
-    	assertEquals(30, rtr1.getLength());
-    	assertEquals(30, rtr1.getRawText().length());
-    	assertEquals(31, rtr1.getCharacterStyle().getCharactersCovered());
-    	assertEquals(31, tr1.get(0).getParagraphStyle().getCharactersCovered());
-
-
-		// Write the slideshow out to a byte array
-		ByteArrayOutputStream baos = new ByteArrayOutputStream();
-		ss.write(baos);
-
-		// Build an input stream of it
-		ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
-
-		// Use POIFS to query that lot
-		POIFSFileSystem npfs = new POIFSFileSystem(bais);
-
-		// Check that the "PowerPoint Document" sections have the same size
-        DirectoryNode oDir = ss.getSlideShowImpl().getDirectory();
-
-		DocumentEntry oProps = (DocumentEntry)oDir.getEntry(HSLFSlideShow.POWERPOINT_DOCUMENT);
-		DocumentEntry nProps = (DocumentEntry)npfs.getRoot().getEntry(HSLFSlideShow.POWERPOINT_DOCUMENT);
-		assertEquals(oProps.getSize(),nProps.getSize());
-
-		// Check that they contain the same data
-		byte[] _oData = new byte[oProps.getSize()];
-		byte[] _nData = new byte[nProps.getSize()];
-
-		oDir.createDocumentInputStream(HSLFSlideShow.POWERPOINT_DOCUMENT).read(_oData);
-		npfs.createDocumentInputStream(HSLFSlideShow.POWERPOINT_DOCUMENT).read(_nData);
-		assertArrayEquals(_oData, _nData);
-
-		npfs.close();
+		try (HSLFSlideShow ppt1 = getSlideShow("Single_Coloured_Page_With_Fonts_and_Alignments.ppt")) {
+			// Grab the first text run on the first sheet
+			List<HSLFTextParagraph> tr1 = ppt1.getSlides().get(0).getTextParagraphs().get(0);
+
+			// Get the first rich text run
+			HSLFTextRun rtr1 = tr1.get(0).getTextRuns().get(0);
+
+			// Check that the text sizes are as expected
+			assertEquals(1, tr1.get(0).getTextRuns().size());
+			assertEquals(30, HSLFTextParagraph.getRawText(tr1).length());
+			assertEquals(30, rtr1.getLength());
+			assertEquals(30, rtr1.getRawText().length());
+			assertEquals(31, rtr1.getCharacterStyle().getCharactersCovered());
+			assertEquals(31, tr1.get(0).getParagraphStyle().getCharactersCovered());
+
+			// Set the text to be as it is now
+			rtr1.setText(rtr1.getRawText());
+			rtr1 = tr1.get(0).getTextRuns().get(0);
+
+			// Check that the text sizes are still as expected
+			assertEquals(1, tr1.get(0).getTextRuns().size());
+			assertEquals(30, HSLFTextParagraph.getRawText(tr1).length());
+			assertEquals(30, tr1.get(0).getTextRuns().get(0).getRawText().length());
+			assertEquals(30, rtr1.getLength());
+			assertEquals(30, rtr1.getRawText().length());
+			assertEquals(31, rtr1.getCharacterStyle().getCharactersCovered());
+			assertEquals(31, tr1.get(0).getParagraphStyle().getCharactersCovered());
+
+			// Use POIFS to query that lot
+			try (POIFSFileSystem npfs = writeOutAndReadBack(ppt1.getDirectory().getFileSystem())) {
+				// Check that the "PowerPoint Document" sections have the same size
+				DirectoryNode oDir = ppt1.getSlideShowImpl().getDirectory();
+
+				DocumentEntry oProps = (DocumentEntry) oDir.getEntry(HSLFSlideShow.POWERPOINT_DOCUMENT);
+				DocumentEntry nProps = (DocumentEntry) npfs.getRoot().getEntry(HSLFSlideShow.POWERPOINT_DOCUMENT);
+				assertEquals(oProps.getSize(), nProps.getSize());
+
+				// Check that they contain the same data
+				byte[] _oData = new byte[oProps.getSize()];
+				byte[] _nData = new byte[nProps.getSize()];
+
+				int oLen = oDir.createDocumentInputStream(HSLFSlideShow.POWERPOINT_DOCUMENT).read(_oData);
+				int nLen = npfs.createDocumentInputStream(HSLFSlideShow.POWERPOINT_DOCUMENT).read(_nData);
+				assertEquals(_oData.length, oLen);
+				assertEquals(_nData.length, nLen);
+				assertArrayEquals(_oData, _nData);
+			}
+		}
 	}
 }
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestAnimationInfoAtom.java b/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestAnimationInfoAtom.java
index 21d25007db..dac20b569b 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestAnimationInfoAtom.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestAnimationInfoAtom.java
@@ -23,8 +23,7 @@ import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import java.io.ByteArrayOutputStream;
-
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.junit.jupiter.api.Test;
 
 /**
@@ -66,7 +65,7 @@ public final class TestAnimationInfoAtom {
     @Test
     void testWrite() throws Exception {
         AnimationInfoAtom record = new AnimationInfoAtom(data, 0, data.length);
-        ByteArrayOutputStream baos = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
         record.writeOut(baos);
         byte[] b = baos.toByteArray();
 
@@ -82,7 +81,7 @@ public final class TestAnimationInfoAtom {
         record.setFlag(AnimationInfoAtom.Play, true);
         record.setFlag(AnimationInfoAtom.Synchronous, true);
 
-        ByteArrayOutputStream baos = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
         record.writeOut(baos);
         byte[] b = baos.toByteArray();
 
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestCString.java b/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestCString.java
index a117037832..054b5c9790 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestCString.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestCString.java
@@ -18,11 +18,11 @@
 package org.apache.poi.hslf.record;
 
 
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
 
-import java.io.ByteArrayOutputStream;
-
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.junit.jupiter.api.Test;
 
 /**
@@ -70,24 +70,16 @@ public final class TestCString {
 	@Test
 	void testWrite() throws Exception {
 		CString ca = new CString(data_a, 0, data_a.length);
-		ByteArrayOutputStream baos = new ByteArrayOutputStream();
+		UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
 		ca.writeOut(baos);
 		byte[] b = baos.toByteArray();
-
-		assertEquals(data_a.length, b.length);
-		for(int i=0; i<data_a.length; i++) {
-			assertEquals(data_a[i],b[i]);
-		}
+		assertArrayEquals(data_a, b);
 
 		CString cb = new CString(data_b, 0, data_a.length);
-		ByteArrayOutputStream baosB = new ByteArrayOutputStream();
+		UnsynchronizedByteArrayOutputStream baosB = new UnsynchronizedByteArrayOutputStream();
 		cb.writeOut(baosB);
 		b = baosB.toByteArray();
-
-		assertEquals(data_b.length, b.length);
-		for(int i=0; i<data_b.length; i++) {
-			assertEquals(data_b[i],b[i]);
-		}
+		assertArrayEquals(data_b, b);
 	}
 
 	// Turn data_a into data_b
@@ -107,14 +99,9 @@ public final class TestCString {
 		}
 		assertFalse(equals, "Arrays should not be equals");
 
-		ByteArrayOutputStream baos = new ByteArrayOutputStream();
+		UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
 		ca.writeOut(baos);
 		byte[] b = baos.toByteArray();
-
-		// Should now be the same
-		assertEquals(data_b.length, b.length);
-		for(int i=0; i<data_b.length; i++) {
-			assertEquals(data_b[i],b[i]);
-		}
+		assertArrayEquals(data_b, b);
 	}
 }
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestColorSchemeAtom.java b/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestColorSchemeAtom.java
index 768ca20623..fc74f17613 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestColorSchemeAtom.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestColorSchemeAtom.java
@@ -18,10 +18,10 @@
 package org.apache.poi.hslf.record;
 
 
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
-import java.io.ByteArrayOutputStream;
-
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.junit.jupiter.api.Test;
 
 /**
@@ -81,13 +81,10 @@ public final class TestColorSchemeAtom {
 	@Test
 	void testWrite() throws Exception {
 		ColorSchemeAtom csa = new ColorSchemeAtom(data_a,0,data_a.length);
-		ByteArrayOutputStream baos = new ByteArrayOutputStream();
+		UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
 		csa.writeOut(baos);
 		byte[] b = baos.toByteArray();
 
-		assertEquals(data_a.length, b.length);
-		for(int i=0; i<data_a.length; i++) {
-			assertEquals(data_a[i],b[i]);
-		}
+		assertArrayEquals(data_a, b);
 	}
 }
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestComment2000.java b/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestComment2000.java
index f518b9ffee..ffff00f289 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestComment2000.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestComment2000.java
@@ -18,16 +18,17 @@
 package org.apache.poi.hslf.record;
 
 
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertNull;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import java.io.ByteArrayOutputStream;
 import java.text.SimpleDateFormat;
 import java.util.Date;
 import java.util.Locale;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.util.LocaleUtil;
 import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.Test;
@@ -143,14 +144,10 @@ public final class TestComment2000 {
     @Test
     void testWrite() throws Exception {
 		Comment2000 ca = new Comment2000(data_a, 0, data_a.length);
-		ByteArrayOutputStream baos = new ByteArrayOutputStream();
+		UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
 		ca.writeOut(baos);
 		byte[] b = baos.toByteArray();
-
-		assertEquals(data_a.length, b.length);
-		for(int i=0; i<data_a.length; i++) {
-			assertEquals(data_a[i],b[i]);
-		}
+		assertArrayEquals(data_a, b);
 	}
 
 	// Change a few things
@@ -199,22 +196,16 @@ public final class TestComment2000 {
 		assertFalse(equals, "Arrays should not be equals");
 
 		// Check bytes are now the same
-		ByteArrayOutputStream baosa = new ByteArrayOutputStream();
-		ByteArrayOutputStream baosn = new ByteArrayOutputStream();
+		UnsynchronizedByteArrayOutputStream baosa = new UnsynchronizedByteArrayOutputStream();
+		UnsynchronizedByteArrayOutputStream baosn = new UnsynchronizedByteArrayOutputStream();
 		ca.writeOut(baosa);
 		cn.writeOut(baosn);
 		byte[] ba = baosa.toByteArray();
 		byte[] bn = baosn.toByteArray();
 
 		// Should now be the same
-		assertEquals(data_b.length, ba.length);
-		for(int i=0; i<data_b.length; i++) {
-			assertEquals(data_b[i],ba[i]);
-		}
-		assertEquals(data_b.length, bn.length);
-		for(int i=0; i<data_b.length; i++) {
-			assertEquals(data_b[i],bn[i]);
-		}
+		assertArrayEquals(data_b, ba);
+		assertArrayEquals(data_b, bn);
 	}
 
     /**
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestComment2000Atom.java b/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestComment2000Atom.java
index 59660e4947..f3bbdcaa8f 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestComment2000Atom.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestComment2000Atom.java
@@ -18,13 +18,14 @@
 package org.apache.poi.hslf.record;
 
 
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
-import java.io.ByteArrayOutputStream;
 import java.text.SimpleDateFormat;
 import java.util.Date;
 import java.util.Locale;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.util.LocaleUtil;
 import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.Test;
@@ -35,18 +36,18 @@ import org.junit.jupiter.api.Test;
 public final class TestComment2000Atom {
 	// From a real file
 	private final byte[] data_a = new byte[] {
-		00, 00, 0xE1-256, 0x2E, 0x1C, 00, 00, 00,
-		01, 00, 00, 00, 0xD6-256, 07, 01, 00,
-		02, 00, 0x18, 00, 0x0A, 00, 0x1A, 00,
-		0x0F, 00, 0xCD-256, 00, 0x92-256, 00,
-		00,	00, 0x92-256, 00, 00, 00
+		0, 0, 0xE1-256, 0x2E, 0x1C, 0, 0, 0,
+		1, 0, 0, 0, 0xD6-256, 7, 1, 0,
+		2, 0, 0x18, 0, 0x0A, 0, 0x1A, 0,
+		0x0F, 0, 0xCD-256, 0, 0x92-256, 0,
+		0,	0, 0x92-256, 0, 0, 0
 	};
 	private final byte[] data_b = new byte[] {
-		00, 00, 0xE1-256, 0x2E, 0x1C, 00, 00, 00,
-		05, 00, 00, 00, 0xD6-256, 0x07, 01, 00,
-		02, 00, 0x18, 00, 0x15, 00, 0x19, 00, 03,
-		00, 0xD5-256, 02, 0x0A, 00, 00, 00,
-		0x0E, 00, 00, 00
+		0, 0, 0xE1-256, 0x2E, 0x1C, 0, 0, 0,
+		5, 0, 0, 0, 0xD6-256, 0x07, 1, 0,
+		2, 0, 0x18, 0, 0x15, 0, 0x19, 0, 3,
+		0, 0xD5-256, 2, 0x0A, 0, 0, 0,
+		0x0E, 0, 0, 0
 		};
 
     private static SimpleDateFormat sdf;
@@ -60,7 +61,7 @@ public final class TestComment2000Atom {
 	@Test
 	void testRecordType() {
 		Comment2000Atom ca = new Comment2000Atom(data_a, 0, data_a.length);
-		assertEquals(12001l, ca.getRecordType());
+		assertEquals(12001L, ca.getRecordType());
 	}
 
 	@Test
@@ -105,14 +106,10 @@ public final class TestComment2000Atom {
 	@Test
     void testWrite() throws Exception {
 		Comment2000Atom ca = new Comment2000Atom(data_a, 0, data_a.length);
-		ByteArrayOutputStream baos = new ByteArrayOutputStream();
+		UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
 		ca.writeOut(baos);
 		byte[] b = baos.toByteArray();
-
-		assertEquals(data_a.length, b.length);
-		for(int i=0; i<data_a.length; i++) {
-			assertEquals(data_a[i],b[i]);
-		}
+		assertArrayEquals(data_a, b);
 	}
 
 	// Create A from scratch
@@ -130,14 +127,10 @@ public final class TestComment2000Atom {
 		a.setDate(date_a);
 
 		// Check it's now the same as a
-		ByteArrayOutputStream baos = new ByteArrayOutputStream();
+		UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
 		a.writeOut(baos);
 		byte[] b = baos.toByteArray();
-
-		assertEquals(data_a.length, b.length);
-		for(int i=0; i<data_a.length; i++) {
-			assertEquals(data_a[i],b[i]);
-		}
+		assertArrayEquals(data_a, b);
 	}
 
 	// Try to turn a into b
@@ -157,14 +150,9 @@ public final class TestComment2000Atom {
 		ca.setYOffset(0x0E);
 
 		// Check bytes are now the same
-		ByteArrayOutputStream baos = new ByteArrayOutputStream();
+		UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
 		ca.writeOut(baos);
 		byte[] b = baos.toByteArray();
-
-		// Should now be the same
-		assertEquals(data_b.length, b.length);
-		for(int i=0; i<data_b.length; i++) {
-			assertEquals(data_b[i],b[i]);
-		}
+		assertArrayEquals(data_b, b);
 	}
 }
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestCurrentUserAtom.java b/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestCurrentUserAtom.java
index 138e127024..b21e0d8b67 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestCurrentUserAtom.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestCurrentUserAtom.java
@@ -21,9 +21,9 @@ import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
-import java.io.ByteArrayOutputStream;
 import java.io.InputStream;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.POIDataSamples;
 import org.apache.poi.hslf.exceptions.EncryptedPowerPointFileException;
 import org.apache.poi.hslf.usermodel.HSLFSlideShowImpl;
@@ -89,7 +89,7 @@ public final class TestCurrentUserAtom {
 		cu.setCurrentEditOffset(0x2942);
 
 		// Check it matches
-		ByteArrayOutputStream baos = new ByteArrayOutputStream();
+		UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
 		cu.writeOut(baos);
 		byte[] out = baos.toByteArray();
 
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestDocumentAtom.java b/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestDocumentAtom.java
index 06bca9df9b..c831a478c6 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestDocumentAtom.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestDocumentAtom.java
@@ -23,8 +23,7 @@ import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import java.io.ByteArrayOutputStream;
-
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.junit.jupiter.api.Test;
 
 /**
@@ -41,7 +40,7 @@ public final class TestDocumentAtom {
 	@Test
     void testRecordType() {
 		DocumentAtom da = new DocumentAtom(data_a, 0, data_a.length);
-		assertEquals(1001l, da.getRecordType());
+		assertEquals(1001L, da.getRecordType());
 	}
 
 	@Test
@@ -67,7 +66,7 @@ public final class TestDocumentAtom {
 	void testSlideDetails() {
 		DocumentAtom da = new DocumentAtom(data_a, 0, data_a.length);
 		assertEquals(1, da.getFirstSlideNum());
-		assertEquals(0, da.getSlideSizeType());
+		assertEquals(DocumentAtom.SlideSize.ON_SCREEN, da.getSlideSizeTypeEnum());
 	}
 
 	@Test
@@ -82,7 +81,7 @@ public final class TestDocumentAtom {
 	@Test
 	void testWrite() throws Exception {
 		DocumentAtom da = new DocumentAtom(data_a, 0, data_a.length);
-		ByteArrayOutputStream baos = new ByteArrayOutputStream();
+		UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
 		da.writeOut(baos);
 		assertArrayEquals(data_a, baos.toByteArray());
 	}
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestDocumentEncryption.java b/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestDocumentEncryption.java
index 55944a5246..34945764f2 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestDocumentEncryption.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestDocumentEncryption.java
@@ -23,12 +23,12 @@ import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
+import java.io.InputStream;
 import java.security.MessageDigest;
 import java.util.List;
 
 import org.apache.commons.codec.binary.Base64;
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.POIDataSamples;
 import org.apache.poi.hpsf.DocumentSummaryInformation;
 import org.apache.poi.hpsf.PropertySet;
@@ -44,7 +44,6 @@ import org.apache.poi.poifs.crypt.CryptoFunctions;
 import org.apache.poi.poifs.crypt.EncryptionInfo;
 import org.apache.poi.poifs.crypt.HashAlgorithm;
 import org.apache.poi.poifs.crypt.cryptoapi.CryptoAPIDecryptor;
-import org.apache.poi.poifs.crypt.cryptoapi.CryptoAPIEncryptionHeader;
 import org.apache.poi.poifs.filesystem.POIFSFileSystem;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.params.ParameterizedTest;
@@ -86,12 +85,12 @@ public class TestDocumentEncryption {
             DocumentEncryptionAtom documentEncryptionAtom = hss.getDocumentEncryptionAtom();
             assertNotNull(documentEncryptionAtom);
             EncryptionInfo ei = documentEncryptionAtom.getEncryptionInfo();
-            ((CryptoAPIEncryptionHeader) ei.getHeader()).setKeySize(0x78);
+            ei.getHeader().setKeySize(0x78);
 
-            ByteArrayOutputStream bos = new ByteArrayOutputStream();
+            UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream();
             hss.write(bos);
 
-            try (POIFSFileSystem fs2 = new POIFSFileSystem(new ByteArrayInputStream(bos.toByteArray()));
+            try (POIFSFileSystem fs2 = new POIFSFileSystem(bos.toInputStream());
                  HSLFSlideShowImpl hss2 = new HSLFSlideShowImpl(fs2)) {
                 List<HSLFPictureData> picsActual = hss2.getPictureData();
 
@@ -109,9 +108,9 @@ public class TestDocumentEncryption {
     void cryptoAPIEncryption() throws Exception {
         /* documents with multiple edits need to be normalized for encryption */
         String pptFile = "57272_corrupted_usereditatom.ppt";
-        ByteArrayOutputStream encrypted = new ByteArrayOutputStream();
-        ByteArrayOutputStream expected = new ByteArrayOutputStream();
-        ByteArrayOutputStream actual = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream encrypted = new UnsynchronizedByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream expected = new UnsynchronizedByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream actual = new UnsynchronizedByteArrayOutputStream();
         try {
             try (POIFSFileSystem fs = new POIFSFileSystem(slTests.getFile(pptFile), true);
                  HSLFSlideShowImpl hss = new HSLFSlideShowImpl(fs)) {
@@ -126,8 +125,9 @@ public class TestDocumentEncryption {
             }
 
             // decrypted
-            ByteArrayInputStream bis = new ByteArrayInputStream(encrypted.toByteArray());
-            try (POIFSFileSystem fs = new POIFSFileSystem(bis);
+
+            try (InputStream bis = encrypted.toInputStream();
+                 POIFSFileSystem fs = new POIFSFileSystem(bis);
                  HSLFSlideShowImpl hss = new HSLFSlideShowImpl(fs)) {
                 Biff8EncryptionKey.setCurrentUserPassword(null);
                 hss.write(actual);
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestExControl.java b/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestExControl.java
index c7bd84e116..2faa7ebfd8 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestExControl.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestExControl.java
@@ -22,8 +22,7 @@ import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 
-import java.io.ByteArrayOutputStream;
-
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.junit.jupiter.api.Test;
 
 /**
@@ -93,7 +92,7 @@ public final class TestExControl {
 	@Test
 	void testWrite() throws Exception {
 		ExControl record = new ExControl(data, 0, data.length);
-		ByteArrayOutputStream baos = new ByteArrayOutputStream();
+		UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
 		record.writeOut(baos);
 		assertArrayEquals(data, baos.toByteArray());
 	}
@@ -116,7 +115,7 @@ public final class TestExControl {
 		record.setProgId("ShockwaveFlash.ShockwaveFlash.9");
 		record.setClipboardName("Shockwave Flash Object");
 
-		ByteArrayOutputStream baos = new ByteArrayOutputStream();
+		UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
 		record.writeOut(baos);
 		assertArrayEquals(data, baos.toByteArray());
 	}
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestExHyperlink.java b/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestExHyperlink.java
index 13fea4a83a..42a9867560 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestExHyperlink.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestExHyperlink.java
@@ -22,11 +22,11 @@ import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.POIDataSamples;
 import org.apache.poi.hslf.usermodel.HSLFSlideShow;
 import org.apache.poi.hslf.usermodel.HSLFSlideShowImpl;
@@ -46,14 +46,14 @@ public final class TestExHyperlink {
 	    ExHyperlink exHyperlink = new ExHyperlink(exHyperlinkBytes, 0, exHyperlinkBytes.length);
 
 
-	    assertEquals(4055l, exHyperlink.getRecordType());
+	    assertEquals(4055L, exHyperlink.getRecordType());
         assertEquals(3, exHyperlink.getExHyperlinkAtom().getNumber());
         String expURL = "http://jakarta.apache.org/poi/hssf/";
         assertEquals(expURL, exHyperlink.getLinkURL());
         assertEquals(expURL, exHyperlink._getDetailsA());
         assertEquals(expURL, exHyperlink._getDetailsB());
 
-        ByteArrayOutputStream baos = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
         exHyperlink.writeOut(baos);
         assertArrayEquals(exHyperlinkBytes, baos.toByteArray());
 	}
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestExHyperlinkAtom.java b/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestExHyperlinkAtom.java
index fb8072bd44..f868d96b16 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestExHyperlinkAtom.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestExHyperlinkAtom.java
@@ -21,8 +21,7 @@ package org.apache.poi.hslf.record;
 import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
-import java.io.ByteArrayOutputStream;
-
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.junit.jupiter.api.Test;
 
 /**
@@ -57,7 +56,7 @@ public class TestExHyperlinkAtom {
 	@Test
 	void testWrite() throws Exception {
     	ExHyperlinkAtom eha = new ExHyperlinkAtom(data_a, 0, data_a.length);
-		ByteArrayOutputStream baos = new ByteArrayOutputStream();
+		UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
 		eha.writeOut(baos);
 		assertArrayEquals(data_a, baos.toByteArray());
 	}
@@ -71,7 +70,7 @@ public class TestExHyperlinkAtom {
 		eha.setNumber(1);
 
 		// Check it's now the same as a
-		ByteArrayOutputStream baos = new ByteArrayOutputStream();
+		UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
 		eha.writeOut(baos);
 		assertArrayEquals(data_a, baos.toByteArray());
 	}
@@ -85,7 +84,7 @@ public class TestExHyperlinkAtom {
 		eha.setNumber(4);
 
 		// Check bytes are now the same
-		ByteArrayOutputStream baos = new ByteArrayOutputStream();
+		UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
 		eha.writeOut(baos);
 		assertArrayEquals(data_b, baos.toByteArray());
 	}
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestExMediaAtom.java b/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestExMediaAtom.java
index 5b961d5816..606f0ac827 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestExMediaAtom.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestExMediaAtom.java
@@ -23,8 +23,7 @@ import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import java.io.ByteArrayOutputStream;
-
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.junit.jupiter.api.Test;
 
 /**
@@ -50,7 +49,7 @@ public final class TestExMediaAtom {
 	@Test
 	void testWrite() throws Exception {
 		ExMediaAtom record = new ExMediaAtom(data, 0, data.length);
-		ByteArrayOutputStream baos = new ByteArrayOutputStream();
+		UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
 		record.writeOut(baos);
 		byte[] b = baos.toByteArray();
 
@@ -68,7 +67,7 @@ public final class TestExMediaAtom {
 		record.setFlag(HeadersFootersAtom.fHasTodayDate, false);
 		record.setFlag(HeadersFootersAtom.fHasFooter, false);
 
-		ByteArrayOutputStream baos = new ByteArrayOutputStream();
+		UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
 		record.writeOut(baos);
 		byte[] b = baos.toByteArray();
 
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestExObjListAtom.java b/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestExObjListAtom.java
index 9256b01b9f..97d3ef1707 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestExObjListAtom.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestExObjListAtom.java
@@ -20,8 +20,7 @@ package org.apache.poi.hslf.record;
 
 import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 
-import java.io.ByteArrayOutputStream;
-
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.ss.formula.functions.BaseTestNumeric;
 import org.junit.jupiter.api.Test;
 
@@ -57,7 +56,7 @@ public class TestExObjListAtom {
 	@Test
 	void testWrite() throws Exception {
 		ExObjListAtom eoa = new ExObjListAtom(data_a, 0, data_a.length);
-		ByteArrayOutputStream baos = new ByteArrayOutputStream();
+		UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
 		eoa.writeOut(baos);
 		assertArrayEquals(data_a, baos.toByteArray());
 	}
@@ -71,7 +70,7 @@ public class TestExObjListAtom {
 		eoa.setObjectIDSeed(1);
 
 		// Check it's now the same as a
-		ByteArrayOutputStream baos = new ByteArrayOutputStream();
+		UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
 		eoa.writeOut(baos);
 		assertArrayEquals(data_a, baos.toByteArray());
 	}
@@ -85,7 +84,7 @@ public class TestExObjListAtom {
 		eoa.setObjectIDSeed(4);
 
 		// Check bytes are now the same
-		ByteArrayOutputStream baos = new ByteArrayOutputStream();
+		UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
 		eoa.writeOut(baos);
 		assertArrayEquals(data_b, baos.toByteArray());
 	}
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestExOleObjAtom.java b/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestExOleObjAtom.java
index 4c7771cac8..a0860abbbe 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestExOleObjAtom.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestExOleObjAtom.java
@@ -20,8 +20,7 @@ package org.apache.poi.hslf.record;
 import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
-import java.io.ByteArrayOutputStream;
-
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.junit.jupiter.api.Test;
 
 /**
@@ -50,7 +49,7 @@ public final class TestExOleObjAtom {
 	@Test
 	void testWrite() throws Exception {
 		ExOleObjAtom record = new ExOleObjAtom(data, 0, data.length);
-		ByteArrayOutputStream baos = new ByteArrayOutputStream();
+		UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
 		record.writeOut(baos);
 		assertArrayEquals(data, baos.toByteArray());
 	}
@@ -65,7 +64,7 @@ public final class TestExOleObjAtom {
 		record.setObjStgDataRef(2);
 		record.setOptions(1283584);
 
-		ByteArrayOutputStream baos = new ByteArrayOutputStream();
+		UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
 		record.writeOut(baos);
 		assertArrayEquals(data, baos.toByteArray());
 	}
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestExOleObjStg.java b/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestExOleObjStg.java
index fcdadfe211..f9d282a095 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestExOleObjStg.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestExOleObjStg.java
@@ -22,12 +22,12 @@ import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
-import java.io.InputStream;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.poifs.filesystem.DocumentEntry;
 import org.apache.poi.poifs.filesystem.POIFSFileSystem;
+import org.apache.poi.util.IOUtils;
 import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.Test;
 
@@ -58,7 +58,7 @@ public final class TestExOleObjStg {
         assertEquals(RecordTypes.ExOleObjStg.typeID, record.getRecordType());
 
         int len = record.getDataLength();
-        byte[] oledata = readAll(record.getData());
+        byte[] oledata = IOUtils.toByteArray(record.getData());
         assertEquals(len, oledata.length);
 
         try (POIFSFileSystem fs = new POIFSFileSystem(record.getData())) {
@@ -70,7 +70,7 @@ public final class TestExOleObjStg {
     @Test
     void testWrite() throws Exception {
         ExOleObjStg record = new ExOleObjStg(data, 0, data.length);
-        ByteArrayOutputStream baos = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
         record.writeOut(baos);
         byte[] b = baos.toByteArray();
 
@@ -80,7 +80,7 @@ public final class TestExOleObjStg {
     @Test
     void testNewRecord() throws Exception {
         ExOleObjStg src = new ExOleObjStg(data, 0, data.length);
-        byte[] oledata = readAll(src.getData());
+        byte[] oledata = IOUtils.toByteArray(src.getData());
 
         ExOleObjStg tgt = new ExOleObjStg();
         tgt.setData(oledata);
@@ -88,22 +88,11 @@ public final class TestExOleObjStg {
 
         assertEquals(src.getDataLength(), tgt.getDataLength());
 
-        ByteArrayOutputStream out = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream out = new UnsynchronizedByteArrayOutputStream();
         tgt.writeOut(out);
         byte[] b = out.toByteArray();
 
         assertEquals(data.length, b.length);
         assertArrayEquals(data, b);
     }
-
-    private byte[] readAll(InputStream is) throws IOException {
-        int pos;
-        byte[] chunk = new byte[1024];
-        ByteArrayOutputStream out = new  ByteArrayOutputStream();
-        while((pos = is.read(chunk)) > 0){
-            out.write(chunk, 0, pos);
-        }
-        return out.toByteArray();
-
-    }
 }
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestExVideoContainer.java b/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestExVideoContainer.java
index 3933965ac2..ce02202335 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestExVideoContainer.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestExVideoContainer.java
@@ -23,8 +23,7 @@ import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 
-import java.io.ByteArrayOutputStream;
-
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.junit.jupiter.api.Test;
 
 /**
@@ -68,7 +67,7 @@ public final class TestExVideoContainer {
     @Test
     void testWrite() throws Exception {
         ExVideoContainer record = new ExVideoContainer(data, 0, data.length);
-        ByteArrayOutputStream baos = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
         record.writeOut(baos);
         assertArrayEquals(data, baos.toByteArray());
     }
@@ -79,7 +78,7 @@ public final class TestExVideoContainer {
         record.getExMediaAtom().setObjectId(1);
         record.getPathAtom().setText("D:\\projects\\SchulerAG\\mcom_v_1_0_4\\view\\data\\tests\\images\\cards.mpg");
 
-        ByteArrayOutputStream baos = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
         record.writeOut(baos);
         assertArrayEquals(data, baos.toByteArray());
     }
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestFontCollection.java b/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestFontCollection.java
index f5b64da586..3592100af6 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestFontCollection.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestFontCollection.java
@@ -19,12 +19,13 @@ package org.apache.poi.hslf.record;
 
 import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertNull;
 
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.POIDataSamples;
 import org.apache.poi.hslf.usermodel.HSLFFontInfo;
 import org.apache.poi.hslf.usermodel.HSLFFontInfoPredefined;
@@ -78,16 +79,22 @@ public final class TestFontCollection {
         assertEquals(child.length, 3);
 
         // Check we get the right font name for the indicies
-        assertEquals("Times New Roman", fonts.getFontInfo(0).getTypeface());
-        assertEquals("Helvetica", fonts.getFontInfo(1).getTypeface());
-        assertEquals("Arial", fonts.getFontInfo(2).getTypeface());
+        fi = fonts.getFontInfo(0);
+        assertNotNull(fi);
+        assertEquals("Times New Roman", fi.getTypeface());
+        fi = fonts.getFontInfo(1);
+        assertNotNull(fi);
+        assertEquals("Helvetica", fi.getTypeface());
+        fi = fonts.getFontInfo(2);
+        assertNotNull(fi);
+        assertEquals("Arial", fi.getTypeface());
         assertNull(fonts.getFontInfo(3));
     }
 
     @Test
     void testWrite() throws Exception {
         FontCollection fonts = new FontCollection(data, 0, data.length);
-        ByteArrayOutputStream out = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream out = new UnsynchronizedByteArrayOutputStream();
         fonts.writeOut(out);
         byte[] recdata = out.toByteArray();
         assertArrayEquals(recdata, data);
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestHeadersFootersAtom.java b/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestHeadersFootersAtom.java
index 3edfadb3de..7277fc4790 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestHeadersFootersAtom.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestHeadersFootersAtom.java
@@ -23,8 +23,7 @@ import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import java.io.ByteArrayOutputStream;
-
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.junit.jupiter.api.Test;
 
 /**
@@ -55,7 +54,7 @@ public final class TestHeadersFootersAtom {
     @Test
 	void testWrite() throws Exception {
 		HeadersFootersAtom record = new HeadersFootersAtom(data, 0, data.length);
-		ByteArrayOutputStream baos = new ByteArrayOutputStream();
+		UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
 		record.writeOut(baos);
 		assertArrayEquals(data, baos.toByteArray());
 	}
@@ -67,7 +66,7 @@ public final class TestHeadersFootersAtom {
         record.setFlag(HeadersFootersAtom.fHasTodayDate, true);
         record.setFlag(HeadersFootersAtom.fHasFooter, true);
 
-        ByteArrayOutputStream baos = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
         record.writeOut(baos);
         assertArrayEquals(data, baos.toByteArray());
     }
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestHeadersFootersContainer.java b/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestHeadersFootersContainer.java
index f6a25739b2..5d6d15b798 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestHeadersFootersContainer.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestHeadersFootersContainer.java
@@ -23,8 +23,7 @@ import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertNull;
 
-import java.io.ByteArrayOutputStream;
-
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.junit.jupiter.api.Test;
 
 /**
@@ -76,7 +75,7 @@ public final class TestHeadersFootersContainer {
     @Test
 	void testWriteSlideHeadersFootersContainer() throws Exception {
 		HeadersFootersContainer record = new HeadersFootersContainer(slideData, 0, slideData.length);
-		ByteArrayOutputStream baos = new ByteArrayOutputStream();
+		UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
 		record.writeOut(baos);
 		assertArrayEquals(slideData, baos.toByteArray());
 	}
@@ -100,7 +99,7 @@ public final class TestHeadersFootersContainer {
         assertEquals(HeadersFootersContainer.FOOTERATOM, csFooter.getOptions() >> 4);
         csFooter.setText("My Footer - 1");
 
-        ByteArrayOutputStream baos = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
         record.writeOut(baos);
         assertArrayEquals(slideData, baos.toByteArray());
     }
@@ -129,7 +128,7 @@ public final class TestHeadersFootersContainer {
     @Test
 	void testWriteNotesHeadersFootersContainer() throws Exception {
 		HeadersFootersContainer record = new HeadersFootersContainer(notesData, 0, notesData.length);
-        ByteArrayOutputStream baos = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
 		record.writeOut(baos);
 		assertArrayEquals(notesData, baos.toByteArray());
 	}
@@ -161,7 +160,7 @@ public final class TestHeadersFootersContainer {
         assertEquals(HeadersFootersContainer.FOOTERATOM, csFooter.getOptions() >> 4);
         csFooter.setText("Note Footer");
 
-        ByteArrayOutputStream baos = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
         record.writeOut(baos);
         assertArrayEquals(notesData, baos.toByteArray());
     }
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestInteractiveInfo.java b/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestInteractiveInfo.java
index 7da5ee6f5c..1b1ab55491 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestInteractiveInfo.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestInteractiveInfo.java
@@ -24,8 +24,7 @@ package org.apache.poi.hslf.record;
 import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
-import java.io.ByteArrayOutputStream;
-
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.junit.jupiter.api.Test;
 
 /**
@@ -57,7 +56,7 @@ public class TestInteractiveInfo {
 	@Test
 	void testWrite() throws Exception {
 		InteractiveInfo ii = new InteractiveInfo(data_a, 0, data_a.length);
-		ByteArrayOutputStream baos = new ByteArrayOutputStream();
+		UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
 		ii.writeOut(baos);
 		assertArrayEquals(data_a, baos.toByteArray());
 	}
@@ -75,7 +74,7 @@ public class TestInteractiveInfo {
 		ia.setHyperlinkType((byte)8);
 
 		// Check it's now the same as a
-		ByteArrayOutputStream baos = new ByteArrayOutputStream();
+		UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
 		ii.writeOut(baos);
 		assertArrayEquals(data_a, baos.toByteArray());
    }
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestInteractiveInfoAtom.java b/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestInteractiveInfoAtom.java
index 7f9bcde86e..9eeab59618 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestInteractiveInfoAtom.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestInteractiveInfoAtom.java
@@ -21,8 +21,7 @@ package org.apache.poi.hslf.record;
 import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
-import java.io.ByteArrayOutputStream;
-
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.junit.jupiter.api.Test;
 
 /**
@@ -74,7 +73,7 @@ public class TestInteractiveInfoAtom {
 	@Test
 	void testWrite() throws Exception {
 		InteractiveInfoAtom ia = new InteractiveInfoAtom(data_a, 0, data_a.length);
-		ByteArrayOutputStream baos = new ByteArrayOutputStream();
+		UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
 		ia.writeOut(baos);
 		assertArrayEquals(data_a, baos.toByteArray());
 	}
@@ -91,7 +90,7 @@ public class TestInteractiveInfoAtom {
 		ia.setHyperlinkType((byte)8);
 
 		// Check it's now the same as a
-		ByteArrayOutputStream baos = new ByteArrayOutputStream();
+		UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
 		ia.writeOut(baos);
 		assertArrayEquals(data_a, baos.toByteArray());
 	}
@@ -105,7 +104,7 @@ public class TestInteractiveInfoAtom {
 		ia.setHyperlinkID(4);
 
 		// Check bytes are now the same
-		ByteArrayOutputStream baos = new ByteArrayOutputStream();
+		UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
 		ia.writeOut(baos);
 		assertArrayEquals(data_b, baos.toByteArray());
 	}
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestNotesAtom.java b/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestNotesAtom.java
index e2852088dc..d122f019dd 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestNotesAtom.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestNotesAtom.java
@@ -22,8 +22,7 @@ import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
 
-import java.io.ByteArrayOutputStream;
-
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.junit.jupiter.api.Test;
 
 /**
@@ -52,7 +51,7 @@ public final class TestNotesAtom {
 	@Test
 	void testWrite() throws Exception {
 		NotesAtom na = new NotesAtom(data_a, 0, data_a.length);
-		ByteArrayOutputStream baos = new ByteArrayOutputStream();
+		UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
 		na.writeOut(baos);
 		assertArrayEquals(data_a, baos.toByteArray());
 	}
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestSlideAtom.java b/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestSlideAtom.java
index ef3c7b84b4..7f67088716 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestSlideAtom.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestSlideAtom.java
@@ -22,9 +22,9 @@ import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.hslf.HSLFTestDataSamples;
 import org.apache.poi.hslf.record.SlideAtomLayout.SlideLayoutType;
 import org.apache.poi.hslf.usermodel.HSLFSlide;
@@ -43,7 +43,7 @@ public final class TestSlideAtom {
 	@Test
 	void testRecordType() {
 		SlideAtom sa = new SlideAtom(data_a, 0, data_a.length);
-		assertEquals(1007l, sa.getRecordType());
+		assertEquals(1007L, sa.getRecordType());
 	}
 
     @Test
@@ -75,23 +75,23 @@ public final class TestSlideAtom {
     @Test
 	void testWrite() throws IOException {
 		SlideAtom sa = new SlideAtom(data_a, 0, data_a.length);
-		ByteArrayOutputStream baos = new ByteArrayOutputStream();
+		UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
 		sa.writeOut(baos);
 		assertArrayEquals(data_a, baos.toByteArray());
 	}
 
     @Test
 	void testSSSlideInfoAtom() throws IOException {
-		HSLFSlideShow ss1 = new HSLFSlideShow();
-		HSLFSlide slide1 = ss1.createSlide(), slide2 = ss1.createSlide();
-		slide2.setHidden(true);
-
-		HSLFSlideShow ss2 = HSLFTestDataSamples.writeOutAndReadBack(ss1);
-		slide1 = ss2.getSlides().get(0);
-		slide2 = ss2.getSlides().get(1);
-		assertFalse(slide1.isHidden());
-		assertTrue(slide2.isHidden());
-		ss2.close();
-		ss1.close();
+		try (HSLFSlideShow ppt1 = new HSLFSlideShow()) {
+			HSLFSlide slide1 = ppt1.createSlide(), slide2 = ppt1.createSlide();
+			slide2.setHidden(true);
+
+			try (HSLFSlideShow ppt2 = HSLFTestDataSamples.writeOutAndReadBack(ppt1)) {
+				slide1 = ppt2.getSlides().get(0);
+				slide2 = ppt2.getSlides().get(1);
+				assertFalse(slide1.isHidden());
+				assertTrue(slide2.isHidden());
+			}
+		}
 	}
 }
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestSlidePersistAtom.java b/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestSlidePersistAtom.java
index 2a638d5a9a..d5f1105f47 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestSlidePersistAtom.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestSlidePersistAtom.java
@@ -22,8 +22,7 @@ import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import java.io.ByteArrayOutputStream;
-
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.junit.jupiter.api.Test;
 
 /**
@@ -53,7 +52,7 @@ public final class TestSlidePersistAtom {
 	@Test
 	void testWrite() throws Exception {
 		SlidePersistAtom spa = new SlidePersistAtom(data_a, 0, data_a.length);
-		ByteArrayOutputStream baos = new ByteArrayOutputStream();
+		UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
 		spa.writeOut(baos);
 		assertArrayEquals(data_a, baos.toByteArray());
 	}
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestStyleTextPropAtom.java b/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestStyleTextPropAtom.java
index 3de5c8d131..1e57798caf 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestStyleTextPropAtom.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestStyleTextPropAtom.java
@@ -26,15 +26,14 @@ import static org.junit.jupiter.api.Assertions.assertNull;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.util.List;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.hslf.exceptions.HSLFException;
 import org.apache.poi.hslf.model.textproperties.CharFlagsTextProp;
 import org.apache.poi.hslf.model.textproperties.TextProp;
 import org.apache.poi.hslf.model.textproperties.TextPropCollection;
-import org.apache.poi.util.HexDump;
 import org.junit.jupiter.api.Test;
 
 /**
@@ -467,14 +466,9 @@ public final class TestStyleTextPropAtom {
         tpc.setValue(0xFE0033FF);
 
         // Should now be the same as data_a
-        ByteArrayOutputStream baos = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
         stpa.writeOut(baos);
-        byte[] b = baos.toByteArray();
-
-        assertEquals(data_a.length, b.length);
-        for(int i=0; i<data_a.length; i++) {
-            assertEquals(data_a[i],b[i]);
-        }
+        assertArrayEquals(data_a, baos.toByteArray());
     }
 
     /**
@@ -621,34 +615,20 @@ public final class TestStyleTextPropAtom {
                     assertEquals(tpa.getValue(), tpb.getValue());
                 }
 
-                ByteArrayOutputStream ba = new ByteArrayOutputStream();
-                ByteArrayOutputStream bb = new ByteArrayOutputStream();
+                UnsynchronizedByteArrayOutputStream ba = new UnsynchronizedByteArrayOutputStream();
+                UnsynchronizedByteArrayOutputStream bb = new UnsynchronizedByteArrayOutputStream();
 
                 ca.writeOut(ba);
                 cb.writeOut(bb);
-                byte[] cab = ba.toByteArray();
-                byte[] cbb = bb.toByteArray();
 
-                assertEquals(cbb.length, cab.length);
-                for(int j=0; j<cab.length; j++) {
-                    //System.out.println("On tp " + z + " " + i + " " + j + "\t" + cab[j] + "\t" + cbb[j]);
-                    assertEquals(cbb[j], cab[j]);
-                }
+                assertArrayEquals(bb.toByteArray(), ba.toByteArray());
             }
         }
 
-
-
         // Check byte level with b
-        ByteArrayOutputStream baos = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
         stpa.writeOut(baos);
-        byte[] b = baos.toByteArray();
-
-        assertEquals(data_b.length, b.length);
-        for(int i=0; i<data_b.length; i++) {
-            //System.out.println(i + "\t" + b[i] + "\t" + data_b[i] + "\t" + Integer.toHexString(b[i]) );
-            assertEquals(data_b[i],b[i]);
-        }
+        assertArrayEquals(data_b, baos.toByteArray());
     }
 
     @Test
@@ -694,13 +674,9 @@ public final class TestStyleTextPropAtom {
         StyleTextPropAtom stpb = new StyleTextPropAtom(data, 0,data.length);
         if(textlen != -1) stpb.setParentTextSize(textlen);
 
-        ByteArrayOutputStream out = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream out = new UnsynchronizedByteArrayOutputStream();
         stpb.writeOut(out);
-        byte[] bytes = out.toByteArray();
-
-        assertEquals(expected.length, bytes.length);
-        assertArrayEquals(expected, bytes,
-            "Had: " + HexDump.toHex(expected) + "\nand: " + HexDump.toHex(bytes));
+        assertArrayEquals(expected, out.toByteArray());
     }
 
     @Test
@@ -759,12 +735,14 @@ public final class TestStyleTextPropAtom {
      *
      * From the test file attached to the bug:
      *
+     * {@code
      * <StyleTextPropAtom info="0" type="4001" size="94" offset="114782" header="00 00 A1 0F 5E 00 00 00 ">
      *   14 00 00 00 00 00 41 00 0A 00 06 00 50 00 07 00 01 00 00 00 00 00 00 00 02
      *   00 00 00 01 04 00 00 01 04 01 00 00 00 01 08 00 00 01 08 0C 00 00 00 01 0C
      *   00 00 01 0C 01 00 00 00 01 10 00 00 01 10 01 00 00 00 01 14 00 00 01 14 01
      *   00 00 00 01 18 00 00 01 18 01 00 00 00 01 1C 00 00 01 1C
      * </StyleTextPropAtom>
+     * }
      */
      @Test
     void test45815() throws IOException {
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestTextBytesAtom.java b/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestTextBytesAtom.java
index 44f2dc4617..c06eff77d1 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestTextBytesAtom.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestTextBytesAtom.java
@@ -21,9 +21,9 @@ package org.apache.poi.hslf.record;
 import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
-import java.io.ByteArrayOutputStream;
 import java.nio.charset.StandardCharsets;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.junit.jupiter.api.Test;
 
 /**
@@ -64,7 +64,7 @@ public final class TestTextBytesAtom {
 		TextBytesAtom tba = new TextBytesAtom(data,0,data.length);
 		tba.setText(alt_text.getBytes(StandardCharsets.ISO_8859_1));
 
-		ByteArrayOutputStream baos = new ByteArrayOutputStream();
+		UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
 		tba.writeOut(baos);
 		assertArrayEquals(alt_data, baos.toByteArray());
 	}
@@ -72,7 +72,7 @@ public final class TestTextBytesAtom {
 	@Test
 	void testWrite() throws Exception {
 		TextBytesAtom tba = new TextBytesAtom(data,0,data.length);
-		ByteArrayOutputStream baos = new ByteArrayOutputStream();
+		UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
 		tba.writeOut(baos);
 		assertArrayEquals(data, baos.toByteArray());
 	}
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestTextCharsAtom.java b/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestTextCharsAtom.java
index 4c1a71daa0..382719cdfc 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestTextCharsAtom.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestTextCharsAtom.java
@@ -21,8 +21,7 @@ package org.apache.poi.hslf.record;
 import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
-import java.io.ByteArrayOutputStream;
-
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.junit.jupiter.api.Test;
 
 /**
@@ -60,7 +59,7 @@ public final class TestTextCharsAtom {
 		TextCharsAtom tca = new TextCharsAtom(data,0,data.length);
 		tca.setText(alt_text);
 
-		ByteArrayOutputStream baos = new ByteArrayOutputStream();
+		UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
 		tca.writeOut(baos);
 		assertArrayEquals(alt_data, baos.toByteArray());
 	}
@@ -68,7 +67,7 @@ public final class TestTextCharsAtom {
 	@Test
 	void testWrite() throws Exception {
 		TextCharsAtom tca = new TextCharsAtom(data,0,data.length);
-		ByteArrayOutputStream baos = new ByteArrayOutputStream();
+		UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
 		tca.writeOut(baos);
 		assertArrayEquals(data, baos.toByteArray());
 	}
@@ -82,7 +81,7 @@ public final class TestTextCharsAtom {
 		assertEquals(data_text, tca.getText());
 
 		// Check it's now like data
-		ByteArrayOutputStream baos = new ByteArrayOutputStream();
+		UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
 		tca.writeOut(baos);
 		assertArrayEquals(data, baos.toByteArray());
 	}
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestTextHeaderAtom.java b/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestTextHeaderAtom.java
index 4935940afb..6eddf527af 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestTextHeaderAtom.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestTextHeaderAtom.java
@@ -21,8 +21,7 @@ package org.apache.poi.hslf.record;
 import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
-import java.io.ByteArrayOutputStream;
-
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.sl.usermodel.TextShape.TextPlaceholder;
 import org.junit.jupiter.api.Test;
 
@@ -54,7 +53,7 @@ public final class TestTextHeaderAtom {
 	@Test
 	void testWrite() throws Exception {
 		TextHeaderAtom tha = new TextHeaderAtom(notes_data,0,12);
-		ByteArrayOutputStream baos = new ByteArrayOutputStream();
+		UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
 		tha.writeOut(baos);
 		assertArrayEquals(notes_data, baos.toByteArray());
 	}
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestTextRulerAtom.java b/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestTextRulerAtom.java
index e50419c410..a24402ec2a 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestTextRulerAtom.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestTextRulerAtom.java
@@ -21,9 +21,9 @@ import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 
-import java.io.ByteArrayOutputStream;
 import java.util.List;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.hslf.model.textproperties.HSLFTabStop;
 import org.junit.jupiter.api.Test;
 
@@ -61,7 +61,7 @@ public final class TestTextRulerAtom {
     @Test
 	void testWriteRuler() throws Exception {
 		TextRulerAtom ruler = new TextRulerAtom(data_1, 0, data_1.length);
-		ByteArrayOutputStream out = new ByteArrayOutputStream();
+		UnsynchronizedByteArrayOutputStream out = new UnsynchronizedByteArrayOutputStream();
 		ruler.writeOut(out);
 
 		byte[] result = out.toByteArray();
@@ -72,7 +72,7 @@ public final class TestTextRulerAtom {
 	void testRead2() throws Exception {
 		TextRulerAtom ruler = TextRulerAtom.getParagraphInstance();
 		ruler.setParagraphIndent((short)249, (short)321);
-		ByteArrayOutputStream out = new ByteArrayOutputStream();
+		UnsynchronizedByteArrayOutputStream out = new UnsynchronizedByteArrayOutputStream();
 		ruler.writeOut(out);
 
 		byte[] result = out.toByteArray();
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestTextSpecInfoAtom.java b/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestTextSpecInfoAtom.java
index 77ded7d795..93e8b5e420 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestTextSpecInfoAtom.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestTextSpecInfoAtom.java
@@ -20,8 +20,7 @@ package org.apache.poi.hslf.record;
 import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
-import java.io.ByteArrayOutputStream;
-
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.junit.jupiter.api.Test;
 
 /**
@@ -54,7 +53,7 @@ public final class TestTextSpecInfoAtom  {
     @Test
     void testWrite() throws Exception {
         TextSpecInfoAtom spec = new TextSpecInfoAtom(data_1, 0, data_1.length);
-        ByteArrayOutputStream out = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream out = new UnsynchronizedByteArrayOutputStream();
         spec.writeOut(out);
         assertArrayEquals(data_1, out.toByteArray());
 	}
@@ -70,7 +69,7 @@ public final class TestTextSpecInfoAtom  {
         assertEquals(32, run[0].getLength());
 
         //serialize and read again
-        ByteArrayOutputStream out = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream out = new UnsynchronizedByteArrayOutputStream();
         spec.writeOut(out);
 
         byte[] result = out.toByteArray();
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestTxInteractiveInfoAtom.java b/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestTxInteractiveInfoAtom.java
index 12874ec041..601baf0dc6 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestTxInteractiveInfoAtom.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestTxInteractiveInfoAtom.java
@@ -21,8 +21,7 @@ package org.apache.poi.hslf.record;
 import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
-import java.io.ByteArrayOutputStream;
-
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.junit.jupiter.api.Test;
 
 /**
@@ -58,7 +57,7 @@ public final class TestTxInteractiveInfoAtom {
 	@Test
 	void testWrite() throws Exception {
 		TxInteractiveInfoAtom atom = new TxInteractiveInfoAtom(data_a, 0, data_a.length);
-		ByteArrayOutputStream baos = new ByteArrayOutputStream();
+		UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
 		atom.writeOut(baos);
 		assertArrayEquals(data_a, baos.toByteArray());
 	}
@@ -73,7 +72,7 @@ public final class TestTxInteractiveInfoAtom {
 		ia.setEndIndex(56);
 
 		// Check it's now the same as a
-		ByteArrayOutputStream baos = new ByteArrayOutputStream();
+		UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
 		ia.writeOut(baos);
 		assertArrayEquals(data_a, baos.toByteArray());
 	}
@@ -88,7 +87,7 @@ public final class TestTxInteractiveInfoAtom {
 		ia.setEndIndex(78);
 
 		// Check bytes are now the same
-		ByteArrayOutputStream baos = new ByteArrayOutputStream();
+		UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
 		ia.writeOut(baos);
 		assertArrayEquals(data_b, baos.toByteArray());
 	}
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestUserEditAtom.java b/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestUserEditAtom.java
index c09e1e55b3..42b34157d9 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestUserEditAtom.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hslf/record/TestUserEditAtom.java
@@ -21,8 +21,7 @@ package org.apache.poi.hslf.record;
 import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
-import java.io.ByteArrayOutputStream;
-
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.junit.jupiter.api.Test;
 
 /**
@@ -57,7 +56,7 @@ public final class TestUserEditAtom {
 	@Test
 	void testWrite() throws Exception {
 		UserEditAtom uea = new UserEditAtom(data_a, 0, data_a.length);
-		ByteArrayOutputStream baos = new ByteArrayOutputStream();
+		UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
 		uea.writeOut(baos);
 		assertArrayEquals(data_a, baos.toByteArray());
 	}
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hslf/usermodel/TestHSLFSlideShow.java b/poi-scratchpad/src/test/java/org/apache/poi/hslf/usermodel/TestHSLFSlideShow.java
index e1f453327d..343c1117d9 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hslf/usermodel/TestHSLFSlideShow.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hslf/usermodel/TestHSLFSlideShow.java
@@ -18,10 +18,10 @@ package org.apache.poi.hslf.usermodel;
 
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
+import java.io.InputStream;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.sl.usermodel.BaseTestSlideShow;
 import org.apache.poi.sl.usermodel.SlideShow;
 import org.junit.jupiter.api.Test;
@@ -38,15 +38,13 @@ public class TestHSLFSlideShow extends BaseTestSlideShow<HSLFShape, HSLFTextPara
         assertNotNull(createSlideShow());
     }
 
+    @Override
     public HSLFSlideShow reopen(SlideShow<HSLFShape, HSLFTextParagraph> show) throws IOException {
-        BufAccessBAOS bos = new BufAccessBAOS();
-        show.write(bos);
-        return new HSLFSlideShow(new ByteArrayInputStream(bos.getBuf()));
-    }
-
-    private static class BufAccessBAOS extends ByteArrayOutputStream {
-        byte[] getBuf() {
-            return buf;
+        try (UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream()) {
+            show.write(bos);
+            try (InputStream is = bos.toInputStream()) {
+                return new HSLFSlideShow(is);
+            }
         }
     }
 }
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hslf/usermodel/TestPictures.java b/poi-scratchpad/src/test/java/org/apache/poi/hslf/usermodel/TestPictures.java
index 5e50aa9c1f..65a2716711 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hslf/usermodel/TestPictures.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hslf/usermodel/TestPictures.java
@@ -17,13 +17,18 @@
 
 package org.apache.poi.hslf.usermodel;
 
+import static org.apache.commons.io.output.NullOutputStream.NULL_OUTPUT_STREAM;
+import static org.apache.poi.hslf.HSLFTestDataSamples.getSlideShow;
+import static org.apache.poi.hslf.HSLFTestDataSamples.writeOutAndReadBack;
 import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.junit.jupiter.api.Assertions.fail;
 
 import java.awt.Dimension;
+import java.awt.geom.Dimension2D;
+import java.awt.image.BufferedImage;
 import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.net.URL;
 import java.util.Arrays;
@@ -31,12 +36,13 @@ import java.util.Collections;
 import java.util.List;
 import java.util.Random;
 
+import javax.imageio.ImageIO;
+
+import org.apache.commons.io.output.CountingOutputStream;
 import org.apache.poi.POIDataSamples;
 import org.apache.poi.ddf.EscherBSERecord;
 import org.apache.poi.ddf.EscherContainerRecord;
 import org.apache.poi.ddf.EscherRecord;
-import org.apache.poi.hslf.HSLFTestDataSamples;
-import org.apache.poi.hslf.blip.DIB;
 import org.apache.poi.hslf.blip.EMF;
 import org.apache.poi.hslf.blip.JPEG;
 import org.apache.poi.hslf.blip.PICT;
@@ -50,6 +56,8 @@ import org.apache.poi.sl.usermodel.PictureData.PictureType;
 import org.apache.poi.util.Units;
 import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
 
 /**
  * Test adding/reading pictures
@@ -58,302 +66,101 @@ public final class TestPictures {
     private static final POIDataSamples slTests = POIDataSamples.getSlideShowInstance();
 
     /**
-     * Test read/write Macintosh PICT
-     */
-    @Test
-    void testPICT() throws IOException {
-        HSLFSlideShow ppt = new HSLFSlideShow();
-
-        HSLFSlide slide = ppt.createSlide();
-        byte[] src_bytes = slTests.readFile("cow.pict");
-        HSLFPictureData data = ppt.addPicture(src_bytes, PictureType.PICT);
-        ImageHeaderPICT nHeader = new ImageHeaderPICT(src_bytes, 512);
-        final int expWidth = 197, expHeight = 137;
-        Dimension nDim = nHeader.getSize();
-        assertEquals(expWidth, nDim.getWidth(), 0);
-        assertEquals(expHeight, nDim.getHeight(), 0);
-
-        Dimension dim = data.getImageDimensionInPixels();
-        assertEquals(Units.pointsToPixel(expWidth), dim.getWidth(), 0);
-        assertEquals(Units.pointsToPixel(expHeight), dim.getHeight(), 0);
-
-        HSLFPictureShape pict = new HSLFPictureShape(data);
-        assertEquals(data.getIndex(), pict.getPictureIndex());
-        slide.addShape(pict);
-
-        //serialize and read again
-        ByteArrayOutputStream out = new ByteArrayOutputStream();
-        ppt.write(out);
-        out.close();
-
-        ppt = new HSLFSlideShow(new HSLFSlideShowImpl(new ByteArrayInputStream(out.toByteArray())));
-
-        //make sure we can read this picture shape and it refers to the correct picture data
-        List<HSLFShape> sh = ppt.getSlides().get(0).getShapes();
-        assertEquals(1, sh.size());
-        pict = (HSLFPictureShape)sh.get(0);
-        assertEquals(data.getIndex(), pict.getPictureIndex());
-
-        //check picture data
-        List<HSLFPictureData> pictures = ppt.getPictureData();
-        assertEquals(1, pictures.size());
-
-        HSLFPictureData pd = pictures.get(0);
-        dim = pd.getImageDimension();
-        assertEquals(expWidth, dim.width);
-        assertEquals(expHeight, dim.height);
-
-        //the Picture shape refers to the PictureData object in the Presentation
-        assertEquals(pict.getPictureData(), pd);
-
-        assertEquals(1, pictures.size());
-        assertEquals(PictureType.PICT, pd.getType());
-        assertTrue(pd instanceof PICT);
-        //compare the content of the initial file with what is stored in the PictureData
-        byte[] ppt_bytes = pd.getData();
-        assertEquals(src_bytes.length, ppt_bytes.length);
-        //in PICT the first 512 bytes are MAC specific and may not be preserved, ignore them
-        byte[] b1 = Arrays.copyOfRange(src_bytes, 512, src_bytes.length);
-        byte[] b2 = Arrays.copyOfRange(ppt_bytes, 512, ppt_bytes.length);
-        assertArrayEquals(b1, b2);
-    }
-
-    /**
-     * Test read/write WMF
-     */
-    @Test
-    void testWMF() throws IOException {
-        HSLFSlideShow ppt = new HSLFSlideShow();
-
-        HSLFSlide slide = ppt.createSlide();
-        byte[] src_bytes = slTests.readFile("santa.wmf");
-        HSLFPictureData data = ppt.addPicture(src_bytes, PictureType.WMF);
-        ImageHeaderWMF nHeader = new ImageHeaderWMF(src_bytes, 0);
-        final int expWidth = 136, expHeight = 146;
-        Dimension nDim = nHeader.getSize();
-        assertEquals(expWidth, nDim.getWidth(), 0);
-        assertEquals(expHeight, nDim.getHeight(), 0);
-
-        Dimension dim = data.getImageDimensionInPixels();
-        assertEquals(Units.pointsToPixel(expWidth), dim.getWidth(), 0);
-        assertEquals(Units.pointsToPixel(expHeight), dim.getHeight(), 0);
-
-        HSLFPictureShape pict = new HSLFPictureShape(data);
-        assertEquals(data.getIndex(), pict.getPictureIndex());
-        slide.addShape(pict);
-
-        //serialize and read again
-        ByteArrayOutputStream out = new ByteArrayOutputStream();
-        ppt.write(out);
-        out.close();
-
-        ppt = new HSLFSlideShow(new HSLFSlideShowImpl(new ByteArrayInputStream(out.toByteArray())));
-
-        //make sure we can read this picture shape and it refers to the correct picture data
-        List<HSLFShape> sh = ppt.getSlides().get(0).getShapes();
-        assertEquals(1, sh.size());
-        pict = (HSLFPictureShape)sh.get(0);
-        assertEquals(data.getIndex(), pict.getPictureIndex());
-
-        //check picture data
-        List<HSLFPictureData> pictures = ppt.getPictureData();
-        assertEquals(1, pictures.size());
-
-        HSLFPictureData pd = pictures.get(0);
-        dim = pd.getImageDimension();
-        assertEquals(expWidth, dim.width);
-        assertEquals(expHeight, dim.height);
-
-        //the Picture shape refers to the PictureData object in the Presentation
-        assertEquals(pict.getPictureData(), pd);
-
-        assertEquals(PictureType.WMF, pd.getType());
-        assertTrue(pd instanceof WMF);
-        //compare the content of the initial file with what is stored in the PictureData
-        byte[] ppt_bytes = pd.getData();
-        assertEquals(src_bytes.length, ppt_bytes.length);
-        //in WMF the first 22 bytes - is a metafile header
-        byte[] b1 = Arrays.copyOfRange(src_bytes, 22, src_bytes.length);
-        byte[] b2 = Arrays.copyOfRange(ppt_bytes, 22, ppt_bytes.length);
-        assertArrayEquals(b1, b2);
-    }
-
-    /**
-     * Test read/write EMF
+     * Test add/read/write images
      */
-    @Test
-    void testEMF() throws IOException {
-        HSLFSlideShow ppt = new HSLFSlideShow();
-
-        HSLFSlide slide = ppt.createSlide();
-        byte[] src_bytes = slTests.readFile("wrench.emf");
-        HSLFPictureData data = ppt.addPicture(src_bytes, PictureType.EMF);
-        ImageHeaderEMF nHeader = new ImageHeaderEMF(src_bytes, 0);
-        final int expWidth = 190, expHeight = 115;
-        Dimension nDim = nHeader.getSize();
-        assertEquals(expWidth, nDim.getWidth(), 0);
-        assertEquals(expHeight, nDim.getHeight(), 0);
-
-        Dimension dim = data.getImageDimensionInPixels();
-        assertEquals(Units.pointsToPixel(expWidth), dim.getWidth(), 0);
-        assertEquals(Units.pointsToPixel(expHeight), dim.getHeight(), 0);
-
-        HSLFPictureShape pict = new HSLFPictureShape(data);
-        assertEquals(data.getIndex(), pict.getPictureIndex());
-        slide.addShape(pict);
-
-        //serialize and read again
-        ByteArrayOutputStream out = new ByteArrayOutputStream();
-        ppt.write(out);
-        out.close();
-
-        ppt = new HSLFSlideShow(new HSLFSlideShowImpl(new ByteArrayInputStream(out.toByteArray())));
-
-        //make sure we can get this picture shape and it refers to the correct picture data
-        List<HSLFShape> sh = ppt.getSlides().get(0).getShapes();
-        assertEquals(1, sh.size());
-        pict = (HSLFPictureShape)sh.get(0);
-        assertEquals(data.getIndex(), pict.getPictureIndex());
-
-        //check picture data
-        List<HSLFPictureData> pictures = ppt.getPictureData();
-        assertEquals(1, pictures.size());
-
-        HSLFPictureData pd = pictures.get(0);
-        dim = pd.getImageDimension();
-        assertEquals(expWidth, dim.width);
-        assertEquals(expHeight, dim.height);
-
-        //the Picture shape refers to the PictureData object in the Presentation
-        assertEquals(pict.getPictureData(), pd);
-
-        assertEquals(1, pictures.size());
-        assertEquals(PictureType.EMF, pd.getType());
-        assertTrue(pd instanceof EMF);
-        //compare the content of the initial file with what is stored in the PictureData
-        byte[] ppt_bytes = pd.getData();
-        assertArrayEquals(src_bytes, ppt_bytes);
-    }
-
-    /**
-     * Test read/write PNG
-     */
-    @Test
-    void testPNG() throws IOException {
-        HSLFSlideShow ppt = new HSLFSlideShow();
-
-        HSLFSlide slide = ppt.createSlide();
-        byte[] src_bytes = slTests.readFile("tomcat.png");
-        HSLFPictureData data = ppt.addPicture(src_bytes, PictureType.PNG);
-        HSLFPictureShape pict = new HSLFPictureShape(data);
-        assertEquals(data.getIndex(), pict.getPictureIndex());
-        slide.addShape(pict);
-
-        //serialize and read again
-        ByteArrayOutputStream out = new ByteArrayOutputStream();
-        ppt.write(out);
-        out.close();
-
-        ppt = new HSLFSlideShow(new HSLFSlideShowImpl(new ByteArrayInputStream(out.toByteArray())));
-
-        //make sure we can read this picture shape and it refers to the correct picture data
-        List<HSLFShape> sh = ppt.getSlides().get(0).getShapes();
-        assertEquals(1, sh.size());
-        pict = (HSLFPictureShape)sh.get(0);
-        assertEquals(data.getIndex(), pict.getPictureIndex());
-
-        //check picture data
-        List<HSLFPictureData> pictures = ppt.getPictureData();
-        //the Picture shape refers to the PictureData object in the Presentation
-        assertEquals(pict.getPictureData(), pictures.get(0));
-
-        assertEquals(1, pictures.size());
-        assertEquals(PictureType.PNG, pictures.get(0).getType());
-        assertTrue(pictures.get(0) instanceof PNG);
-        //compare the content of the initial file with what is stored in the PictureData
-        byte[] ppt_bytes = pictures.get(0).getData();
-        assertArrayEquals(src_bytes, ppt_bytes);
-    }
-
-    /**
-     * Test read/write JPEG
-     */
-    @Test
-    void testJPEG() throws IOException {
-        HSLFSlideShow ppt = new HSLFSlideShow();
-
-        HSLFSlide slide = ppt.createSlide();
-        byte[] src_bytes = slTests.readFile("clock.jpg");
-        HSLFPictureData data = ppt.addPicture(src_bytes, PictureType.JPEG);
-
-        HSLFPictureShape pict = new HSLFPictureShape(data);
-        assertEquals(data.getIndex(), pict.getPictureIndex());
-        slide.addShape(pict);
-
-        //serialize and read again
-        ByteArrayOutputStream out = new ByteArrayOutputStream();
-        ppt.write(out);
-        out.close();
-
-        ppt = new HSLFSlideShow(new HSLFSlideShowImpl(new ByteArrayInputStream(out.toByteArray())));
-
-        //make sure we can read this picture shape and it refers to the correct picture data
-        List<HSLFShape> sh = ppt.getSlides().get(0).getShapes();
-        assertEquals(1, sh.size());
-        pict = (HSLFPictureShape)sh.get(0);
-        assertEquals(data.getIndex(), pict.getPictureIndex());
-
-        //check picture data
-        List<HSLFPictureData> pictures = ppt.getPictureData();
-        //the Picture shape refers to the PictureData object in the Presentation
-        assertEquals(pict.getPictureData(), pictures.get(0));
-
-        assertEquals(1, pictures.size());
-        assertEquals(PictureType.JPEG, pictures.get(0).getType());
-        assertTrue(pictures.get(0) instanceof JPEG);
-        //compare the content of the initial file with what is stored in the PictureData
-        byte[] ppt_bytes = pictures.get(0).getData();
-        assertArrayEquals(src_bytes, ppt_bytes);
-    }
-
-    /**
-     * Test read/write DIB
-     */
-    @Test
-    void testDIB() throws IOException {
-        HSLFSlideShow ppt = new HSLFSlideShow();
-
-        HSLFSlide slide = ppt.createSlide();
-        byte[] src_bytes = slTests.readFile("clock.dib");
-        HSLFPictureData data = ppt.addPicture(src_bytes, PictureType.DIB);
-        HSLFPictureShape pict = new HSLFPictureShape(data);
-        assertEquals(data.getIndex(), pict.getPictureIndex());
-        slide.addShape(pict);
-
-        //serialize and read again
-        ByteArrayOutputStream out = new ByteArrayOutputStream();
-        ppt.write(out);
-        out.close();
-
-        ppt = new HSLFSlideShow(new HSLFSlideShowImpl(new ByteArrayInputStream(out.toByteArray())));
-
-        //make sure we can read this picture shape and it refers to the correct picture data
-        List<HSLFShape> sh = ppt.getSlides().get(0).getShapes();
-        assertEquals(1, sh.size());
-        pict = (HSLFPictureShape)sh.get(0);
-        assertEquals(data.getIndex(), pict.getPictureIndex());
-
-        //check picture data
-        List<HSLFPictureData> pictures = ppt.getPictureData();
-        //the Picture shape refers to the PictureData object in the Presentation
-        assertEquals(pict.getPictureData(), pictures.get(0));
-
-        assertEquals(1, pictures.size());
-        assertEquals(PictureType.DIB, pictures.get(0).getType());
-        assertTrue(pictures.get(0) instanceof DIB);
-        //compare the content of the initial file with what is stored in the PictureData
-        byte[] ppt_bytes = pictures.get(0).getData();
-        assertArrayEquals(src_bytes, ppt_bytes);
+    @ParameterizedTest()
+    @CsvSource(value = {
+        // in PICT the first 512 bytes are MAC specific and may not be preserved, ignore them
+        "PICT, cow.pict, 197, 137, 512, org.apache.poi.hslf.blip.PICT",
+        // in WMF the first 22 bytes - is a metafile header
+        "WMF, santa.wmf, 136, 146, 22, org.apache.poi.hslf.blip.WMF",
+        "EMF, wrench.emf, 190, 115, 0, org.apache.poi.hslf.blip.EMF",
+        "PNG, tomcat.png, 129, 92, 0, org.apache.poi.hslf.blip.PNG",
+        "JPEG, clock.jpg, 192, 176, 0, org.apache.poi.hslf.blip.JPEG",
+        "DIB, clock.dib, 192, 176, 0, org.apache.poi.hslf.blip.DIB"
+    })
+    void testAddPictures(PictureType pictureType, String imgFile, int expWidth, int expHeight, int headerOffset, Class<?> imgClazz) throws IOException {
+        byte[] src_bytes = slTests.readFile(imgFile);
+
+        int dataIndex;
+        try (HSLFSlideShow ppt1 = new HSLFSlideShow()) {
+
+            HSLFSlide slide1 = ppt1.createSlide();
+            HSLFPictureData data1 = ppt1.addPicture(src_bytes, pictureType);
+            dataIndex = data1.getIndex();
+
+            // TODO: Fix the differences in the frame sizes
+            Dimension2D dimN, dimFrame1, dimFrame2;
+            switch (pictureType) {
+                case PICT:
+                    dimN = new ImageHeaderPICT(src_bytes, headerOffset).getSize();
+                    dimFrame1 = Units.pointsToPixel(dimN);
+                    dimFrame2 = dimN;
+                    break;
+                case WMF:
+                    dimN = new ImageHeaderWMF(src_bytes, 0).getSize();
+                    dimFrame1 = Units.pointsToPixel(dimN);
+                    dimFrame2 = dimN;
+                    break;
+                case EMF:
+                    dimN = new ImageHeaderEMF(src_bytes, 0).getSize();
+                    dimFrame1 = Units.pointsToPixel(dimN);
+                    dimFrame2 = dimN;
+                    break;
+                case JPEG:
+                case DIB:
+                case PNG: {
+                    BufferedImage png = ImageIO.read(new ByteArrayInputStream(src_bytes));
+                    dimN = new Dimension(png.getWidth(), png.getHeight());
+                    dimFrame1 = dimN;
+                    dimFrame2 = Units.pixelToPoints(dimN);
+                    break;
+                }
+                default:
+                    fail();
+                    return;
+            }
+            assertEquals(expWidth, dimN.getWidth(), 1);
+            assertEquals(expHeight, dimN.getHeight(), 1);
+
+            Dimension dim1 = data1.getImageDimensionInPixels();
+            assertEquals(dimFrame1.getWidth(), dim1.getWidth(), 1);
+            assertEquals(dimFrame1.getHeight(), dim1.getHeight(), 1);
+
+            HSLFPictureShape pict1 = new HSLFPictureShape(data1);
+            assertEquals(data1.getIndex(), pict1.getPictureIndex());
+            slide1.addShape(pict1);
+
+            try (HSLFSlideShow ppt2 = writeOutAndReadBack(ppt1)) {
+                //make sure we can read this picture shape and it refers to the correct picture data
+                List<HSLFShape> sh2 = ppt2.getSlides().get(0).getShapes();
+                assertEquals(1, sh2.size());
+                HSLFPictureShape pict2 = (HSLFPictureShape) sh2.get(0);
+                assertEquals(dataIndex, pict2.getPictureIndex());
+
+                //check picture data
+                List<HSLFPictureData> pictures2 = ppt2.getPictureData();
+                assertEquals(1, pictures2.size());
+
+                HSLFPictureData pd2 = pictures2.get(0);
+                Dimension dim2 = pd2.getImageDimension();
+                assertEquals(dimFrame2.getWidth(), dim2.width, 1);
+                assertEquals(dimFrame2.getHeight(), dim2.height, 1);
+
+                //the Picture shape refers to the PictureData object in the Presentation
+                assertEquals(pict2.getPictureData(), pd2);
+
+                assertEquals(1, pictures2.size());
+                assertEquals(pictureType, pd2.getType());
+                assertTrue(imgClazz.isInstance(pd2));
+                //compare the content of the initial file with what is stored in the PictureData
+                byte[] ppt_bytes = pd2.getData();
+                assertEquals(src_bytes.length, ppt_bytes.length);
+                byte[] b1 = Arrays.copyOfRange(src_bytes, headerOffset, src_bytes.length);
+                byte[] b2 = Arrays.copyOfRange(ppt_bytes, headerOffset, ppt_bytes.length);
+                assertArrayEquals(b1, b2);
+            }
+        }
     }
 
     /**
@@ -366,60 +173,59 @@ public final class TestPictures {
         HSLFPictureShape pict;
         HSLFPictureData pdata;
 
-        HSLFSlideShow ppt = HSLFTestDataSamples.getSlideShow("pictures.ppt");
-        List<HSLFSlide> slides = ppt.getSlides();
-        List<HSLFPictureData> pictures = ppt.getPictureData();
-        assertEquals(5, pictures.size());
-
-        pict = (HSLFPictureShape)slides.get(0).getShapes().get(0); //the first slide contains JPEG
-        pdata = pict.getPictureData();
-        assertTrue(pdata instanceof JPEG);
-        assertEquals(PictureType.JPEG, pdata.getType());
-        src_bytes = pdata.getData();
-        ppt_bytes = slTests.readFile("clock.jpg");
-        assertArrayEquals(src_bytes, ppt_bytes);
-
-        pict = (HSLFPictureShape)slides.get(1).getShapes().get(0); //the second slide contains PNG
-        pdata = pict.getPictureData();
-        assertTrue(pdata instanceof PNG);
-        assertEquals(PictureType.PNG, pdata.getType());
-        src_bytes = pdata.getData();
-        ppt_bytes = slTests.readFile("tomcat.png");
-        assertArrayEquals(src_bytes, ppt_bytes);
-
-        pict = (HSLFPictureShape)slides.get(2).getShapes().get(0); //the third slide contains WMF
-        pdata = pict.getPictureData();
-        assertTrue(pdata instanceof WMF);
-        assertEquals(PictureType.WMF, pdata.getType());
-        src_bytes = pdata.getData();
-        ppt_bytes = slTests.readFile("santa.wmf");
-        assertEquals(src_bytes.length, ppt_bytes.length);
-        //ignore the first 22 bytes - it is a WMF metafile header
-        b1 = Arrays.copyOfRange(src_bytes, 22, src_bytes.length);
-        b2 = Arrays.copyOfRange(ppt_bytes, 22, ppt_bytes.length);
-        assertArrayEquals(b1, b2);
-
-        pict = (HSLFPictureShape)slides.get(3).getShapes().get(0); //the forth slide contains PICT
-        pdata = pict.getPictureData();
-        assertTrue(pdata instanceof PICT);
-        assertEquals(PictureType.PICT, pdata.getType());
-        src_bytes = pdata.getData();
-        ppt_bytes = slTests.readFile("cow.pict");
-        assertEquals(src_bytes.length, ppt_bytes.length);
-        //ignore the first 512 bytes - it is a MAC specific crap
-        b1 = Arrays.copyOfRange(src_bytes, 512, src_bytes.length);
-        b2 = Arrays.copyOfRange(ppt_bytes, 512, ppt_bytes.length);
-        assertArrayEquals(b1, b2);
-
-        pict = (HSLFPictureShape)slides.get(4).getShapes().get(0); //the fifth slide contains EMF
-        pdata = pict.getPictureData();
-        assertTrue(pdata instanceof EMF);
-        assertEquals(PictureType.EMF, pdata.getType());
-        src_bytes = pdata.getData();
-        ppt_bytes = slTests.readFile("wrench.emf");
-        assertArrayEquals(src_bytes, ppt_bytes);
-
-        ppt.close();
+        try (HSLFSlideShow ppt = getSlideShow("pictures.ppt")) {
+            List<HSLFSlide> slides = ppt.getSlides();
+            List<HSLFPictureData> pictures = ppt.getPictureData();
+            assertEquals(5, pictures.size());
+
+            pict = (HSLFPictureShape) slides.get(0).getShapes().get(0); //the first slide contains JPEG
+            pdata = pict.getPictureData();
+            assertTrue(pdata instanceof JPEG);
+            assertEquals(PictureType.JPEG, pdata.getType());
+            src_bytes = pdata.getData();
+            ppt_bytes = slTests.readFile("clock.jpg");
+            assertArrayEquals(src_bytes, ppt_bytes);
+
+            pict = (HSLFPictureShape) slides.get(1).getShapes().get(0); //the second slide contains PNG
+            pdata = pict.getPictureData();
+            assertTrue(pdata instanceof PNG);
+            assertEquals(PictureType.PNG, pdata.getType());
+            src_bytes = pdata.getData();
+            ppt_bytes = slTests.readFile("tomcat.png");
+            assertArrayEquals(src_bytes, ppt_bytes);
+
+            pict = (HSLFPictureShape) slides.get(2).getShapes().get(0); //the third slide contains WMF
+            pdata = pict.getPictureData();
+            assertTrue(pdata instanceof WMF);
+            assertEquals(PictureType.WMF, pdata.getType());
+            src_bytes = pdata.getData();
+            ppt_bytes = slTests.readFile("santa.wmf");
+            assertEquals(src_bytes.length, ppt_bytes.length);
+            //ignore the first 22 bytes - it is a WMF metafile header
+            b1 = Arrays.copyOfRange(src_bytes, 22, src_bytes.length);
+            b2 = Arrays.copyOfRange(ppt_bytes, 22, ppt_bytes.length);
+            assertArrayEquals(b1, b2);
+
+            pict = (HSLFPictureShape) slides.get(3).getShapes().get(0); //the forth slide contains PICT
+            pdata = pict.getPictureData();
+            assertTrue(pdata instanceof PICT);
+            assertEquals(PictureType.PICT, pdata.getType());
+            src_bytes = pdata.getData();
+            ppt_bytes = slTests.readFile("cow.pict");
+            assertEquals(src_bytes.length, ppt_bytes.length);
+            //ignore the first 512 bytes - it is a MAC specific crap
+            b1 = Arrays.copyOfRange(src_bytes, 512, src_bytes.length);
+            b2 = Arrays.copyOfRange(ppt_bytes, 512, ppt_bytes.length);
+            assertArrayEquals(b1, b2);
+
+            pict = (HSLFPictureShape) slides.get(4).getShapes().get(0); //the fifth slide contains EMF
+            pdata = pict.getPictureData();
+            assertTrue(pdata instanceof EMF);
+            assertEquals(PictureType.EMF, pdata.getType());
+            src_bytes = pdata.getData();
+            ppt_bytes = slTests.readFile("wrench.emf");
+            assertArrayEquals(src_bytes, ppt_bytes);
+        }
     }
 
 	/**
@@ -428,35 +234,34 @@ public final class TestPictures {
 	 */
     @Test
 	void testZeroPictureType() throws IOException {
-		HSLFSlideShowImpl hslf = new HSLFSlideShowImpl(slTests.openResourceAsStream("PictureTypeZero.ppt"));
-
-		// Should still have 2 real pictures
-		assertEquals(2, hslf.getPictureData().size());
-		// Both are real pictures, both WMF
-		assertEquals(PictureType.WMF, hslf.getPictureData().get(0).getType());
-		assertEquals(PictureType.WMF, hslf.getPictureData().get(1).getType());
-
-		// Now test what happens when we use the SlideShow interface
-		HSLFSlideShow ppt = new HSLFSlideShow(hslf);
-        List<HSLFSlide> slides = ppt.getSlides();
-        List<HSLFPictureData> pictures = ppt.getPictureData();
-        assertEquals(12, slides.size());
-        assertEquals(2, pictures.size());
-
-		HSLFPictureShape pict;
-		HSLFPictureData pdata;
-
-        pict = (HSLFPictureShape)slides.get(0).getShapes().get(1); // 2nd object on 1st slide
-        pdata = pict.getPictureData();
-        assertTrue(pdata instanceof WMF);
-        assertEquals(PictureType.WMF, pdata.getType());
-
-        pict = (HSLFPictureShape)slides.get(0).getShapes().get(2); // 3rd object on 1st slide
-        pdata = pict.getPictureData();
-        assertTrue(pdata instanceof WMF);
-        assertEquals(PictureType.WMF, pdata.getType());
-
-        ppt.close();
+		try (HSLFSlideShowImpl hslf = new HSLFSlideShowImpl(slTests.openResourceAsStream("PictureTypeZero.ppt"))) {
+
+            // Should still have 2 real pictures
+            assertEquals(2, hslf.getPictureData().size());
+            // Both are real pictures, both WMF
+            assertEquals(PictureType.WMF, hslf.getPictureData().get(0).getType());
+            assertEquals(PictureType.WMF, hslf.getPictureData().get(1).getType());
+
+            // Now test what happens when we use the SlideShow interface
+            HSLFSlideShow ppt = new HSLFSlideShow(hslf);
+            List<HSLFSlide> slides = ppt.getSlides();
+            List<HSLFPictureData> pictures = ppt.getPictureData();
+            assertEquals(12, slides.size());
+            assertEquals(2, pictures.size());
+
+            HSLFPictureShape pict;
+            HSLFPictureData pdata;
+
+            pict = (HSLFPictureShape) slides.get(0).getShapes().get(1); // 2nd object on 1st slide
+            pdata = pict.getPictureData();
+            assertTrue(pdata instanceof WMF);
+            assertEquals(PictureType.WMF, pdata.getType());
+
+            pict = (HSLFPictureShape) slides.get(0).getShapes().get(2); // 3rd object on 1st slide
+            pdata = pict.getPictureData();
+            assertTrue(pdata instanceof WMF);
+            assertEquals(PictureType.WMF, pdata.getType());
+        }
 	}
 
     /**
@@ -490,75 +295,70 @@ public final class TestPictures {
 		assertEquals(PictureType.WMF, hslf.getPictureData().get(1).getType());
 
 		// Now test what happens when we use the SlideShow interface
-		HSLFSlideShow ppt = new HSLFSlideShow(hslf);
-        List<HSLFSlide> slides = ppt.getSlides();
-        List<HSLFPictureData> pictures = ppt.getPictureData();
-        assertEquals(27, slides.size());
-        assertEquals(2, pictures.size());
-
-		HSLFPictureShape pict;
-		HSLFPictureData pdata;
-
-        pict = (HSLFPictureShape)slides.get(6).getShapes().get(13);
-        pdata = pict.getPictureData();
-        assertTrue(pdata instanceof WMF);
-        assertEquals(PictureType.WMF, pdata.getType());
-
-        pict = (HSLFPictureShape)slides.get(7).getShapes().get(13);
-        pdata = pict.getPictureData();
-        assertTrue(pdata instanceof WMF);
-        assertEquals(PictureType.WMF, pdata.getType());
-
-        //add a new picture, it should be correctly appended to the Pictures stream
-        ByteArrayOutputStream out = new ByteArrayOutputStream();
-        for(HSLFPictureData p : pictures) p.write(out);
-        out.close();
-
-        int streamSize = out.size();
-
-        HSLFPictureData data = ppt.addPicture(new byte[100], PictureType.JPEG);
-        int offset = data.getOffset();
-        assertEquals(streamSize, offset);
-        assertEquals(3, ppt.getPictureData().size());
-
-        ppt.close();
+		try (HSLFSlideShow ppt = new HSLFSlideShow(hslf)) {
+            List<HSLFSlide> slides = ppt.getSlides();
+            List<HSLFPictureData> pictures = ppt.getPictureData();
+            assertEquals(27, slides.size());
+            assertEquals(2, pictures.size());
+
+            HSLFPictureShape pict;
+            HSLFPictureData pdata;
+
+            pict = (HSLFPictureShape) slides.get(6).getShapes().get(13);
+            pdata = pict.getPictureData();
+            assertTrue(pdata instanceof WMF);
+            assertEquals(PictureType.WMF, pdata.getType());
+
+            pict = (HSLFPictureShape) slides.get(7).getShapes().get(13);
+            pdata = pict.getPictureData();
+            assertTrue(pdata instanceof WMF);
+            assertEquals(PictureType.WMF, pdata.getType());
+
+            //add a new picture, it should be correctly appended to the Pictures stream
+            CountingOutputStream out = new CountingOutputStream(NULL_OUTPUT_STREAM);
+            for (HSLFPictureData p : pictures) p.write(out);
+
+            int streamSize = out.getCount();
+
+            HSLFPictureData data = ppt.addPicture(new byte[100], PictureType.JPEG);
+            int offset = data.getOffset();
+            assertEquals(streamSize, offset);
+            assertEquals(3, ppt.getPictureData().size());
+        }
     }
 
     @Test
     void testGetPictureName() throws IOException {
-        HSLFSlideShow ppt = HSLFTestDataSamples.getSlideShow("ppt_with_png.ppt");
-        HSLFSlide slide = ppt.getSlides().get(0);
+        try (HSLFSlideShow ppt = getSlideShow("ppt_with_png.ppt")) {
+            HSLFSlide slide = ppt.getSlides().get(0);
 
-        HSLFPictureShape p = (HSLFPictureShape)slide.getShapes().get(0); //the first slide contains JPEG
-        assertEquals("test", p.getPictureName());
-        ppt.close();
+            HSLFPictureShape p = (HSLFPictureShape) slide.getShapes().get(0); //the first slide contains JPEG
+            assertEquals("test", p.getPictureName());
+        }
     }
 
     @Test
     void testSetPictureName() throws IOException {
-        HSLFSlideShow ppt = new HSLFSlideShow();
-
-        HSLFSlide slide = ppt.createSlide();
-        byte[] img = slTests.readFile("tomcat.png");
-        HSLFPictureData data = ppt.addPicture(img, PictureType.PNG);
-        HSLFPictureShape pict = new HSLFPictureShape(data);
-        pict.setPictureName("tomcat.png");
-        slide.addShape(pict);
-
-        //serialize and read again
-        ByteArrayOutputStream out = new ByteArrayOutputStream();
-        ppt.write(out);
-        out.close();
-
-        ppt = new HSLFSlideShow(new ByteArrayInputStream(out.toByteArray()));
-
-        HSLFPictureShape p = (HSLFPictureShape)ppt.getSlides().get(0).getShapes().get(0);
-        assertEquals("tomcat.png", p.getPictureName());
+        try (HSLFSlideShow ppt1 = new HSLFSlideShow()) {
+
+            HSLFSlide slide = ppt1.createSlide();
+            byte[] img = slTests.readFile("tomcat.png");
+            HSLFPictureData data = ppt1.addPicture(img, PictureType.PNG);
+            HSLFPictureShape pict = new HSLFPictureShape(data);
+            pict.setPictureName("tomcat.png");
+            slide.addShape(pict);
+
+            //serialize and read again
+            try (HSLFSlideShow ppt2 = writeOutAndReadBack(ppt1)) {
+                HSLFPictureShape p = (HSLFPictureShape) ppt2.getSlides().get(0).getShapes().get(0);
+                assertEquals("tomcat.png", p.getPictureName());
+            }
+        }
     }
 
     @Test
     void testPictureIndexIsOneBased() throws IOException {
-        try (HSLFSlideShow ppt = HSLFTestDataSamples.getSlideShow("ppt_with_png.ppt")) {
+        try (HSLFSlideShow ppt = getSlideShow("ppt_with_png.ppt")) {
             HSLFPictureData picture = ppt.getPictureData().get(0);
             assertEquals(1, picture.getIndex());
         }
@@ -571,20 +371,18 @@ public final class TestPictures {
     @Test
     void testEditPictureData() throws IOException {
         byte[] newImage = slTests.readFile("tomcat.png");
-        ByteArrayOutputStream modifiedSlideShow = new ByteArrayOutputStream();
 
         // Load an existing slideshow and modify the image
-        try (HSLFSlideShow ppt = HSLFTestDataSamples.getSlideShow("ppt_with_png.ppt")) {
-            HSLFPictureData picture = ppt.getPictureData().get(0);
-            picture.setData(newImage);
-            ppt.write(modifiedSlideShow);
-        }
+        try (HSLFSlideShow ppt1 = getSlideShow("ppt_with_png.ppt")) {
+            HSLFPictureData picture1 = ppt1.getPictureData().get(0);
+            picture1.setData(newImage);
 
-        // Load the modified slideshow and verify the image content
-        try (HSLFSlideShow ppt = new HSLFSlideShow(new ByteArrayInputStream(modifiedSlideShow.toByteArray()))) {
-            HSLFPictureData picture = ppt.getPictureData().get(0);
-            byte[] modifiedImageData = picture.getData();
-            assertArrayEquals(newImage, modifiedImageData);
+            // Load the modified slideshow and verify the image content
+            try (HSLFSlideShow ppt2 = writeOutAndReadBack(ppt1)) {
+                HSLFPictureData picture2 = ppt2.getPictureData().get(0);
+                byte[] modifiedImageData = picture2.getData();
+                assertArrayEquals(newImage, modifiedImageData);
+            }
         }
     }
 
@@ -595,22 +393,20 @@ public final class TestPictures {
     @Test
     void testEditPictureDataEncrypted() throws IOException {
         byte[] newImage = slTests.readFile("tomcat.png");
-        ByteArrayOutputStream modifiedSlideShow = new ByteArrayOutputStream();
 
         Biff8EncryptionKey.setCurrentUserPassword("password");
         try {
             // Load an existing slideshow and modify the image
-            try (HSLFSlideShow ppt = HSLFTestDataSamples.getSlideShow("ppt_with_png_encrypted.ppt")) {
-                HSLFPictureData picture = ppt.getPictureData().get(0);
-                picture.setData(newImage);
-                ppt.write(modifiedSlideShow);
-            }
-
-            // Load the modified slideshow and verify the image content
-            try (HSLFSlideShow ppt = new HSLFSlideShow(new ByteArrayInputStream(modifiedSlideShow.toByteArray()))) {
-                HSLFPictureData picture = ppt.getPictureData().get(0);
-                byte[] modifiedImageData = picture.getData();
-                assertArrayEquals(newImage, modifiedImageData);
+            try (HSLFSlideShow ppt1 = getSlideShow("ppt_with_png_encrypted.ppt")) {
+                HSLFPictureData picture1 = ppt1.getPictureData().get(0);
+                picture1.setData(newImage);
+
+                // Load the modified slideshow and verify the image content
+                try (HSLFSlideShow ppt2 = writeOutAndReadBack(ppt1)) {
+                    HSLFPictureData picture2 = ppt2.getPictureData().get(0);
+                    byte[] modifiedImageData = picture2.getData();
+                    assertArrayEquals(newImage, modifiedImageData);
+                }
             }
         } finally {
             Biff8EncryptionKey.setCurrentUserPassword(null);
@@ -626,27 +422,23 @@ public final class TestPictures {
         int[] originalOffsets = {0, 12013, 15081, 34162, 59563};
         int[] modifiedOffsets = {0, 35, 3103, 22184, 47585};
 
-        ByteArrayOutputStream inMemory = new ByteArrayOutputStream();
-        try (HSLFSlideShow ppt = HSLFTestDataSamples.getSlideShow("pictures.ppt")) {
-            int[] offsets = ppt.getPictureData().stream().mapToInt(HSLFPictureData::getOffset).toArray();
-            assertArrayEquals(originalOffsets, offsets);
+        try (HSLFSlideShow ppt1 = getSlideShow("pictures.ppt")) {
+            int[] offsets1 = ppt1.getPictureData().stream().mapToInt(HSLFPictureData::getOffset).toArray();
+            assertArrayEquals(originalOffsets, offsets1);
 
-            HSLFPictureData imageBeingChanged = ppt.getPictureData().get(0);
+            HSLFPictureData imageBeingChanged = ppt1.getPictureData().get(0);
             // It doesn't matter that this isn't a valid image. We are just testing offsets here.
             imageBeingChanged.setData(new byte[10]);
 
             // Verify that the in-memory representations have all been updated
-            offsets = ppt.getPictureData().stream().mapToInt(HSLFPictureData::getOffset).toArray();
-            assertArrayEquals(modifiedOffsets, offsets);
-
-            ppt.write(inMemory);
-        }
-
-        try (HSLFSlideShow ppt = new HSLFSlideShow(new ByteArrayInputStream(inMemory.toByteArray()))) {
+            offsets1 = ppt1.getPictureData().stream().mapToInt(HSLFPictureData::getOffset).toArray();
+            assertArrayEquals(modifiedOffsets, offsets1);
 
-            // Verify that the persisted representations have all been updated
-            int[] offsets = ppt.getPictureData().stream().mapToInt(HSLFPictureData::getOffset).toArray();
-            assertArrayEquals(modifiedOffsets, offsets);
+            try (HSLFSlideShow ppt2 = writeOutAndReadBack(ppt1)) {
+                // Verify that the persisted representations have all been updated
+                int[] offsets2 = ppt2.getPictureData().stream().mapToInt(HSLFPictureData::getOffset).toArray();
+                assertArrayEquals(modifiedOffsets, offsets2);
+            }
         }
     }
 
@@ -662,11 +454,9 @@ public final class TestPictures {
     void testEditPictureDataOutOfOrderRecords() throws IOException {
         int[] modifiedOffsets = {0, 35, 3103, 22184, 47585};
 
-        ByteArrayOutputStream inMemory = new ByteArrayOutputStream();
-        try (HSLFSlideShow ppt = HSLFTestDataSamples.getSlideShow("pictures.ppt")) {
-
+        try (HSLFSlideShow ppt1 = getSlideShow("pictures.ppt")) {
             // For this test we're going to intentionally manipulate the records into a shuffled order.
-            EscherContainerRecord container = ppt.getPictureData().get(0).bStore;
+            EscherContainerRecord container = ppt1.getPictureData().get(0).bStore;
             List<EscherRecord> children = container.getChildRecords();
             for (EscherRecord child : children) {
                 container.removeChildRecord(child);
@@ -676,25 +466,21 @@ public final class TestPictures {
                 container.addChildRecord(child);
             }
 
-            HSLFPictureData imageBeingChanged = ppt.getPictureData().get(0);
+            HSLFPictureData imageBeingChanged = ppt1.getPictureData().get(0);
             // It doesn't matter that this isn't a valid image. We are just testing offsets here.
             imageBeingChanged.setData(new byte[10]);
 
             // Verify that the in-memory representations have all been updated
-            int[] offsets = ppt.getPictureData().stream().mapToInt(HSLFPictureData::getOffset).toArray();
-            Arrays.sort(offsets);
-            assertArrayEquals(modifiedOffsets, offsets);
+            int[] offsets1 = ppt1.getPictureData().stream().mapToInt(HSLFPictureData::getOffset).sorted().toArray();
+            assertArrayEquals(modifiedOffsets, offsets1);
 
-            ppt.write(inMemory);
+            try (HSLFSlideShow ppt2 = writeOutAndReadBack(ppt1)) {
+                // Verify that the persisted representations have all been updated
+                int[] offsets2 = ppt2.getPictureData().stream().mapToInt(HSLFPictureData::getOffset).sorted().toArray();
+                assertArrayEquals(modifiedOffsets, offsets2);
+            }
         }
 
-        try (HSLFSlideShow ppt = new HSLFSlideShow(new ByteArrayInputStream(inMemory.toByteArray()))) {
-
-            // Verify that the persisted representations have all been updated
-            int[] offsets = ppt.getPictureData().stream().mapToInt(HSLFPictureData::getOffset).toArray();
-            Arrays.sort(offsets);
-            assertArrayEquals(modifiedOffsets, offsets);
-        }
     }
 
     /**
@@ -707,28 +493,25 @@ public final class TestPictures {
         int originalNumberOfRecords;
 
         // Create a presentation that has records with unmatched offsets, but with matched UIDs.
-        ByteArrayOutputStream inMemory = new ByteArrayOutputStream();
-        try (HSLFSlideShow ppt = HSLFTestDataSamples.getSlideShow("pictures.ppt")) {
-            originalOffsets = ppt.getPictureData().stream().mapToInt(HSLFPictureData::getOffset).toArray();
-            originalNumberOfRecords = ppt.getPictureData().get(0).bStore.getChildCount();
+        try (HSLFSlideShow ppt1 = getSlideShow("pictures.ppt")) {
+            originalOffsets = ppt1.getPictureData().stream().mapToInt(HSLFPictureData::getOffset).toArray();
+            originalNumberOfRecords = ppt1.getPictureData().get(0).bStore.getChildCount();
 
             Random random = new Random();
-            for (HSLFPictureData picture : ppt.getPictureData()) {
+            for (HSLFPictureData picture : ppt1.getPictureData()) {
                 // Bound is arbitrary and irrelevant to the test.
                 picture.bse.setOffset(random.nextInt(500_000));
             }
-            ppt.write(inMemory);
-        }
 
-        try (HSLFSlideShow ppt = new HSLFSlideShow(new ByteArrayInputStream(inMemory.toByteArray()))) {
+            try (HSLFSlideShow ppt2 = writeOutAndReadBack(ppt1)) {
+                // Verify that the offsets all got fixed.
+                int[] offsets = ppt2.getPictureData().stream().mapToInt(HSLFPictureData::getOffset).toArray();
+                assertArrayEquals(originalOffsets, offsets);
 
-            // Verify that the offsets all got fixed.
-            int[] offsets = ppt.getPictureData().stream().mapToInt(HSLFPictureData::getOffset).toArray();
-            assertArrayEquals(originalOffsets, offsets);
-
-            // Verify that there are the same number of records as in the original slideshow.
-            int numberOfRecords = ppt.getPictureData().get(0).bStore.getChildCount();
-            assertEquals(originalNumberOfRecords, numberOfRecords);
+                // Verify that there are the same number of records as in the original slideshow.
+                int numberOfRecords = ppt2.getPictureData().get(0).bStore.getChildCount();
+                assertEquals(originalNumberOfRecords, numberOfRecords);
+            }
         }
     }
 }
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hslf/usermodel/TestRichTextRun.java b/poi-scratchpad/src/test/java/org/apache/poi/hslf/usermodel/TestRichTextRun.java
index 8081528a9f..90a84b815e 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hslf/usermodel/TestRichTextRun.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hslf/usermodel/TestRichTextRun.java
@@ -24,12 +24,11 @@ import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.util.List;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.hslf.HSLFTestDataSamples;
 import org.apache.poi.hslf.record.Record;
 import org.apache.poi.hslf.record.SlideListWithText;
@@ -230,30 +229,30 @@ public final class TestRichTextRun {
 			assertEquals("Courier", rtr.getFontFamily());
 
 			// Write out and back in
-			HSLFSlideShow readS = HSLFTestDataSamples.writeOutAndReadBack(h);
-
-			// Tweak existing one again, to ensure really worked
-			rtr.setBold(false);
-			rtr.setFontSize(17d);
-			rtr.setFontFamily("CourierZZ");
-
-			// Check it took those changes
-			assertFalse(rtr.isBold());
-			assertEquals(17., rtr.getFontSize(), 0);
-			assertEquals("CourierZZ", rtr.getFontFamily());
-
-
-			// Now, look at the one we changed, wrote out, and read back in
-			// Ensure it does contain our original modifications
-			HSLFSlide slideOneRR = readS.getSlides().get(0);
-			List<List<HSLFTextParagraph>> textParassRR = slideOneRR.getTextParagraphs();
-			HSLFTextRun rtrRRa = textParassRR.get(0).get(0).getTextRuns().get(0);
-
-			assertTrue(rtrRRa.isBold());
-			assertNotNull(rtrRRa.getFontSize());
-			assertEquals(18., rtrRRa.getFontSize(), 0);
-			assertEquals("Courier", rtrRRa.getFontFamily());
-			readS.close();
+			try (HSLFSlideShow readS = HSLFTestDataSamples.writeOutAndReadBack(h)) {
+
+				// Tweak existing one again, to ensure really worked
+				rtr.setBold(false);
+				rtr.setFontSize(17d);
+				rtr.setFontFamily("CourierZZ");
+
+				// Check it took those changes
+				assertFalse(rtr.isBold());
+				assertEquals(17., rtr.getFontSize(), 0);
+				assertEquals("CourierZZ", rtr.getFontFamily());
+
+
+				// Now, look at the one we changed, wrote out, and read back in
+				// Ensure it does contain our original modifications
+				HSLFSlide slideOneRR = readS.getSlides().get(0);
+				List<List<HSLFTextParagraph>> textParassRR = slideOneRR.getTextParagraphs();
+				HSLFTextRun rtrRRa = textParassRR.get(0).get(0).getTextRuns().get(0);
+
+				assertTrue(rtrRRa.isBold());
+				assertNotNull(rtrRRa.getFontSize());
+				assertEquals(18., rtrRRa.getFontSize(), 0);
+				assertEquals("Courier", rtrRRa.getFontFamily());
+			}
 		}
 	}
 
@@ -370,29 +369,30 @@ public final class TestRichTextRun {
 	 */
 	private void assertMatchesSLTWC(HSLFSlideShow s) throws IOException {
 		// Grab a new copy of slideshow C
-		HSLFSlideShow refC = HSLFTestDataSamples.getSlideShow(filenameC);
+		try (HSLFSlideShow refC = HSLFTestDataSamples.getSlideShow(filenameC)) {
 
-		// Write out the 2nd SLWT in the active document
-		SlideListWithText refSLWT = refC.getDocumentRecord().getSlideListWithTexts()[1];
-		byte[] raw_slwt = writeRecord(refSLWT);
+			// Write out the 2nd SLWT in the active document
+			SlideListWithText refSLWT = refC.getDocumentRecord().getSlideListWithTexts()[1];
+			byte[] raw_slwt = writeRecord(refSLWT);
 
-		// Write out the same for the supplied slideshow
-		SlideListWithText s_SLWT = s.getDocumentRecord().getSlideListWithTexts()[1];
-		byte[] s_slwt = writeRecord(s_SLWT);
+			// Write out the same for the supplied slideshow
+			SlideListWithText s_SLWT = s.getDocumentRecord().getSlideListWithTexts()[1];
+			byte[] s_slwt = writeRecord(s_SLWT);
 
-		// Check the records are the same
-		assertEquals(refSLWT.getChildRecords().length, s_SLWT.getChildRecords().length);
-		for(int i=0; i<refSLWT.getChildRecords().length; i++) {
-			Record ref_r = refSLWT.getChildRecords()[i];
-			Record s_r = s_SLWT.getChildRecords()[i];
+			// Check the records are the same
+			assertEquals(refSLWT.getChildRecords().length, s_SLWT.getChildRecords().length);
+			for (int i = 0; i < refSLWT.getChildRecords().length; i++) {
+				Record ref_r = refSLWT.getChildRecords()[i];
+				Record s_r = s_SLWT.getChildRecords()[i];
 
-			byte[] r_rb = writeRecord(ref_r);
-			byte[] s_rb = writeRecord(s_r);
-			assertArrayEquals(r_rb, s_rb);
-		}
+				byte[] r_rb = writeRecord(ref_r);
+				byte[] s_rb = writeRecord(s_r);
+				assertArrayEquals(r_rb, s_rb);
+			}
 
-		// Check the bytes are the same
-		assertArrayEquals(raw_slwt, s_slwt);
+			// Check the bytes are the same
+			assertArrayEquals(raw_slwt, s_slwt);
+		}
 	}
 
 	/**
@@ -401,20 +401,20 @@ public final class TestRichTextRun {
 	 */
 	private static void assertMatchesFileC(HSLFSlideShow s) throws IOException {
 		// Grab the bytes of the file
-	    POIFSFileSystem fs = new POIFSFileSystem(HSLFTestDataSamples.openSampleFileStream(filenameC));
-	    InputStream is = fs.createDocumentInputStream(HSLFSlideShow.POWERPOINT_DOCUMENT);
-	    byte[] raw_file = IOUtils.toByteArray(is);
-	    is.close();
-	    fs.close();
+		byte[] raw_file;
+	    try (POIFSFileSystem fs = new POIFSFileSystem(HSLFTestDataSamples.openSampleFileStream(filenameC));
+	    	InputStream is = fs.createDocumentInputStream(HSLFSlideShow.POWERPOINT_DOCUMENT)) {
+			raw_file = IOUtils.toByteArray(is);
+		}
 
 		// Now write out the slideshow
-        ByteArrayOutputStream baos = new ByteArrayOutputStream();
+		byte[] raw_ss;
+        UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
 		s.write(baos);
-		fs = new POIFSFileSystem(new ByteArrayInputStream(baos.toByteArray()));
-		is = fs.createDocumentInputStream(HSLFSlideShow.POWERPOINT_DOCUMENT);
-		byte[] raw_ss = IOUtils.toByteArray(is);
-        is.close();
-        fs.close();
+		try (POIFSFileSystem fs = new POIFSFileSystem(baos.toInputStream());
+			InputStream is = fs.createDocumentInputStream(HSLFSlideShow.POWERPOINT_DOCUMENT)) {
+			raw_ss = IOUtils.toByteArray(is);
+		}
 
 		// different paragraph mask, because of sanitizing
 		raw_ss[169030] = 0x0a;
@@ -424,24 +424,24 @@ public final class TestRichTextRun {
 	}
 
 	private byte[] writeRecord( org.apache.poi.hslf.record.Record r) throws IOException {
-		ByteArrayOutputStream baos = new ByteArrayOutputStream();
+		UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
 		r.writeOut(baos);
 		return baos.toByteArray();
 	}
 
     @Test
 	void testIndentationLevel() throws Exception {
-		HSLFSlideShow ppt = HSLFTestDataSamples.getSlideShow("ParagraphStylesShorterThanCharStyles.ppt");
-		for (HSLFSlide sl : ppt.getSlides()) {
-			for (List<HSLFTextParagraph> txt : sl.getTextParagraphs()) {
-				for (HSLFTextParagraph p : txt) {
-					int indent = p.getIndentLevel();
-					assertTrue(indent >= 0 && indent <= 4 );
-				}
+		try (HSLFSlideShow ppt = HSLFTestDataSamples.getSlideShow("ParagraphStylesShorterThanCharStyles.ppt")) {
+			for (HSLFSlide sl : ppt.getSlides()) {
+				for (List<HSLFTextParagraph> txt : sl.getTextParagraphs()) {
+					for (HSLFTextParagraph p : txt) {
+						int indent = p.getIndentLevel();
+						assertTrue(indent >= 0 && indent <= 4);
+					}
 
+				}
 			}
 		}
-		ppt.close();
 	}
 
     @Test
@@ -502,54 +502,54 @@ public final class TestRichTextRun {
 
     @Test
 	void testSetParagraphStyles() throws IOException {
-		HSLFSlideShow ppt1 = new HSLFSlideShow();
+		try (HSLFSlideShow ppt1 = new HSLFSlideShow()) {
 
-		HSLFSlide slide = ppt1.createSlide();
+			HSLFSlide slide = ppt1.createSlide();
 
-		HSLFTextBox shape = new HSLFTextBox();
-		shape.setText(
+			HSLFTextBox shape = new HSLFTextBox();
+			shape.setText(
 				"Hello, World!\r" +
-				"This should be\r" +
-				"Multiline text");
-        HSLFTextParagraph rt = shape.getTextParagraphs().get(0);
-        HSLFTextRun tr = rt.getTextRuns().get(0);
-		tr.setFontSize(42d);
-		rt.setBullet(true);
-		rt.setLeftMargin(50d);
-		rt.setIndent(0d);
-		rt.setBulletChar('\u263A');
-		slide.addShape(shape);
-
-		assertNotNull(tr.getFontSize());
-		assertEquals(42.0, tr.getFontSize(), 0);
-		assertTrue(rt.isBullet());
-		assertNotNull(rt.getLeftMargin());
-		assertEquals(50.0, rt.getLeftMargin(), 0);
-		assertNotNull(rt.getIndent());
-		assertEquals(0, rt.getIndent(), 0);
-		assertNotNull(rt.getBulletChar());
-		assertEquals('\u263A', (char)rt.getBulletChar());
-
-		shape.setAnchor(new java.awt.Rectangle(50, 50, 500, 300));
-		slide.addShape(shape);
-
-		//serialize and read again
-		HSLFSlideShow ppt2 = HSLFTestDataSamples.writeOutAndReadBack(ppt1);
-		slide = ppt2.getSlides().get(0);
-		shape = (HSLFTextBox)slide.getShapes().get(0);
-		rt = shape.getTextParagraphs().get(0);
-		tr = rt.getTextRuns().get(0);
-		assertNotNull(tr.getFontSize());
-		assertEquals(42.0, tr.getFontSize(), 0);
-		assertTrue(rt.isBullet());
-		assertNotNull(rt.getLeftMargin());
-		assertEquals(50.0, rt.getLeftMargin(), 0);
-		assertNotNull(rt.getIndent());
-		assertEquals(0, rt.getIndent(), 0);
-		assertNotNull(rt.getBulletChar());
-		assertEquals('\u263A', (char)rt.getBulletChar());
-		ppt2.close();
-		ppt1.close();
+					"This should be\r" +
+					"Multiline text");
+			HSLFTextParagraph rt = shape.getTextParagraphs().get(0);
+			HSLFTextRun tr = rt.getTextRuns().get(0);
+			tr.setFontSize(42d);
+			rt.setBullet(true);
+			rt.setLeftMargin(50d);
+			rt.setIndent(0d);
+			rt.setBulletChar('\u263A');
+			slide.addShape(shape);
+
+			assertNotNull(tr.getFontSize());
+			assertEquals(42.0, tr.getFontSize(), 0);
+			assertTrue(rt.isBullet());
+			assertNotNull(rt.getLeftMargin());
+			assertEquals(50.0, rt.getLeftMargin(), 0);
+			assertNotNull(rt.getIndent());
+			assertEquals(0, rt.getIndent(), 0);
+			assertNotNull(rt.getBulletChar());
+			assertEquals('\u263A', (char) rt.getBulletChar());
+
+			shape.setAnchor(new java.awt.Rectangle(50, 50, 500, 300));
+			slide.addShape(shape);
+
+			//serialize and read again
+			try (HSLFSlideShow ppt2 = HSLFTestDataSamples.writeOutAndReadBack(ppt1)) {
+				slide = ppt2.getSlides().get(0);
+				shape = (HSLFTextBox) slide.getShapes().get(0);
+				rt = shape.getTextParagraphs().get(0);
+				tr = rt.getTextRuns().get(0);
+				assertNotNull(tr.getFontSize());
+				assertEquals(42.0, tr.getFontSize(), 0);
+				assertTrue(rt.isBullet());
+				assertNotNull(rt.getLeftMargin());
+				assertEquals(50.0, rt.getLeftMargin(), 0);
+				assertNotNull(rt.getIndent());
+				assertEquals(0, rt.getIndent(), 0);
+				assertNotNull(rt.getBulletChar());
+				assertEquals('\u263A', (char) rt.getBulletChar());
+			}
+		}
 	}
 
     @Test
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hslf/usermodel/TestTable.java b/poi-scratchpad/src/test/java/org/apache/poi/hslf/usermodel/TestTable.java
index 1176003e7a..437cb592ff 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hslf/usermodel/TestTable.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hslf/usermodel/TestTable.java
@@ -19,6 +19,7 @@
 
 package org.apache.poi.hslf.usermodel;
 
+import static org.apache.poi.hslf.HSLFTestDataSamples.writeOutAndReadBack;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
@@ -26,8 +27,6 @@ import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.awt.Color;
 import java.awt.geom.Rectangle2D;
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.util.List;
 
@@ -108,58 +107,49 @@ public class TestTable {
 
     @Test
     void testAddText() throws IOException {
-        HSLFSlideShow ppt1 = new HSLFSlideShow();
-        HSLFSlide slide = ppt1.createSlide();
-        HSLFTable tab = slide.createTable(4, 5);
-
-        int rows = tab.getNumberOfRows();
-        int cols = tab.getNumberOfColumns();
-        for (int row=0; row<rows; row++) {
-            for (int col=0; col<cols; col++) {
-                HSLFTableCell c = tab.getCell(row, col);
-                assertNotNull(c);
-                c.setText("r"+(row+1)+"c"+(col+1));
+        try (HSLFSlideShow ppt1 = new HSLFSlideShow()) {
+            HSLFSlide slide = ppt1.createSlide();
+            HSLFTable tab = slide.createTable(4, 5);
+
+            int rows = tab.getNumberOfRows();
+            int cols = tab.getNumberOfColumns();
+            for (int row = 0; row < rows; row++) {
+                for (int col = 0; col < cols; col++) {
+                    HSLFTableCell c = tab.getCell(row, col);
+                    assertNotNull(c);
+                    c.setText("r" + (row + 1) + "c" + (col + 1));
+                }
             }
-        }
 
-        ByteArrayOutputStream bos = new ByteArrayOutputStream();
-        ppt1.write(bos);
-        ppt1.close();
-
-        ByteArrayInputStream bis = new ByteArrayInputStream(bos.toByteArray());
-        HSLFSlideShow ppt2 = new HSLFSlideShow(bis);
-        slide = ppt2.getSlides().get(0);
-        tab = (HSLFTable)slide.getShapes().get(0);
-
-        rows = tab.getNumberOfRows();
-        cols = tab.getNumberOfColumns();
-        for (int row=0; row<rows; row++) {
-            for (int col=0; col<cols; col++) {
-                HSLFTableCell c = tab.getCell(row, col);
-                assertNotNull(c);
-                c.setText(c.getText()+"...");
+            try (HSLFSlideShow ppt2 = writeOutAndReadBack(ppt1)) {
+                slide = ppt2.getSlides().get(0);
+                tab = (HSLFTable) slide.getShapes().get(0);
+
+                rows = tab.getNumberOfRows();
+                cols = tab.getNumberOfColumns();
+                for (int row = 0; row < rows; row++) {
+                    for (int col = 0; col < cols; col++) {
+                        HSLFTableCell c = tab.getCell(row, col);
+                        assertNotNull(c);
+                        c.setText(c.getText() + "...");
+                    }
+                }
+
+                try (HSLFSlideShow ppt3 = writeOutAndReadBack(ppt2)) {
+                    slide = ppt3.getSlides().get(0);
+                    tab = (HSLFTable) slide.getShapes().get(0);
+
+                    rows = tab.getNumberOfRows();
+                    cols = tab.getNumberOfColumns();
+                    for (int row = 0; row < rows; row++) {
+                        for (int col = 0; col < cols; col++) {
+                            HSLFTableCell c = tab.getCell(row, col);
+                            assertNotNull(c);
+                            assertEquals("r" + (row + 1) + "c" + (col + 1) + "...", c.getText());
+                        }
+                    }
+                }
             }
         }
-
-        bos.reset();
-        ppt2.write(bos);
-        ppt2.close();
-
-        bis = new ByteArrayInputStream(bos.toByteArray());
-        HSLFSlideShow ppt3 = new HSLFSlideShow(bis);
-        slide = ppt3.getSlides().get(0);
-        tab = (HSLFTable)slide.getShapes().get(0);
-
-        rows = tab.getNumberOfRows();
-        cols = tab.getNumberOfColumns();
-        for (int row=0; row<rows; row++) {
-            for (int col=0; col<cols; col++) {
-                HSLFTableCell c = tab.getCell(row, col);
-                assertNotNull(c);
-                assertEquals("r"+(row+1)+"c"+(col+1)+"...", c.getText());
-            }
-        }
-
-        ppt3.close();
     }
 }
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hslf/usermodel/TestTextShape.java b/poi-scratchpad/src/test/java/org/apache/poi/hslf/usermodel/TestTextShape.java
index 1b577eb273..10493a6998 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hslf/usermodel/TestTextShape.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hslf/usermodel/TestTextShape.java
@@ -17,27 +17,26 @@
 
 package org.apache.poi.hslf.usermodel;
 
+import static org.apache.poi.hslf.HSLFTestDataSamples.getSlideShow;
+import static org.apache.poi.hslf.HSLFTestDataSamples.writeOutAndReadBack;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertNull;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 import static org.junit.jupiter.api.Assertions.fail;
 
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 
-import org.apache.poi.hslf.HSLFTestDataSamples;
 import org.apache.poi.sl.usermodel.ShapeType;
 import org.apache.poi.sl.usermodel.TextShape.TextPlaceholder;
 import org.junit.jupiter.api.Test;
 
 /**
- * Verify behavior of <code>TextShape</code> and its sub-classes
+ * Verify behavior of {@code TextShape} and its sub-classes
  */
 public final class TestTextShape {
     @Test
@@ -72,153 +71,146 @@ public final class TestTextShape {
      */
     @Test
     void read() throws IOException {
-        HSLFSlideShow ppt = HSLFTestDataSamples.getSlideShow("text_shapes.ppt");
-
-        List<String> lst1 = new ArrayList<>();
-        HSLFSlide slide = ppt.getSlides().get(0);
-        for (HSLFShape shape : slide.getShapes()) {
-            assertTrue(shape instanceof HSLFTextShape, "Expected TextShape but found " + shape.getClass().getName());
-            HSLFTextShape tx = (HSLFTextShape)shape;
-            List<HSLFTextParagraph> paras = tx.getTextParagraphs();
-            assertNotNull(paras);
-            int runType = paras.get(0).getRunType();
-
-            ShapeType type = shape.getShapeType();
-            String rawText = HSLFTextParagraph.getRawText(paras);
-            switch (type){
-                case TEXT_BOX:
-                    assertEquals("Text in a TextBox", rawText);
-                    break;
-                case RECT:
-                    if(runType == TextPlaceholder.OTHER.nativeId) {
-                        assertEquals("Rectangle", rawText);
-                    } else if(runType == TextPlaceholder.TITLE.nativeId) {
-                        assertEquals("Title Placeholder", rawText);
-                    }
-                    break;
-                case OCTAGON:
-                    assertEquals("Octagon", rawText);
-                    break;
-                case ELLIPSE:
-                    assertEquals("Ellipse", rawText);
-                    break;
-                case ROUND_RECT:
-                    assertEquals("RoundRectangle", rawText);
-                    break;
-                default:
-                    fail("Unexpected shape: " + shape.getShapeName());
+        try (HSLFSlideShow ppt = getSlideShow("text_shapes.ppt")) {
+
+            List<String> lst1 = new ArrayList<>();
+            HSLFSlide slide = ppt.getSlides().get(0);
+            for (HSLFShape shape : slide.getShapes()) {
+                assertTrue(shape instanceof HSLFTextShape, "Expected TextShape but found " + shape.getClass().getName());
+                HSLFTextShape tx = (HSLFTextShape) shape;
+                List<HSLFTextParagraph> paras = tx.getTextParagraphs();
+                assertNotNull(paras);
+                int runType = paras.get(0).getRunType();
+
+                ShapeType type = shape.getShapeType();
+                String rawText = HSLFTextParagraph.getRawText(paras);
+                switch (type) {
+                    case TEXT_BOX:
+                        assertEquals("Text in a TextBox", rawText);
+                        break;
+                    case RECT:
+                        if (runType == TextPlaceholder.OTHER.nativeId) {
+                            assertEquals("Rectangle", rawText);
+                        } else if (runType == TextPlaceholder.TITLE.nativeId) {
+                            assertEquals("Title Placeholder", rawText);
+                        }
+                        break;
+                    case OCTAGON:
+                        assertEquals("Octagon", rawText);
+                        break;
+                    case ELLIPSE:
+                        assertEquals("Ellipse", rawText);
+                        break;
+                    case ROUND_RECT:
+                        assertEquals("RoundRectangle", rawText);
+                        break;
+                    default:
+                        fail("Unexpected shape: " + shape.getShapeName());
+
+                }
+                lst1.add(rawText);
+            }
 
+            List<String> lst2 = new ArrayList<>();
+            for (List<HSLFTextParagraph> paras : slide.getTextParagraphs()) {
+                lst2.add(HSLFTextParagraph.getRawText(paras));
             }
-            lst1.add(rawText);
-        }
 
-        List<String> lst2 = new ArrayList<>();
-        for (List<HSLFTextParagraph> paras : slide.getTextParagraphs()) {
-            lst2.add(HSLFTextParagraph.getRawText(paras));
+            assertTrue(lst1.containsAll(lst2));
         }
-
-        assertTrue(lst1.containsAll(lst2));
-        ppt.close();
     }
 
     @Test
     void readWrite() throws IOException {
-        HSLFSlideShow ppt = new HSLFSlideShow();
-        HSLFSlide slide =  ppt.createSlide();
-
-        HSLFTextShape shape1 = new HSLFTextBox();
-        shape1.setText("Hello, World!");
-        slide.addShape(shape1);
-
-        shape1.moveTo(100, 100);
-
-        HSLFTextShape shape2 = new HSLFAutoShape(ShapeType.RIGHT_ARROW);
-        shape2.setText("Testing TextShape");
-        slide.addShape(shape2);
-        shape2.moveTo(300, 300);
-
-        ByteArrayOutputStream out = new ByteArrayOutputStream();
-        ppt.write(out);
-        out.close();
-
-        ppt = new HSLFSlideShow(new ByteArrayInputStream(out.toByteArray()));
-        slide = ppt.getSlides().get(0);
-        List<HSLFShape> shape = slide.getShapes();
-
-        assertTrue(shape.get(0) instanceof HSLFTextShape);
-        shape1 = (HSLFTextShape)shape.get(0);
-        assertEquals(ShapeType.TEXT_BOX, shape1.getShapeType());
-        assertEquals("Hello, World!", shape1.getText());
-
-        assertTrue(shape.get(1) instanceof HSLFTextShape);
-        shape1 = (HSLFTextShape)shape.get(1);
-        assertEquals(ShapeType.RIGHT_ARROW, shape1.getShapeType());
-        assertEquals("Testing TextShape", shape1.getText());
-        ppt.close();
-    }
+        try (HSLFSlideShow ppt1 = new HSLFSlideShow()) {
+            HSLFSlide slide = ppt1.createSlide();
 
-    @Test
-    void margins() throws IOException {
-        HSLFSlideShow ppt = HSLFTestDataSamples.getSlideShow("text-margins.ppt");
+            HSLFTextShape shape1 = new HSLFTextBox();
+            shape1.setText("Hello, World!");
+            slide.addShape(shape1);
+
+            shape1.moveTo(100, 100);
+
+            HSLFTextShape shape2 = new HSLFAutoShape(ShapeType.RIGHT_ARROW);
+            shape2.setText("Testing TextShape");
+            slide.addShape(shape2);
+            shape2.moveTo(300, 300);
+
+            try (HSLFSlideShow ppt2 = writeOutAndReadBack(ppt1)) {
+                slide = ppt2.getSlides().get(0);
+                List<HSLFShape> shape = slide.getShapes();
 
-        HSLFSlide slide = ppt.getSlides().get(0);
+                assertTrue(shape.get(0) instanceof HSLFTextShape);
+                shape1 = (HSLFTextShape) shape.get(0);
+                assertEquals(ShapeType.TEXT_BOX, shape1.getShapeType());
+                assertEquals("Hello, World!", shape1.getText());
 
-        Map<String,HSLFTextShape> map = new HashMap<>();
-        for (HSLFShape shape : slide.getShapes()) {
-            if(shape instanceof HSLFTextShape){
-                HSLFTextShape tx = (HSLFTextShape)shape;
-                map.put(tx.getText(), tx);
+                assertTrue(shape.get(1) instanceof HSLFTextShape);
+                shape1 = (HSLFTextShape) shape.get(1);
+                assertEquals(ShapeType.RIGHT_ARROW, shape1.getShapeType());
+                assertEquals("Testing TextShape", shape1.getText());
             }
         }
-
-        HSLFTextShape tx;
-
-        tx = map.get("TEST1");
-        assertEquals(7.2, tx.getLeftInset(), 0);
-        assertEquals(7.2, tx.getRightInset(), 0);
-        assertEquals(28.34, tx.getTopInset(), 0.01);
-        assertEquals(3.6, tx.getBottomInset(), 0);
-
-        tx = map.get("TEST2");
-        assertEquals(7.2, tx.getLeftInset(), 0);
-        assertEquals(7.2, tx.getRightInset(), 0);
-        assertEquals(3.6, tx.getTopInset(), 0);
-        assertEquals(28.34, tx.getBottomInset(), 0.01);
-
-        tx = map.get("TEST3");
-        assertEquals(28.34, tx.getLeftInset(), 0.01);
-        assertEquals(7.2, tx.getRightInset(), 0);
-        assertEquals(3.6, tx.getTopInset(), 0);
-        assertEquals(3.6, tx.getBottomInset(), 0);
-
-        tx = map.get("TEST4");
-        assertEquals(7.2, tx.getLeftInset(), 0);
-        assertEquals(28.34, tx.getRightInset(), 0.01);
-        assertEquals(3.6, tx.getTopInset(), 0);
-        assertEquals(3.6, tx.getBottomInset(), 0);
-
-        ppt.close();
     }
 
     @Test
-    void bug52599() throws IOException {
-        HSLFSlideShow ppt = HSLFTestDataSamples.getSlideShow("52599.ppt");
+    void margins() throws IOException {
+        try (HSLFSlideShow ppt = getSlideShow("text-margins.ppt")) {
 
-        HSLFSlide slide = ppt.getSlides().get(0);
-        List<HSLFShape> sh = slide.getShapes();
-        assertEquals(3, sh.size());
+            HSLFSlide slide = ppt.getSlides().get(0);
 
-        HSLFTextShape sh0 = (HSLFTextShape)sh.get(0);
-        assertNotNull(sh0.getTextParagraphs());
-        assertEquals("", sh0.getText());
+            Map<String, HSLFTextShape> map = new HashMap<>();
+            for (HSLFShape shape : slide.getShapes()) {
+                if (shape instanceof HSLFTextShape) {
+                    HSLFTextShape tx = (HSLFTextShape) shape;
+                    map.put(tx.getText(), tx);
+                }
+            }
 
-        HSLFTextShape sh1 = (HSLFTextShape)sh.get(1);
-        assertNotNull(sh1.getTextParagraphs());
-        assertEquals("", sh1.getText());
+            HSLFTextShape tx = map.get("TEST1");
+            assertEquals(7.2, tx.getLeftInset(), 0);
+            assertEquals(7.2, tx.getRightInset(), 0);
+            assertEquals(28.34, tx.getTopInset(), 0.01);
+            assertEquals(3.6, tx.getBottomInset(), 0);
+
+            tx = map.get("TEST2");
+            assertEquals(7.2, tx.getLeftInset(), 0);
+            assertEquals(7.2, tx.getRightInset(), 0);
+            assertEquals(3.6, tx.getTopInset(), 0);
+            assertEquals(28.34, tx.getBottomInset(), 0.01);
+
+            tx = map.get("TEST3");
+            assertEquals(28.34, tx.getLeftInset(), 0.01);
+            assertEquals(7.2, tx.getRightInset(), 0);
+            assertEquals(3.6, tx.getTopInset(), 0);
+            assertEquals(3.6, tx.getBottomInset(), 0);
+
+            tx = map.get("TEST4");
+            assertEquals(7.2, tx.getLeftInset(), 0);
+            assertEquals(28.34, tx.getRightInset(), 0.01);
+            assertEquals(3.6, tx.getTopInset(), 0);
+            assertEquals(3.6, tx.getBottomInset(), 0);
+        }
+    }
 
-        HSLFTextShape sh2 = (HSLFTextShape)sh.get(2);
-        assertEquals("this box should be shown just once", sh2.getText());
-        assertEquals(-1, sh2.getTextParagraphs().get(0).getIndex());
-        ppt.close();
+    @Test
+    void bug52599() throws IOException {
+        try (HSLFSlideShow ppt = getSlideShow("52599.ppt")) {
+            HSLFSlide slide = ppt.getSlides().get(0);
+            List<HSLFShape> sh = slide.getShapes();
+            assertEquals(3, sh.size());
+
+            HSLFTextShape sh0 = (HSLFTextShape) sh.get(0);
+            assertNotNull(sh0.getTextParagraphs());
+            assertEquals("", sh0.getText());
+
+            HSLFTextShape sh1 = (HSLFTextShape) sh.get(1);
+            assertNotNull(sh1.getTextParagraphs());
+            assertEquals("", sh1.getText());
+
+            HSLFTextShape sh2 = (HSLFTextShape) sh.get(2);
+            assertEquals("this box should be shown just once", sh2.getText());
+            assertEquals(-1, sh2.getTextParagraphs().get(0).getIndex());
+        }
     }
 }
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hsmf/TestExtractEmbeddedMSG.java b/poi-scratchpad/src/test/java/org/apache/poi/hsmf/TestExtractEmbeddedMSG.java
index 4f0322b806..a11ba12c90 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hsmf/TestExtractEmbeddedMSG.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hsmf/TestExtractEmbeddedMSG.java
@@ -21,12 +21,12 @@ import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 
 import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.util.Calendar;
 import java.util.Map;
 import java.util.TimeZone;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.POIDataSamples;
 import org.apache.poi.hsmf.datatypes.AttachmentChunks;
 import org.apache.poi.hsmf.datatypes.Chunk;
@@ -54,8 +54,6 @@ public class TestExtractEmbeddedMSG {
 
     /**
      * Initialize this test, load up the attachment_msg_pdf.msg mapi message.
-     *
-     * @throws Exception
      */
     @BeforeAll
     public static void setUp() throws IOException {
@@ -71,9 +69,6 @@ public class TestExtractEmbeddedMSG {
     /**
      * Test to see if embedded message properties can be read, extracted, and
      * re-parsed
-     *
-     * @throws ChunkNotFoundException
-     *
      */
     @Test
     void testEmbeddedMSGProperties() throws IOException, ChunkNotFoundException {
@@ -86,11 +81,9 @@ public class TestExtractEmbeddedMSG {
             testFixedAndVariableLengthPropertiesOfAttachedMSG(attachedMsg);
             // rebuild top level message from embedded message
             try (POIFSFileSystem extractedAttachedMsg = rebuildFromAttached(attachedMsg)) {
-                try (ByteArrayOutputStream extractedAttachedMsgOut = new ByteArrayOutputStream()) {
+                try (UnsynchronizedByteArrayOutputStream extractedAttachedMsgOut = new UnsynchronizedByteArrayOutputStream()) {
                     extractedAttachedMsg.writeFilesystem(extractedAttachedMsgOut);
-                    byte[] extratedAttachedMsgRaw = extractedAttachedMsgOut.toByteArray();
-                    MAPIMessage extractedMsgTopLevel = new MAPIMessage(
-                            new ByteArrayInputStream(extratedAttachedMsgRaw));
+                    MAPIMessage extractedMsgTopLevel = new MAPIMessage(extractedAttachedMsgOut.toInputStream());
                     // test properties of rebuilt embedded message
                     testFixedAndVariableLengthPropertiesOfAttachedMSG(extractedMsgTopLevel);
                 }
@@ -104,7 +97,7 @@ public class TestExtractEmbeddedMSG {
         Calendar messageDate = msg.getMessageDate();
         assertNotNull(messageDate);
         Calendar expectedMessageDate = LocaleUtil.getLocaleCalendar();
-        expectedMessageDate.set(2010, 05, 17, 23, 52, 19); // 2010/06/17 23:52:19 GMT
+        expectedMessageDate.set(2010, Calendar.JUNE, 17, 23, 52, 19); // 2010/06/17 23:52:19 GMT
         expectedMessageDate.setTimeZone(TimeZone.getTimeZone("GMT"));
         expectedMessageDate.set(Calendar.MILLISECOND, 0);
         assertEquals(expectedMessageDate.getTimeInMillis(), messageDate.getTimeInMillis());
@@ -178,7 +171,7 @@ public class TestExtractEmbeddedMSG {
                 MAPIType type = Types.getById(iType);
                 if (type != null && type != Types.UNKNOWN) {
                     MAPIProperty mprop = MAPIProperty.createCustom(chunk.getChunkId(), type, chunk.getEntryName());
-                    ByteArrayOutputStream data = new ByteArrayOutputStream();
+                    UnsynchronizedByteArrayOutputStream data = new UnsynchronizedByteArrayOutputStream();
                     chunk.writeValue(data);
                     PropertyValue pval = new PropertyValue(mprop, MessagePropertiesChunk.PROPERTIES_FLAG_READABLE
                             | MessagePropertiesChunk.PROPERTIES_FLAG_WRITEABLE, data.toByteArray(), type);
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hsmf/TestFileWithAttachmentsRead.java b/poi-scratchpad/src/test/java/org/apache/poi/hsmf/TestFileWithAttachmentsRead.java
index 1d8cc9f98a..068fa10883 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hsmf/TestFileWithAttachmentsRead.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hsmf/TestFileWithAttachmentsRead.java
@@ -22,14 +22,16 @@ import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertNull;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.POIDataSamples;
 import org.apache.poi.hsmf.datatypes.AttachmentChunks;
 import org.junit.jupiter.api.AfterAll;
 import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
 
 /**
  * Tests to verify that we can read attachments from msg file
@@ -74,32 +76,21 @@ public class TestFileWithAttachmentsRead {
     /**
      * Bug 60550: Test to see if we get the correct Content-IDs of inline images`.
      */
-    @Test
-    void testReadContentIDField() throws IOException {
-        AttachmentChunks[] attachments = inlineImgMsgAttachments.getAttachmentFiles();
-
-        AttachmentChunks attachment;
-
-        // Check in Content-ID field
-        attachment = inlineImgMsgAttachments.getAttachmentFiles()[0];
-        assertEquals("image001.png", attachment.getAttachFileName().getValue());
-        assertEquals(".png", attachment.getAttachExtension().getValue());
-        assertEquals("image001.png@01D0A524.96D40F30", attachment.getAttachContentId().getValue());
-
-        attachment = inlineImgMsgAttachments.getAttachmentFiles()[1];
-        assertEquals("image002.png", attachment.getAttachFileName().getValue());
-        assertEquals(".png", attachment.getAttachExtension().getValue());
-        assertEquals("image002.png@01D0A524.96D40F30", attachment.getAttachContentId().getValue());
-
-        attachment = inlineImgMsgAttachments.getAttachmentFiles()[2];
-        assertEquals("image003.png", attachment.getAttachFileName().getValue());
-        assertEquals(".png", attachment.getAttachExtension().getValue());
-        assertEquals("image003.png@01D0A526.B4C739C0", attachment.getAttachContentId().getValue());
-
-        attachment = inlineImgMsgAttachments.getAttachmentFiles()[3];
-        assertEquals("image006.jpg", attachment.getAttachFileName().getValue());
-        assertEquals(".jpg", attachment.getAttachExtension().getValue());
-        assertEquals("image006.jpg@01D0A526.B649E220", attachment.getAttachContentId().getValue());
+    @ParameterizedTest
+    @CsvSource({
+        "0, image001.png@01D0A524.96D40F30",
+        "1, image002.png@01D0A524.96D40F30",
+        "2, image003.png@01D0A526.B4C739C0",
+        "3, image006.jpg@01D0A526.B649E220"
+    })
+    void testReadContentIDField(int index, String contentId) {
+        AttachmentChunks attachment = inlineImgMsgAttachments.getAttachmentFiles()[index];
+        String fileName = contentId.substring(0, contentId.indexOf("@"));
+        String extension = fileName.substring(fileName.lastIndexOf("."));
+
+        assertEquals(fileName, attachment.getAttachFileName().getValue());
+        assertEquals(extension, attachment.getAttachExtension().getValue());
+        assertEquals(contentId, attachment.getAttachContentId().getValue());
     }
 
 
@@ -128,7 +119,7 @@ public class TestFileWithAttachmentsRead {
         assertEquals("test-unicode.doc", attachment.getAttachLongFileName().getValue());
         assertEquals(".doc", attachment.getAttachExtension().getValue());
         assertNull(attachment.getAttachMimeTag());
-        ByteArrayOutputStream attachmentstream = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream attachmentstream = new UnsynchronizedByteArrayOutputStream();
         attachment.getAttachData().writeValue(attachmentstream);
         assertEquals(24064, attachmentstream.size());
         // or compare the hashes of the attachment data
@@ -141,7 +132,7 @@ public class TestFileWithAttachmentsRead {
         assertNull(attachment.getAttachMimeTag());
         // or compare the hashes of the attachment data
         assertEquals(89, attachment.getAttachData().getValue().length);
-        attachmentstream = new ByteArrayOutputStream();
+        attachmentstream.reset();
         attachment.getAttachData().writeValue(attachmentstream);
         assertEquals(89, attachmentstream.size());
     }
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hsmf/TestFixedSizedProperties.java b/poi-scratchpad/src/test/java/org/apache/poi/hsmf/TestFixedSizedProperties.java
index 04131f3a23..74d6d27ec2 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hsmf/TestFixedSizedProperties.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hsmf/TestFixedSizedProperties.java
@@ -24,7 +24,6 @@ import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import java.io.IOException;
 import java.text.SimpleDateFormat;
 import java.util.Calendar;
 import java.util.HashSet;
@@ -33,6 +32,7 @@ import java.util.Locale;
 import java.util.Map;
 import java.util.TimeZone;
 
+import org.apache.commons.io.output.NullPrintStream;
 import org.apache.poi.POIDataSamples;
 import org.apache.poi.hsmf.datatypes.ChunkBasedPropertyValue;
 import org.apache.poi.hsmf.datatypes.Chunks;
@@ -44,7 +44,6 @@ import org.apache.poi.hsmf.dev.HSMFDump;
 import org.apache.poi.hsmf.extractor.OutlookTextExtractor;
 import org.apache.poi.poifs.filesystem.POIFSFileSystem;
 import org.apache.poi.util.LocaleUtil;
-import org.apache.poi.util.NullPrintStream;
 import org.junit.jupiter.api.AfterAll;
 import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.Test;
@@ -167,7 +166,7 @@ public final class TestFixedSizedProperties {
     * Test to see if we can read the Date Chunk with HSMFDump.
     */
    @Test
-   void testReadMessageDateSucceedsWithHSMFDump() throws IOException {
+   void testReadMessageDateSucceedsWithHSMFDump() {
        HSMFDump dump = new HSMFDump(fsMessageSucceeds);
        assertDoesNotThrow(() -> dump.dump(new NullPrintStream()));
    }
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hwpf/HWPFTestCase.java b/poi-scratchpad/src/test/java/org/apache/poi/hwpf/HWPFTestCase.java
index 937bb5367d..fba8bc97c0 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hwpf/HWPFTestCase.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hwpf/HWPFTestCase.java
@@ -17,10 +17,10 @@
 
 package org.apache.poi.hwpf;
 
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
+import java.io.InputStream;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeEach;
 
@@ -29,7 +29,7 @@ public abstract class HWPFTestCase {
 
     @BeforeEach
     void setUp() throws Exception {
-        /** @todo verify the constructors */
+        // @TODO verify the constructors
         _hWPFDocFixture = new HWPFDocFixture(this, getTestFile());
 
         _hWPFDocFixture.setUp();
@@ -40,7 +40,7 @@ public abstract class HWPFTestCase {
     }
 
     @AfterEach
-    void tearDown() throws Exception {
+    void tearDown() {
         if (_hWPFDocFixture != null) {
             _hWPFDocFixture.tearDown();
         }
@@ -49,15 +49,13 @@ public abstract class HWPFTestCase {
     }
 
     public HWPFDocument writeOutAndRead(HWPFDocument doc) {
-        ByteArrayOutputStream baos = new ByteArrayOutputStream();
-        HWPFDocument newDoc;
-        try {
+        try (UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream()) {
             doc.write(baos);
-            ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
-            newDoc = new HWPFDocument(bais);
+            try (InputStream is = baos.toInputStream()) {
+                return new HWPFDocument(is);
+            }
         } catch (IOException e) {
             throw new RuntimeException(e);
         }
-        return newDoc;
     }
 }
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hwpf/HWPFTestDataSamples.java b/poi-scratchpad/src/test/java/org/apache/poi/hwpf/HWPFTestDataSamples.java
index b8f11dc40f..0d6ce9bc8c 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hwpf/HWPFTestDataSamples.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hwpf/HWPFTestDataSamples.java
@@ -16,74 +16,24 @@
 ==================================================================== */
 package org.apache.poi.hwpf;
 
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
-import java.util.zip.ZipInputStream;
 
-import org.apache.logging.log4j.LogManager;
-import org.apache.logging.log4j.Logger;
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.POIDataSamples;
 import org.apache.poi.poifs.filesystem.POIFSFileSystem;
-import org.apache.poi.util.IOUtils;
-
-import static org.apache.logging.log4j.util.Unbox.box;
 
 public class HWPFTestDataSamples {
-
-    private static final Logger LOG = LogManager.getLogger(HWPFTestDataSamples.class);
+    private static final POIDataSamples SAMPLES = POIDataSamples.getDocumentInstance();
 
     public static HWPFDocument openSampleFile(String sampleFileName) {
-        try {
-            InputStream is = POIDataSamples.getDocumentInstance().openResourceAsStream(sampleFileName);
-            try {
-                return new HWPFDocument(is);
-            } catch (Throwable e) {
-                is.close();
-                throw e;
-            }
+        try (InputStream is = SAMPLES.openResourceAsStream(sampleFileName)) {
+            return new HWPFDocument(is);
         } catch (IOException e) {
             throw new RuntimeException(e);
         }
     }
 
-    public static HWPFDocument openSampleFileFromArchive( String sampleFileName )
-    {
-        final long start = System.currentTimeMillis();
-        try
-        {
-            try (ZipInputStream is = new ZipInputStream(POIDataSamples
-                    .getDocumentInstance()
-                    .openResourceAsStream(sampleFileName))) {
-                is.getNextEntry();
-                ByteArrayOutputStream baos = new ByteArrayOutputStream();
-                try {
-                    IOUtils.copy(is, baos);
-                } finally {
-                    baos.close();
-                }
-
-                final long endUnzip = System.currentTimeMillis();
-                byte[] byteArray = baos.toByteArray();
-
-                LOG.atDebug().log("Unzipped in {} ms -- {} byte(s)", box(endUnzip - start),box(byteArray.length));
-
-                ByteArrayInputStream bais = new ByteArrayInputStream(byteArray);
-                HWPFDocument doc = new HWPFDocument(bais);
-                final long endParse = System.currentTimeMillis();
-
-                LOG.atDebug().log("Parsed in {} ms", box(endParse - start));
-
-                return doc;
-            }
-        }
-        catch ( IOException e )
-        {
-            throw new RuntimeException( e );
-        }
-    }
-
     public static HWPFOldDocument openOldSampleFile(String sampleFileName) {
        try {
            InputStream is = POIDataSamples.getDocumentInstance().openResourceAsStream(sampleFileName);
@@ -98,11 +48,9 @@ public class HWPFTestDataSamples {
      * Useful for verifying that the serialisation round trip
      */
     public static HWPFDocument writeOutAndReadBack(HWPFDocument original) {
-        try {
-            ByteArrayOutputStream baos = new ByteArrayOutputStream(4096);
+        try (UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream(4096)) {
             original.write(baos);
-            ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
-            return new HWPFDocument(bais);
+            return new HWPFDocument(baos.toInputStream());
         } catch (IOException e) {
             throw new RuntimeException(e);
         }
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hwpf/dev/TestHWPFLister.java b/poi-scratchpad/src/test/java/org/apache/poi/hwpf/dev/TestHWPFLister.java
index 3a94a3efb4..c7cd45c1cc 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hwpf/dev/TestHWPFLister.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hwpf/dev/TestHWPFLister.java
@@ -22,7 +22,7 @@ import java.io.PrintStream;
 import java.util.Arrays;
 
 import org.apache.poi.POIDataSamples;
-import org.apache.poi.util.NullPrintStream;
+import org.apache.commons.io.output.NullPrintStream;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.ValueSource;
 
@@ -38,7 +38,7 @@ public class TestHWPFLister {
         "",
         " --dop --textPieces --textPiecesText --chpx --chpxProperties --chpxSprms --papx --papxProperties --papxSprms --paragraphs --paragraphsText --bookmarks --escher --fields --pictures --officeDrawings --styles --writereadback"
     })
-    void main(String args) throws Exception {
+    void main(String args) {
         String fileArgs = SAMPLES.getFile("SampleDoc.doc").getAbsolutePath() + args;
 
         PrintStream oldStdOut = System.out;
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hwpf/model/TestSavedByTable.java b/poi-scratchpad/src/test/java/org/apache/poi/hwpf/model/TestSavedByTable.java
index 0ae2e4a87a..b98f5208a0 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hwpf/model/TestSavedByTable.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hwpf/model/TestSavedByTable.java
@@ -17,17 +17,15 @@
 
 package org.apache.poi.hwpf.model;
 
+import static org.apache.poi.hwpf.HWPFTestDataSamples.openSampleFile;
+import static org.apache.poi.hwpf.HWPFTestDataSamples.writeOutAndReadBack;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
-import java.io.InputStream;
 import java.util.Arrays;
 import java.util.List;
 
 import org.apache.poi.hwpf.HWPFDocument;
-import org.apache.poi.hwpf.HWPFTestDataSamples;
 import org.junit.jupiter.api.Test;
 
 /**
@@ -53,29 +51,21 @@ public final class TestSavedByTable {
      * Tests reading in the entries, comparing them against the expected
      * entries. Then tests writing the document out and reading the entries yet
      * again.
-     *
-     * @throws Exception if an unexpected error occurs.
      */
     @Test
     void testReadWrite() throws IOException {
         // This document is widely available on the internet as "blair.doc".
         // I tried stripping the content and saving the document but my version
         // of Word (from Office XP) strips this table out.
-        HWPFDocument doc = HWPFTestDataSamples.openSampleFile("saved-by-table.doc");
+        try (HWPFDocument doc = openSampleFile("saved-by-table.doc")) {
+            // Check what we just read.
+            assertEquals(expected, doc.getSavedByTable().getEntries(), "List of saved-by entries was not as expected");
 
-        // Check what we just read.
-        assertEquals( expected, doc.getSavedByTable().getEntries(), "List of saved-by entries was not as expected" );
-
-        // Now write the entire document out, and read it back in...
-        ByteArrayOutputStream byteStream = new ByteArrayOutputStream();
-        doc.write(byteStream);
-        InputStream copyStream = new ByteArrayInputStream(byteStream.toByteArray());
-        doc.close();
-        HWPFDocument copy = new HWPFDocument(copyStream);
-
-        // And check again.
-        assertEquals( expected, copy.getSavedByTable().getEntries(), "List of saved-by entries was incorrect after writing" );
-
-        copy.close();
+            // Now write the entire document out, and read it back in...
+            try (HWPFDocument copy = writeOutAndReadBack(doc)) {
+                // And check again.
+                assertEquals(expected, copy.getSavedByTable().getEntries(), "List of saved-by entries was incorrect after writing");
+            }
+        }
     }
 }
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hwpf/sprm/TestSprms.java b/poi-scratchpad/src/test/java/org/apache/poi/hwpf/sprm/TestSprms.java
index 65c5dac5a8..d8cbba82c8 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hwpf/sprm/TestSprms.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hwpf/sprm/TestSprms.java
@@ -19,43 +19,29 @@
 
 package org.apache.poi.hwpf.sprm;
 
+import static org.apache.poi.hwpf.HWPFTestDataSamples.openSampleFile;
+import static org.apache.poi.hwpf.HWPFTestDataSamples.writeOutAndReadBack;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
-import java.io.InputStream;
 import java.util.Locale;
 
-import org.apache.poi.POIDataSamples;
 import org.apache.poi.hwpf.HWPFDocument;
 import org.apache.poi.hwpf.usermodel.Paragraph;
 import org.apache.poi.hwpf.usermodel.Range;
 import org.junit.jupiter.api.Test;
 
 public class TestSprms {
-    private static HWPFDocument reload( HWPFDocument hwpfDocument )
-            throws IOException
-    {
-        ByteArrayOutputStream baos = new ByteArrayOutputStream();
-        hwpfDocument.write( baos );
-        return new HWPFDocument( new ByteArrayInputStream( baos.toByteArray() ) );
-    }
-
     /**
      * Test correct processing of "sprmPItap" (0x6649) and "sprmPFInTable"
      * (0x2416)
      */
     @Test
     void testInnerTable() throws Exception {
-        InputStream resourceAsStream = POIDataSamples.getDocumentInstance()
-                .openResourceAsStream( "innertable.doc" );
-        try (HWPFDocument hwpfDocument = new HWPFDocument( resourceAsStream )) {
-            resourceAsStream.close();
-
+        try (HWPFDocument hwpfDocument = openSampleFile("innertable.doc")) {
             testInnerTable(hwpfDocument);
-            try (HWPFDocument hwpfDocument2 = reload(hwpfDocument)) {
+            try (HWPFDocument hwpfDocument2 = writeOutAndReadBack(hwpfDocument)) {
                 testInnerTable(hwpfDocument2);
             }
         }
@@ -87,20 +73,12 @@ public class TestSprms {
      */
     @Test
     void testSprmPJc() throws IOException {
-        try (InputStream resourceAsStream = POIDataSamples.getDocumentInstance()
-                .openResourceAsStream( "Bug49820.doc" );
-        HWPFDocument hwpfDocument = new HWPFDocument( resourceAsStream )) {
-            resourceAsStream.close();
+        try (HWPFDocument hwpfDocument = openSampleFile( "Bug49820.doc" )) {
+            assertEquals(1, hwpfDocument.getStyleSheet().getParagraphStyle(8).getJustification());
 
-            assertEquals(1, hwpfDocument.getStyleSheet().getParagraphStyle(8)
-                    .getJustification());
-
-            try (HWPFDocument hwpfDocument2 = reload(hwpfDocument)) {
-
-                assertEquals(1, hwpfDocument2.getStyleSheet().getParagraphStyle(8)
-                        .getJustification());
+            try (HWPFDocument hwpfDocument2 = writeOutAndReadBack(hwpfDocument)) {
+                assertEquals(1, hwpfDocument2.getStyleSheet().getParagraphStyle(8).getJustification());
             }
         }
-
     }
 }
diff --git a/poi-scratchpad/src/test/java/org/apache/poi/hwpf/usermodel/TestHWPFWrite.java b/poi-scratchpad/src/test/java/org/apache/poi/hwpf/usermodel/TestHWPFWrite.java
index 3f0f8b7ce0..36ad393a51 100644
--- a/poi-scratchpad/src/test/java/org/apache/poi/hwpf/usermodel/TestHWPFWrite.java
+++ b/poi-scratchpad/src/test/java/org/apache/poi/hwpf/usermodel/TestHWPFWrite.java
@@ -20,14 +20,13 @@ package org.apache.poi.hwpf.usermodel;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.POIDataSamples;
 import org.apache.poi.hwpf.HWPFDocument;
 import org.apache.poi.hwpf.HWPFTestCase;
@@ -48,20 +47,17 @@ public final class TestHWPFWrite extends HWPFTestCase {
      */
     @Test
     void testWriteStream() throws IOException {
-        HWPFDocument doc = HWPFTestDataSamples.openSampleFile("SampleDoc.doc");
-
-        Range r = doc.getRange();
-        assertEquals("I am a test document\r", r.getParagraph(0).text());
-
-        ByteArrayOutputStream baos = new ByteArrayOutputStream();
-        doc.write(baos);
-        doc.close();
-        ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
+        UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
+        try (HWPFDocument doc = HWPFTestDataSamples.openSampleFile("SampleDoc.doc")) {
+            Range r = doc.getRange();
+            assertEquals("I am a test document\r", r.getParagraph(0).text());
+            doc.write(baos);
+        }
 
-        doc = new HWPFDocument(bais);
-        r = doc.getRange();
-        assertEquals("I am a test document\r", r.getParagraph(0).text());
-        doc.close();
+        try (HWPFDocument doc = new HWPFDocument(baos.toInputStream())) {
+            Range r = doc.getRange();
+            assertEquals("I am a test document\r", r.getParagraph(0).text());
+        }
     }
 
     /**
diff --git a/poi/build.gradle b/poi/build.gradle
index d4388eebfc..23d024c516 100644
--- a/poi/build.gradle
+++ b/poi/build.gradle
@@ -39,6 +39,7 @@ dependencies {
     api "commons-codec:commons-codec:${commonsCodecVersion}"
     api 'org.apache.commons:commons-collections4:4.4'
     api "org.apache.commons:commons-math3:${commonsMathVersion}"
+    api "commons-io:commons-io:${commonsIoVersion}"
     api 'com.zaxxer:SparseBitSet:1.2'
     implementation "org.apache.logging.log4j:log4j-api:${log4jVersion}"
     implementation 'javax.activation:activation:1.1.1'
diff --git a/poi/src/main/java/org/apache/poi/POIDocument.java b/poi/src/main/java/org/apache/poi/POIDocument.java
index e2f613af64..e1405f9977 100644
--- a/poi/src/main/java/org/apache/poi/POIDocument.java
+++ b/poi/src/main/java/org/apache/poi/POIDocument.java
@@ -21,8 +21,6 @@ import static org.apache.logging.log4j.util.Unbox.box;
 import static org.apache.poi.hpsf.PropertySetFactory.newDocumentSummaryInformation;
 
 import java.io.BufferedOutputStream;
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.Closeable;
 import java.io.File;
 import java.io.FileOutputStream;
@@ -32,6 +30,7 @@ import java.io.OutputStream;
 import java.security.GeneralSecurityException;
 import java.util.List;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.poi.hpsf.DocumentSummaryInformation;
@@ -323,18 +322,16 @@ public abstract class POIDocument implements Closeable {
      *      {@link POIFSFileSystem} occurs
      */
     private void writePropertySet(String name, PropertySet set, POIFSFileSystem outFS) throws IOException {
-        try {
+        try (UnsynchronizedByteArrayOutputStream bOut = new UnsynchronizedByteArrayOutputStream()) {
             PropertySet mSet = new PropertySet(set);
-            ByteArrayOutputStream bOut = new ByteArrayOutputStream();
-
             mSet.write(bOut);
-            byte[] data = bOut.toByteArray();
-            ByteArrayInputStream bIn = new ByteArrayInputStream(data);
 
-            // Create or Update the Property Set stream in the POIFS
-            outFS.createOrUpdateDocument(bIn, name);
+            try (InputStream bIn = bOut.toInputStream()) {
+                // Create or Update the Property Set stream in the POIFS
+                outFS.createOrUpdateDocument(bIn, name);
+            }
 
-            LOG.atInfo().log("Wrote property set {} of size {}", name, box(data.length));
+            LOG.atInfo().log("Wrote property set {} of size {}", name, box(bOut.size()));
         } catch(WritingNotSupportedException ignored) {
             LOG.atError().log("Couldn't write property set with name {} as not supported by HPSF yet", name);
         }
diff --git a/poi/src/main/java/org/apache/poi/ddf/DefaultEscherRecordFactory.java b/poi/src/main/java/org/apache/poi/ddf/DefaultEscherRecordFactory.java
index 249e74cb2e..e7f02f471b 100644
--- a/poi/src/main/java/org/apache/poi/ddf/DefaultEscherRecordFactory.java
+++ b/poi/src/main/java/org/apache/poi/ddf/DefaultEscherRecordFactory.java
@@ -22,7 +22,6 @@ import java.util.function.Supplier;
 import org.apache.poi.util.BitField;
 import org.apache.poi.util.BitFieldFactory;
 import org.apache.poi.util.LittleEndian;
-import org.apache.poi.util.Removal;
 
 /**
  * Generates escher records when provided the byte array containing those records.
@@ -73,23 +72,4 @@ public class DefaultEscherRecordFactory implements EscherRecordFactory {
         // catch all
         return UnknownEscherRecord::new;
     }
-
-
-    /**
-     * @deprecated this method is not used anymore to identify container records
-     */
-    @Deprecated
-    @Removal(version = "5.0.0")
-    public static boolean isContainer(short options, short recordId){
-        if(recordId >= EscherContainerRecord.DGG_CONTAINER &&  recordId
-                <= EscherContainerRecord.SOLVER_CONTAINER){
-            return true;
-        } else {
-            if (recordId == EscherTextboxRecord.RECORD_ID) {
-                return false;
-            } else {
-                return ( options & (short) 0x000F ) == (short) 0x000F;
-            }
-        }
-    }
 }
diff --git a/poi/src/main/java/org/apache/poi/ddf/EscherMetafileBlip.java b/poi/src/main/java/org/apache/poi/ddf/EscherMetafileBlip.java
index 6713b5fc17..75062a7005 100644
--- a/poi/src/main/java/org/apache/poi/ddf/EscherMetafileBlip.java
+++ b/poi/src/main/java/org/apache/poi/ddf/EscherMetafileBlip.java
@@ -17,10 +17,11 @@
 
 package org.apache.poi.ddf;
 
+import static org.apache.logging.log4j.util.Unbox.box;
+
 import java.awt.Dimension;
 import java.awt.Rectangle;
 import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.util.Collections;
 import java.util.LinkedHashMap;
@@ -29,21 +30,30 @@ import java.util.function.Supplier;
 import java.util.zip.DeflaterOutputStream;
 import java.util.zip.InflaterInputStream;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.poi.hssf.usermodel.HSSFPictureData;
 import org.apache.poi.util.IOUtils;
 import org.apache.poi.util.LittleEndian;
-
-import static org.apache.logging.log4j.util.Unbox.box;
+import org.apache.poi.util.Removal;
 
 public final class EscherMetafileBlip extends EscherBlipRecord {
     private static final Logger LOGGER = LogManager.getLogger(EscherMetafileBlip.class);
     //arbitrarily selected; may need to increase
     private static final int MAX_RECORD_LENGTH = 100_000_000;
 
+    /** @deprecated use EscherRecordTypes.BLIP_EMF.typeID */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short RECORD_ID_EMF = EscherRecordTypes.BLIP_EMF.typeID;
+    /** @deprecated use EscherRecordTypes.BLIP_WMF.typeID */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short RECORD_ID_WMF = EscherRecordTypes.BLIP_WMF.typeID;
+    /** @deprecated use EscherRecordTypes.BLIP_PICT.typeID */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short RECORD_ID_PICT = EscherRecordTypes.BLIP_PICT.typeID;
 
     private static final int HEADER_SIZE = 8;
@@ -150,9 +160,10 @@ public final class EscherMetafileBlip extends EscherBlipRecord {
         data[pos] = field_6_fCompression; pos++;
         data[pos] = field_7_fFilter; pos++;
 
-        System.arraycopy( raw_pictureData, 0, data, pos, raw_pictureData.length ); pos += raw_pictureData.length;
+        System.arraycopy( raw_pictureData, 0, data, pos, raw_pictureData.length );
+        pos += raw_pictureData.length;
         if(remainingData != null) {
-            System.arraycopy( remainingData, 0, data, pos, remainingData.length ); pos += remainingData.length;
+            System.arraycopy( remainingData, 0, data, pos, remainingData.length );
         }
 
         listener.afterRecordSerialize(offset + getRecordSize(), getRecordId(), getRecordSize(), this);
@@ -166,15 +177,9 @@ public final class EscherMetafileBlip extends EscherBlipRecord {
      * @return the inflated picture data.
      */
     private static byte[] inflatePictureData(byte[] data) {
-        try {
-            InflaterInputStream in = new InflaterInputStream(
-                new ByteArrayInputStream( data ) );
-            ByteArrayOutputStream out = new ByteArrayOutputStream();
-            byte[] buf = new byte[4096];
-            int readBytes;
-            while ((readBytes = in.read(buf)) > 0) {
-                out.write(buf, 0, readBytes);
-            }
+        try (InflaterInputStream in = new InflaterInputStream(new ByteArrayInputStream(data));
+             UnsynchronizedByteArrayOutputStream out = new UnsynchronizedByteArrayOutputStream()) {
+            IOUtils.copy(in, out);
             return out.toByteArray();
         } catch (IOException e) {
             LOGGER.atWarn().withThrowable(e).log("Possibly corrupt compression or non-compressed data");
@@ -390,11 +395,10 @@ public final class EscherMetafileBlip extends EscherBlipRecord {
         // "... LZ compression algorithm in the format used by GNU Zip deflate/inflate with a 32k window ..."
         // not sure what to do, when lookup tables exceed 32k ...
 
-        try {
-	        ByteArrayOutputStream bos = new ByteArrayOutputStream();
-	        DeflaterOutputStream dos = new DeflaterOutputStream(bos);
-	        dos.write(pictureData);
-	        dos.close();
+        try (UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream()) {
+	        try (DeflaterOutputStream dos = new DeflaterOutputStream(bos)) {
+                dos.write(pictureData);
+            }
 	        raw_pictureData = bos.toByteArray();
         } catch (IOException e) {
         	throw new RuntimeException("Can't compress metafile picture data", e);
diff --git a/poi/src/main/java/org/apache/poi/hpsf/HPSFPropertiesOnlyDocument.java b/poi/src/main/java/org/apache/poi/hpsf/HPSFPropertiesOnlyDocument.java
index a0a5d68fb8..b5fffd5d84 100644
--- a/poi/src/main/java/org/apache/poi/hpsf/HPSFPropertiesOnlyDocument.java
+++ b/poi/src/main/java/org/apache/poi/hpsf/HPSFPropertiesOnlyDocument.java
@@ -41,16 +41,18 @@ public class HPSFPropertiesOnlyDocument extends POIDocument {
     /**
      * Write out to the currently open file the properties changes, but nothing else
      */
+    @Override
     public void write() throws IOException {
         POIFSFileSystem fs = getDirectory().getFileSystem();
-        
-        validateInPlaceWritePossible();        
+
+        validateInPlaceWritePossible();
         writeProperties(fs, null);
         fs.writeFilesystem();
     }
     /**
      * Write out, with any properties changes, but nothing else
      */
+    @Override
     public void write(File newFile) throws IOException {
         try (POIFSFileSystem fs = POIFSFileSystem.create(newFile)) {
             write(fs);
@@ -60,25 +62,26 @@ public class HPSFPropertiesOnlyDocument extends POIDocument {
     /**
      * Write out, with any properties changes, but nothing else
      */
+    @Override
     public void write(OutputStream out) throws IOException {
         try (POIFSFileSystem fs = new POIFSFileSystem()) {
             write(fs);
             fs.writeFilesystem(out);
         }
     }
-    
+
     private void write(POIFSFileSystem fs) throws IOException {
         // For tracking what we've written out, so far
         List<String> excepts = new ArrayList<>(2);
 
         // Write out our HPFS properties, with any changes
         writeProperties(fs, excepts);
-        
+
         // Copy over everything else unchanged
         FilteringDirectoryNode src = new FilteringDirectoryNode(getDirectory(), excepts);
         FilteringDirectoryNode dest = new FilteringDirectoryNode(fs.getRoot(), excepts);
         EntryUtils.copyNodes(src, dest);
-        
+
         // Caller will save the resultant POIFSFileSystem to the stream/file
     }
 }
diff --git a/poi/src/main/java/org/apache/poi/hpsf/MarkUnsupportedException.java b/poi/src/main/java/org/apache/poi/hpsf/MarkUnsupportedException.java
deleted file mode 100644
index 450c892abc..0000000000
--- a/poi/src/main/java/org/apache/poi/hpsf/MarkUnsupportedException.java
+++ /dev/null
@@ -1,69 +0,0 @@
-/* ====================================================================
-   Licensed to the Apache Software Foundation (ASF) under one or more
-   contributor license agreements.  See the NOTICE file distributed with
-   this work for additional information regarding copyright ownership.
-   The ASF licenses this file to You under the Apache License, Version 2.0
-   (the "License"); you may not use this file except in compliance with
-   the License.  You may obtain a copy of the License at
-
-       http://www.apache.org/licenses/LICENSE-2.0
-
-   Unless required by applicable law or agreed to in writing, software
-   distributed under the License is distributed on an "AS IS" BASIS,
-   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-   See the License for the specific language governing permissions and
-   limitations under the License.
-==================================================================== */
-
-package org.apache.poi.hpsf;
-
-/**
- * <p>This exception is thrown if an {@link java.io.InputStream} does
- * not support the {@link java.io.InputStream#mark} operation.</p>
- */
-public class MarkUnsupportedException extends HPSFException
-{
-
-    /**
-     * <p>Constructor</p>
-     */
-    public MarkUnsupportedException()
-    {
-        super();
-    }
-
-
-    /**
-     * <p>Constructor</p>
-     *
-     * @param msg The exception's message string
-     */
-    public MarkUnsupportedException(final String msg)
-    {
-        super(msg);
-    }
-
-
-    /**
-     * <p>Constructor</p>
-     *
-     * @param reason This exception's underlying reason
-     */
-    public MarkUnsupportedException(final Throwable reason)
-    {
-        super(reason);
-    }
-
-
-   /**
-    * <p>Constructor</p>
-    *
-    * @param msg The exception's message string
-    * @param reason This exception's underlying reason
-    */
-    public MarkUnsupportedException(final String msg, final Throwable reason)
-    {
-        super(msg, reason);
-    }
-
-}
diff --git a/poi/src/main/java/org/apache/poi/hpsf/Property.java b/poi/src/main/java/org/apache/poi/hpsf/Property.java
index 0e3e2cdea2..2b05f763af 100644
--- a/poi/src/main/java/org/apache/poi/hpsf/Property.java
+++ b/poi/src/main/java/org/apache/poi/hpsf/Property.java
@@ -17,7 +17,8 @@
 
 package org.apache.poi.hpsf;
 
-import java.io.ByteArrayOutputStream;
+import static org.apache.logging.log4j.util.Unbox.box;
+
 import java.io.IOException;
 import java.io.OutputStream;
 import java.io.UnsupportedEncodingException;
@@ -29,6 +30,7 @@ import java.util.Locale;
 import java.util.Objects;
 import java.util.concurrent.TimeUnit;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.poi.hpsf.wellknown.PropertyIDMap;
@@ -39,8 +41,6 @@ import org.apache.poi.util.LittleEndianByteArrayInputStream;
 import org.apache.poi.util.LittleEndianConsts;
 import org.apache.poi.util.LocaleUtil;
 
-import static org.apache.logging.log4j.util.Unbox.box;
-
 /**
  * A property in a {@link Section} of a {@link PropertySet}.<p>
  *
@@ -115,7 +115,7 @@ public class Property {
     }
 
     /**
-     * Creates a {@link Property} instance by reading its bytes
+     * Creates a Property instance by reading its bytes
      * from the property set stream.
      *
      * @param id The property's ID.
@@ -153,7 +153,7 @@ public class Property {
     }
 
     /**
-     * Creates a {@link Property} instance by reading its bytes
+     * Creates a Property instance by reading its bytes
      * from the property set stream.
      *
      * @param id The property's ID.
@@ -272,7 +272,7 @@ public class Property {
 
         /* Variable length: */
         if (type == Variant.VT_LPSTR || type == Variant.VT_LPWSTR) {
-            ByteArrayOutputStream bos = new ByteArrayOutputStream();
+            UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream();
             try {
                 length = write(bos, property) - 2*LittleEndianConsts.INT_SIZE;
                 /* Pad to multiples of 4. */
@@ -295,8 +295,6 @@ public class Property {
      * ID == 0 is a special case: It does not have a type, and its value is the
      * section's dictionary. Another special case are strings: Two properties
      * may have the different types Variant.VT_LPSTR and Variant.VT_LPWSTR;
-     *
-     * @see Object#equals(Object)
      */
     @Override
     public boolean equals(final Object o) {
@@ -366,22 +364,12 @@ public class Property {
             (t2 == Variant.VT_LPSTR && t1 == Variant.VT_LPWSTR));
     }
 
-
-
-    /**
-     * @see Object#hashCode()
-     */
     @Override
     public int hashCode() {
         return Objects.hash(id,type,value);
 
     }
 
-
-
-    /**
-     * @see Object#toString()
-     */
     @Override
     public String toString() {
         return toString(Property.DEFAULT_CODEPAGE, null);
@@ -411,7 +399,7 @@ public class Property {
         if (value instanceof String) {
             b.append((String)value);
             b.append("\n");
-            ByteArrayOutputStream bos = new ByteArrayOutputStream();
+            UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream();
             try {
                 write(bos, codepage);
             } catch (Exception e) {
diff --git a/poi/src/main/java/org/apache/poi/hpsf/PropertySet.java b/poi/src/main/java/org/apache/poi/hpsf/PropertySet.java
index d110747d11..324fb4b4c9 100644
--- a/poi/src/main/java/org/apache/poi/hpsf/PropertySet.java
+++ b/poi/src/main/java/org/apache/poi/hpsf/PropertySet.java
@@ -18,7 +18,6 @@
 package org.apache.poi.hpsf;
 
 import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
@@ -27,6 +26,7 @@ import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.EmptyFileException;
 import org.apache.poi.hpsf.wellknown.PropertyIDMap;
 import org.apache.poi.poifs.filesystem.DirectoryEntry;
@@ -38,7 +38,6 @@ import org.apache.poi.util.LittleEndianByteArrayInputStream;
 import org.apache.poi.util.LittleEndianConsts;
 import org.apache.poi.util.LittleEndianOutputStream;
 import org.apache.poi.util.NotImplemented;
-import org.apache.poi.util.Removal;
 
 /**
  * Represents a property set in the Horrible Property Set Format
@@ -166,7 +165,7 @@ public class PropertySet {
 
 
     /**
-     * Creates a {@link PropertySet} instance from an {@link
+     * Creates a PropertySet instance from an {@link
      * InputStream} in the Horrible Property Set Format.<p>
      *
      * The constructor reads the first few bytes from the stream
@@ -198,7 +197,7 @@ public class PropertySet {
 
 
     /**
-     * Creates a {@link PropertySet} instance from a byte array that
+     * Creates a PropertySet instance from a byte array that
      * represents a stream in the Horrible Property Set Format.
      *
      * @param stream The byte array holding the stream data.
@@ -220,7 +219,7 @@ public class PropertySet {
     }
 
     /**
-     * Creates a {@link PropertySet} instance from a byte array
+     * Creates a PropertySet instance from a byte array
      * that represents a stream in the Horrible Property Set Format.
      *
      * @param stream The byte array holding the stream data. The
@@ -439,7 +438,7 @@ public class PropertySet {
 
 
     /**
-     * Initializes this {@link PropertySet} instance from a byte
+     * Initializes this PropertySet instance from a byte
      * array. The method assumes that it has been checked already that
      * the byte array indeed represents a property set stream. It does
      * no more checks on its own.
@@ -515,7 +514,7 @@ public class PropertySet {
     }
 
     private byte[] toBytes() throws WritingNotSupportedException, IOException {
-        ByteArrayOutputStream bos = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream();
         LittleEndianOutputStream leos = new LittleEndianOutputStream(bos);
 
         /* Write the number of sections in this property set stream. */
@@ -590,7 +589,7 @@ public class PropertySet {
      * document. The input stream represents a snapshot of the property set.
      * If the latter is modified while the input stream is still being
      * read, the modifications will not be reflected in the input stream but in
-     * the {@link PropertySet} only.
+     * the PropertySet only.
      *
      * @return the contents of this property set stream
      *
@@ -657,9 +656,9 @@ public class PropertySet {
     }
 
     /**
-     * Checks whether this {@link PropertySet} represents a Summary Information.
+     * Checks whether this PropertySet represents a Summary Information.
      *
-     * @return {@code true} if this {@link PropertySet}
+     * @return {@code true} if this PropertySet
      * represents a Summary Information, else {@code false}.
      */
     public boolean isSummaryInformation() {
@@ -667,9 +666,9 @@ public class PropertySet {
     }
 
     /**
-     * Checks whether this {@link PropertySet} is a Document Summary Information.
+     * Checks whether this PropertySet is a Document Summary Information.
      *
-     * @return {@code true} if this {@link PropertySet}
+     * @return {@code true} if this PropertySet
      * represents a Document Summary Information, else {@code false}.
      */
     public boolean isDocumentSummaryInformation() {
@@ -687,13 +686,13 @@ public class PropertySet {
 
     /**
      * Convenience method returning the {@link Property} array contained in this
-     * property set. It is a shortcut for getting he {@link PropertySet}'s
+     * property set. It is a shortcut for getting he PropertySets
      * {@link Section}s list and then getting the {@link Property} array from the
      * first {@link Section}.
      *
      * @return The properties of the only {@link Section} of this
-     * {@link PropertySet}.
-     * @throws NoSingleSectionException if the {@link PropertySet} has
+     * PropertySet.
+     * @throws NoSingleSectionException if the PropertySet has
      * more or less than one {@link Section}.
      */
     public Property[] getProperties() throws NoSingleSectionException {
@@ -709,7 +708,7 @@ public class PropertySet {
      *
      * @param id The property ID
      * @return The property value
-     * @throws NoSingleSectionException if the {@link PropertySet} has
+     * @throws NoSingleSectionException if the PropertySet has
      * more or less than one {@link Section}.
      */
     protected Object getProperty(final int id) throws NoSingleSectionException {
@@ -726,7 +725,7 @@ public class PropertySet {
      *
      * @param id The property ID
      * @return The property value
-     * @throws NoSingleSectionException if the {@link PropertySet} has
+     * @throws NoSingleSectionException if the PropertySet has
      * more or less than one {@link Section}.
      */
     boolean getPropertyBooleanValue(final int id) throws NoSingleSectionException {
@@ -744,7 +743,7 @@ public class PropertySet {
      *
      * @param id The property ID
      * @return The propertyIntValue value
-     * @throws NoSingleSectionException if the {@link PropertySet} has
+     * @throws NoSingleSectionException if the PropertySet has
      * more or less than one {@link Section}.
      */
     int getPropertyIntValue(final int id) throws NoSingleSectionException {
@@ -765,7 +764,7 @@ public class PropertySet {
      * @return {@code true} if the last call to {@link
      * #getPropertyIntValue} or {@link #getProperty} tried to access a
      * property that was not available, else {@code false}.
-     * @throws NoSingleSectionException if the {@link PropertySet} has
+     * @throws NoSingleSectionException if the PropertySet has
      * more than one {@link Section}.
      */
     public boolean wasNull() throws NoSingleSectionException {
@@ -775,9 +774,9 @@ public class PropertySet {
 
 
     /**
-     * Gets the {@link PropertySet}'s first section.
+     * Gets the PropertySets first section.
      *
-     * @return The {@link PropertySet}'s first section.
+     * @return The PropertySets first section.
      */
     @SuppressWarnings("WeakerAccess")
     public Section getFirstSection() {
@@ -825,22 +824,12 @@ public class PropertySet {
         return getSections().containsAll(ps.getSections());
     }
 
-
-
-    /**
-     * @see Object#hashCode()
-     */
     @NotImplemented
     @Override
     public int hashCode() {
         throw new UnsupportedOperationException("FIXME: Not yet implemented.");
     }
 
-
-
-    /**
-     * @see Object#toString()
-     */
     @Override
     public String toString() {
         final StringBuilder b = new StringBuilder();
@@ -888,7 +877,7 @@ public class PropertySet {
         getFirstSection().setProperty((int)id, value);
     }
 
-    private static void putClassId(final ByteArrayOutputStream out, final ClassID n) {
+    private static void putClassId(final UnsynchronizedByteArrayOutputStream out, final ClassID n) {
         byte[] b = new byte[16];
         n.write(b, 0);
         out.write(b, 0, b.length);
diff --git a/poi/src/main/java/org/apache/poi/hpsf/PropertySetFactory.java b/poi/src/main/java/org/apache/poi/hpsf/PropertySetFactory.java
index d5e0c5c0c2..ec2b8bc9dd 100644
--- a/poi/src/main/java/org/apache/poi/hpsf/PropertySetFactory.java
+++ b/poi/src/main/java/org/apache/poi/hpsf/PropertySetFactory.java
@@ -54,8 +54,6 @@ public class PropertySetFactory {
     throws FileNotFoundException, NoPropertySetStreamException, IOException, UnsupportedEncodingException {
         try (DocumentInputStream inp = ((DirectoryNode)dir).createDocumentInputStream(name)) {
             return create(inp);
-        } catch (MarkUnsupportedException e) {
-            return null;
         }
     }
 
@@ -71,14 +69,12 @@ public class PropertySetFactory {
      * @return The created {@link PropertySet}.
      * @throws NoPropertySetStreamException if the stream does not
      * contain a property set.
-     * @throws MarkUnsupportedException if the stream does not support
-     * the {@code mark} operation.
      * @throws IOException if some I/O problem occurs.
      * @exception UnsupportedEncodingException if the specified codepage is not
      * supported.
      */
     public static PropertySet create(final InputStream stream)
-    throws NoPropertySetStreamException, MarkUnsupportedException, UnsupportedEncodingException, IOException {
+    throws NoPropertySetStreamException, IOException {
         stream.mark(PropertySet.OFFSET_HEADER+ClassID.LENGTH+1);
         LittleEndianInputStream leis = new LittleEndianInputStream(stream);
         int byteOrder =  leis.readUShort();
diff --git a/poi/src/main/java/org/apache/poi/hpsf/Section.java b/poi/src/main/java/org/apache/poi/hpsf/Section.java
index c404e49858..90d20cf448 100644
--- a/poi/src/main/java/org/apache/poi/hpsf/Section.java
+++ b/poi/src/main/java/org/apache/poi/hpsf/Section.java
@@ -17,7 +17,6 @@
 
 package org.apache.poi.hpsf;
 
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.OutputStream;
 import java.io.UnsupportedEncodingException;
@@ -31,6 +30,7 @@ import java.util.Set;
 import java.util.TreeMap;
 
 import org.apache.commons.collections4.bidimap.TreeBidiMap;
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.poi.hpsf.wellknown.PropertyIDMap;
@@ -66,7 +66,7 @@ public class Section {
      * established when the section's size is calculated and can be reused
      * later. If the array is empty, the section was modified and the bytes need to be regenerated.
      */
-    private final ByteArrayOutputStream sectionBytes = new ByteArrayOutputStream();
+    private final UnsynchronizedByteArrayOutputStream sectionBytes = new UnsynchronizedByteArrayOutputStream();
 
     /**
      * The offset of the section in the stream.
@@ -86,7 +86,7 @@ public class Section {
     private transient boolean wasNull;
 
     /**
-     * Creates an empty {@link Section}.
+     * Creates an empty Section.
      */
     public Section() {
         this._offset = -1;
@@ -112,7 +112,7 @@ public class Section {
 
 
     /**
-     * Creates a {@link Section} instance from a byte array.
+     * Creates a Section instance from a byte array.
      *
      * @param src Contains the complete property set stream.
      * @param offset The position in the stream that points to the
@@ -428,7 +428,6 @@ public class Section {
      * @see #getProperty
      * @see Variant
      */
-    @SuppressWarnings("deprecation")
     public void setProperty(final int id, final long variantType, final Object value) {
         setProperty(new Property(id, variantType, value));
     }
@@ -601,7 +600,7 @@ public class Section {
 
     /**
      * Returns the PID string associated with a property ID. The ID
-     * is first looked up in the {@link Section Sections} private dictionary.
+     * is first looked up in the Sections private dictionary.
      * If it is not found there, the property PID string is taken
      * from sections format IDs namespace.
      * If the PID is also undefined there, i.e. it is not well-known,
@@ -641,14 +640,14 @@ public class Section {
      *
      * <ul>
      *
-     * <li>The other object is not a {@link Section}.
+     * <li>The other object is not a Section.
      *
      * <li>The format IDs of the two sections are not equal.
      *
      * <li>The sections have a different number of properties. However,
      * properties with ID 1 (codepage) are not counted.
      *
-     * <li>The other object is not a {@link Section}.
+     * <li>The other object is not a Section.
      *
      * <li>The properties have different values. The order of the properties
      * is irrelevant.
@@ -736,7 +735,7 @@ public class Section {
         }
 
         final int[][] offsets = new int[properties.size()][2];
-        final ByteArrayOutputStream bos = new ByteArrayOutputStream();
+        final UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream();
         final LittleEndianOutputStream leos = new LittleEndianOutputStream(bos);
 
         /* Write the section's length - dummy value, fixed later */
@@ -932,19 +931,11 @@ public class Section {
         }
     }
 
-
-
-    /**
-     * @see Object#hashCode()
-     */
     @Override
     public int hashCode() {
         return Arrays.deepHashCode(new Object[]{getFormatID(),getProperties()});
     }
 
-    /**
-     * @see Object#toString()
-     */
     @Override
     public String toString() {
         return toString(null);
@@ -1008,7 +999,7 @@ public class Section {
      */
     public int getCodepage() {
         final Integer codepage = (Integer) getProperty(PropertyIDMap.PID_CODEPAGE);
-        return (codepage == null) ? -1 : codepage.intValue();
+        return (codepage == null) ? -1 : codepage;
     }
 
     /**
diff --git a/poi/src/main/java/org/apache/poi/hpsf/SummaryInformation.java b/poi/src/main/java/org/apache/poi/hpsf/SummaryInformation.java
index 4c85b8fda8..564146a94a 100644
--- a/poi/src/main/java/org/apache/poi/hpsf/SummaryInformation.java
+++ b/poi/src/main/java/org/apache/poi/hpsf/SummaryInformation.java
@@ -50,14 +50,14 @@ public final class SummaryInformation extends PropertySet {
     }
 
     /**
-     * Creates an empty {@link SummaryInformation}.
+     * Creates an empty SummaryInformation.
      */
     public SummaryInformation() {
         getFirstSection().setFormatID(FORMAT_ID);
     }
 
     /**
-     * Creates a {@link SummaryInformation} from a given {@link
+     * Creates a SummaryInformation from a given {@link
      * PropertySet}.
      *
      * @param ps A property set which should be created from a summary
@@ -73,7 +73,7 @@ public final class SummaryInformation extends PropertySet {
     }
 
     /**
-     * Creates a {@link SummaryInformation} instance from an {@link
+     * Creates a SummaryInformation instance from an {@link
      * InputStream} in the Horrible Property Set Format.<p>
      *
      * The constructor reads the first few bytes from the stream
@@ -85,8 +85,6 @@ public final class SummaryInformation extends PropertySet {
      *
      * @param stream Holds the data making out the property set
      * stream.
-     * @throws MarkUnsupportedException
-     *    if the stream does not support the {@link InputStream#markSupported} method.
      * @throws IOException
      *    if the {@link InputStream} cannot be accessed as needed.
      * @exception NoPropertySetStreamException
@@ -95,7 +93,7 @@ public final class SummaryInformation extends PropertySet {
      *    if a character encoding is not supported.
      */
     public SummaryInformation(final InputStream stream)
-    throws NoPropertySetStreamException, MarkUnsupportedException, IOException, UnsupportedEncodingException {
+    throws NoPropertySetStreamException, IOException {
         super(stream);
     }
 
@@ -481,10 +479,10 @@ public final class SummaryInformation extends PropertySet {
 
 
     /**
-     * Returns the page count or 0 if the {@link SummaryInformation} does
+     * Returns the page count or 0 if the SummaryInformation does
      * not contain a page count.
      *
-     * @return The page count or 0 if the {@link SummaryInformation} does not
+     * @return The page count or 0 if the SummaryInformation does not
      *         contain a page count.
      */
     public int getPageCount() {
@@ -514,7 +512,7 @@ public final class SummaryInformation extends PropertySet {
 
 
     /**
-     * Returns the word count or 0 if the {@link SummaryInformation} does
+     * Returns the word count or 0 if the SummaryInformation does
      * not contain a word count.
      *
      * @return The word count or {@code null}
@@ -546,7 +544,7 @@ public final class SummaryInformation extends PropertySet {
 
 
     /**
-     * Returns the character count or 0 if the {@link SummaryInformation}
+     * Returns the character count or 0 if the SummaryInformation
      * does not contain a char count.
      *
      * @return The character count or {@code null}
@@ -665,7 +663,7 @@ public final class SummaryInformation extends PropertySet {
      *
      * <ul>
      *
-     * <li>0 if the {@link SummaryInformation} does not contain a
+     * <li>0 if the SummaryInformation does not contain a
      * security field or if there is no security on the document. Use
      * {@link PropertySet#wasNull()} to distinguish between the two
      * cases!
diff --git a/poi/src/main/java/org/apache/poi/hssf/dev/ReSave.java b/poi/src/main/java/org/apache/poi/hssf/dev/ReSave.java
index 2f31eb48d8..2254ed58fe 100644
--- a/poi/src/main/java/org/apache/poi/hssf/dev/ReSave.java
+++ b/poi/src/main/java/org/apache/poi/hssf/dev/ReSave.java
@@ -17,11 +17,11 @@
 
 package org.apache.poi.hssf.dev;
 
-import java.io.ByteArrayOutputStream;
 import java.io.FileInputStream;
 import java.io.FileOutputStream;
 import java.io.OutputStream;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.hssf.usermodel.HSSFSheet;
 import org.apache.poi.hssf.usermodel.HSSFWorkbook;
 
@@ -60,7 +60,7 @@ public class ReSave {
                         System.out.print("saving to " + outputFile + "...");
                     }
 
-                    try (OutputStream os = saveToMemory ? new ByteArrayOutputStream() : new FileOutputStream(outputFile)) {
+                    try (OutputStream os = saveToMemory ? new UnsynchronizedByteArrayOutputStream() : new FileOutputStream(outputFile)) {
                         wb.write(os);
                     }
                     System.out.println("done");
diff --git a/poi/src/main/java/org/apache/poi/hssf/record/EscherAggregate.java b/poi/src/main/java/org/apache/poi/hssf/record/EscherAggregate.java
index ac6bc6bf5c..8a1925e102 100644
--- a/poi/src/main/java/org/apache/poi/hssf/record/EscherAggregate.java
+++ b/poi/src/main/java/org/apache/poi/hssf/record/EscherAggregate.java
@@ -19,7 +19,6 @@ package org.apache.poi.hssf.record;
 
 import static org.apache.poi.hssf.record.RecordInputStream.MAX_RECORD_DATA_SIZE;
 
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -31,6 +30,7 @@ import java.util.List;
 import java.util.Map;
 import java.util.function.Supplier;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.ddf.DefaultEscherRecordFactory;
 import org.apache.poi.ddf.EscherClientDataRecord;
 import org.apache.poi.ddf.EscherContainerRecord;
@@ -40,9 +40,11 @@ import org.apache.poi.ddf.EscherSerializationListener;
 import org.apache.poi.ddf.EscherSpRecord;
 import org.apache.poi.ddf.EscherSpgrRecord;
 import org.apache.poi.ddf.EscherTextboxRecord;
+import org.apache.poi.sl.usermodel.ShapeType;
 import org.apache.poi.util.GenericRecordXmlWriter;
 import org.apache.poi.util.IOUtils;
 import org.apache.poi.util.RecordFormatException;
+import org.apache.poi.util.Removal;
 
 /**
  * This class is used to aggregate the MSODRAWING and OBJ record
@@ -93,210 +95,825 @@ public final class EscherAggregate extends AbstractEscherHolderRecord {
     private static final int MAX_RECORD_LENGTH = 100_000_000;
 
 
+    /** @deprecated not used */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_MIN = (short) 0;
-    public static final short ST_NOT_PRIMATIVE = ST_MIN;
+    /** @deprecated use {@link ShapeType#NOT_PRIMITIVE} */
+    @Deprecated
+    @Removal(version = "5.3")
+    public static final short ST_NOT_PRIMATIVE = (short) 0;
+    /** @deprecated use {@link ShapeType#RECT} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_RECTANGLE = (short) 1;
+    /** @deprecated use {@link ShapeType#ROUND_RECT} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_ROUNDRECTANGLE = (short) 2;
+    /** @deprecated use {@link ShapeType#ELLIPSE} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_ELLIPSE = (short) 3;
+    /** @deprecated use {@link ShapeType#DIAMOND} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_DIAMOND = (short) 4;
+    /** @deprecated use {@link ShapeType#TRIANGLE} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_ISOCELESTRIANGLE = (short) 5;
+    /** @deprecated use {@link ShapeType#RT_TRIANGLE} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_RIGHTTRIANGLE = (short) 6;
+    /** @deprecated use {@link ShapeType#PARALLELOGRAM} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_PARALLELOGRAM = (short) 7;
+    /** @deprecated use {@link ShapeType#TRAPEZOID} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_TRAPEZOID = (short) 8;
+    /** @deprecated use {@link ShapeType#HEXAGON} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_HEXAGON = (short) 9;
+    /** @deprecated use {@link ShapeType#OCTAGON} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_OCTAGON = (short) 10;
+    /** @deprecated use {@link ShapeType#PLUS} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_PLUS = (short) 11;
+    /** @deprecated use {@link ShapeType#STAR_5} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_STAR = (short) 12;
+    /** @deprecated use {@link ShapeType#RIGHT_ARROW} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_ARROW = (short) 13;
+    /** @deprecated use {@link ShapeType#THICK_ARROW} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_THICKARROW = (short) 14;
+    /** @deprecated use {@link ShapeType#HOME_PLATE} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_HOMEPLATE = (short) 15;
+    /** @deprecated use {@link ShapeType#CUBE} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_CUBE = (short) 16;
+    /** @deprecated use {@link ShapeType#BALLOON} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_BALLOON = (short) 17;
+    /** @deprecated use {@link ShapeType#SEAL} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_SEAL = (short) 18;
+    /** @deprecated use {@link ShapeType#ARC} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_ARC = (short) 19;
+    /** @deprecated use {@link ShapeType#LINE} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_LINE = (short) 20;
+    /** @deprecated use {@link ShapeType#PLAQUE} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_PLAQUE = (short) 21;
+    /** @deprecated use {@link ShapeType#CAN} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_CAN = (short) 22;
+    /** @deprecated use {@link ShapeType#DONUT} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_DONUT = (short) 23;
+    /** @deprecated use {@link ShapeType#TEXT_SIMPLE} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_TEXTSIMPLE = (short) 24;
+    /** @deprecated use {@link ShapeType#TEXT_OCTAGON} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_TEXTOCTAGON = (short) 25;
+    /** @deprecated use {@link ShapeType#TEXT_HEXAGON} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_TEXTHEXAGON = (short) 26;
+    /** @deprecated use {@link ShapeType#TEXT_CURVE} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_TEXTCURVE = (short) 27;
+    /** @deprecated use {@link ShapeType#TEXT_WAVE} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_TEXTWAVE = (short) 28;
+    /** @deprecated use {@link ShapeType#TEXT_RING} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_TEXTRING = (short) 29;
+    /** @deprecated use {@link ShapeType#TEXT_ON_CURVE} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_TEXTONCURVE = (short) 30;
+    /** @deprecated use {@link ShapeType#TEXT_ON_RING} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_TEXTONRING = (short) 31;
+    /** @deprecated use {@link ShapeType#STRAIGHT_CONNECTOR_1} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_STRAIGHTCONNECTOR1 = (short) 32;
+    /** @deprecated use {@link ShapeType#BENT_CONNECTOR_2} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_BENTCONNECTOR2 = (short) 33;
+    /** @deprecated use {@link ShapeType#BENT_CONNECTOR_3} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_BENTCONNECTOR3 = (short) 34;
+    /** @deprecated use {@link ShapeType#BENT_CONNECTOR_4} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_BENTCONNECTOR4 = (short) 35;
+    /** @deprecated use {@link ShapeType#BENT_CONNECTOR_5} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_BENTCONNECTOR5 = (short) 36;
+    /** @deprecated use {@link ShapeType#CURVED_CONNECTOR_2} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_CURVEDCONNECTOR2 = (short) 37;
+    /** @deprecated use {@link ShapeType#CURVED_CONNECTOR_3} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_CURVEDCONNECTOR3 = (short) 38;
+    /** @deprecated use {@link ShapeType#CURVED_CONNECTOR_3} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_CURVEDCONNECTOR4 = (short) 39;
+    /** @deprecated use {@link ShapeType#CURVED_CONNECTOR_5} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_CURVEDCONNECTOR5 = (short) 40;
+    /** @deprecated use {@link ShapeType#CALLOUT_1} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_CALLOUT1 = (short) 41;
+    /** @deprecated use {@link ShapeType#CALLOUT_2} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_CALLOUT2 = (short) 42;
+    /** @deprecated use {@link ShapeType#CALLOUT_3} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_CALLOUT3 = (short) 43;
+    /** @deprecated use {@link ShapeType#ACCENT_CALLOUT_1} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_ACCENTCALLOUT1 = (short) 44;
+    /** @deprecated use {@link ShapeType#ACCENT_CALLOUT_2} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_ACCENTCALLOUT2 = (short) 45;
+    /** @deprecated use {@link ShapeType#ACCENT_CALLOUT_3} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_ACCENTCALLOUT3 = (short) 46;
+    /** @deprecated use {@link ShapeType#BORDER_CALLOUT_1} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_BORDERCALLOUT1 = (short) 47;
+    /** @deprecated use {@link ShapeType#BORDER_CALLOUT_2} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_BORDERCALLOUT2 = (short) 48;
+    /** @deprecated use {@link ShapeType#BORDER_CALLOUT_3} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_BORDERCALLOUT3 = (short) 49;
+    /** @deprecated use {@link ShapeType#ACCENT_BORDER_CALLOUT_1} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_ACCENTBORDERCALLOUT1 = (short) 50;
+    /** @deprecated use {@link ShapeType#ACCENT_BORDER_CALLOUT_2} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_ACCENTBORDERCALLOUT2 = (short) 51;
+    /** @deprecated use {@link ShapeType#ACCENT_BORDER_CALLOUT_3} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_ACCENTBORDERCALLOUT3 = (short) 52;
+    /** @deprecated use {@link ShapeType#RIBBON} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_RIBBON = (short) 53;
+    /** @deprecated use {@link ShapeType#RIBBON_2} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_RIBBON2 = (short) 54;
+    /** @deprecated use {@link ShapeType#CHEVRON} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_CHEVRON = (short) 55;
+    /** @deprecated use {@link ShapeType#PENTAGON} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_PENTAGON = (short) 56;
+    /** @deprecated use {@link ShapeType#NO_SMOKING} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_NOSMOKING = (short) 57;
+    /** @deprecated use {@link ShapeType#STAR_8} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_SEAL8 = (short) 58;
+    /** @deprecated use {@link ShapeType#STAR_16} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_SEAL16 = (short) 59;
+    /** @deprecated use {@link ShapeType#STAR_32} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_SEAL32 = (short) 60;
+    /** @deprecated use {@link ShapeType#WEDGE_RECT_CALLOUT} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_WEDGERECTCALLOUT = (short) 61;
+    /** @deprecated use {@link ShapeType#WEDGE_ROUND_RECT_CALLOUT} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_WEDGERRECTCALLOUT = (short) 62;
+    /** @deprecated use {@link ShapeType#WEDGE_ELLIPSE_CALLOUT} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_WEDGEELLIPSECALLOUT = (short) 63;
+    /** @deprecated use {@link ShapeType#WAVE} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_WAVE = (short) 64;
+    /** @deprecated use {@link ShapeType#FOLDED_CORNER} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_FOLDEDCORNER = (short) 65;
+    /** @deprecated use {@link ShapeType#LEFT_ARROW} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_LEFTARROW = (short) 66;
+    /** @deprecated use {@link ShapeType#DOWN_ARROW} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_DOWNARROW = (short) 67;
+    /** @deprecated use {@link ShapeType#UP_ARROW} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_UPARROW = (short) 68;
+    /** @deprecated use {@link ShapeType#LEFT_RIGHT_ARROW} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_LEFTRIGHTARROW = (short) 69;
+    /** @deprecated use {@link ShapeType#UP_DOWN_ARROW} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_UPDOWNARROW = (short) 70;
+    /** @deprecated use {@link ShapeType#IRREGULAR_SEAL_1} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_IRREGULARSEAL1 = (short) 71;
+    /** @deprecated use {@link ShapeType#IRREGULAR_SEAL_2} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_IRREGULARSEAL2 = (short) 72;
+    /** @deprecated use {@link ShapeType#LIGHTNING_BOLT} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_LIGHTNINGBOLT = (short) 73;
+    /** @deprecated use {@link ShapeType#HEART} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_HEART = (short) 74;
+    /** @deprecated use {@link ShapeType#FRAME} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_PICTUREFRAME = (short) 75;
+    /** @deprecated use {@link ShapeType#QUAD_ARROW} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_QUADARROW = (short) 76;
+    /** @deprecated use {@link ShapeType#LEFT_ARROW_CALLOUT} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_LEFTARROWCALLOUT = (short) 77;
+    /** @deprecated use {@link ShapeType#RIGHT_ARROW_CALLOUT} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_RIGHTARROWCALLOUT = (short) 78;
+    /** @deprecated use {@link ShapeType#UP_ARROW_CALLOUT} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_UPARROWCALLOUT = (short) 79;
+    /** @deprecated use {@link ShapeType#DOWN_ARROW_CALLOUT} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_DOWNARROWCALLOUT = (short) 80;
+    /** @deprecated use {@link ShapeType#LEFT_RIGHT_ARROW_CALLOUT} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_LEFTRIGHTARROWCALLOUT = (short) 81;
+    /** @deprecated use {@link ShapeType#UP_DOWN_ARROW_CALLOUT} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_UPDOWNARROWCALLOUT = (short) 82;
+    /** @deprecated use {@link ShapeType#QUAD_ARROW_CALLOUT} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_QUADARROWCALLOUT = (short) 83;
+    /** @deprecated use {@link ShapeType#BEVEL} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_BEVEL = (short) 84;
+    /** @deprecated use {@link ShapeType#LEFT_BRACKET} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_LEFTBRACKET = (short) 85;
+    /** @deprecated use {@link ShapeType#RIGHT_BRACKET} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_RIGHTBRACKET = (short) 86;
+    /** @deprecated use {@link ShapeType#LEFT_BRACE} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_LEFTBRACE = (short) 87;
+    /** @deprecated use {@link ShapeType#RIGHT_BRACE} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_RIGHTBRACE = (short) 88;
+    /** @deprecated use {@link ShapeType#LEFT_UP_ARROW} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_LEFTUPARROW = (short) 89;
+    /** @deprecated use {@link ShapeType#BENT_UP_ARROW} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_BENTUPARROW = (short) 90;
+    /** @deprecated use {@link ShapeType#BENT_ARROW} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_BENTARROW = (short) 91;
+    /** @deprecated use {@link ShapeType#STAR_24} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_SEAL24 = (short) 92;
+    /** @deprecated use {@link ShapeType#STRIPED_RIGHT_ARROW} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_STRIPEDRIGHTARROW = (short) 93;
+    /** @deprecated use {@link ShapeType#NOTCHED_RIGHT_ARROW} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_NOTCHEDRIGHTARROW = (short) 94;
+    /** @deprecated use {@link ShapeType#BLOCK_ARC} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_BLOCKARC = (short) 95;
+    /** @deprecated use {@link ShapeType#SMILEY_FACE} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_SMILEYFACE = (short) 96;
+    /** @deprecated use {@link ShapeType#VERTICAL_SCROLL} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_VERTICALSCROLL = (short) 97;
+    /** @deprecated use {@link ShapeType#HORIZONTAL_SCROLL} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_HORIZONTALSCROLL = (short) 98;
+    /** @deprecated use {@link ShapeType#CIRCULAR_ARROW} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_CIRCULARARROW = (short) 99;
+    /** @deprecated use {@link ShapeType#NOTCHED_CIRCULAR_ARROW} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_NOTCHEDCIRCULARARROW = (short) 100;
+    /** @deprecated use {@link ShapeType#UTURN_ARROW} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_UTURNARROW = (short) 101;
+    /** @deprecated use {@link ShapeType#CURVED_RIGHT_ARROW} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_CURVEDRIGHTARROW = (short) 102;
+    /** @deprecated use {@link ShapeType#CURVED_LEFT_ARROW} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_CURVEDLEFTARROW = (short) 103;
+    /** @deprecated use {@link ShapeType#CURVED_UP_ARROW} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_CURVEDUPARROW = (short) 104;
+    /** @deprecated use {@link ShapeType#CURVED_DOWN_ARROW} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_CURVEDDOWNARROW = (short) 105;
+    /** @deprecated use {@link ShapeType#CLOUD_CALLOUT} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_CLOUDCALLOUT = (short) 106;
+    /** @deprecated use {@link ShapeType#ELLIPSE_RIBBON} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_ELLIPSERIBBON = (short) 107;
+    /** @deprecated use {@link ShapeType#ELLIPSE_RIBBON_2} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_ELLIPSERIBBON2 = (short) 108;
+    /** @deprecated use {@link ShapeType#FLOW_CHART_PROCESS} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_FLOWCHARTPROCESS = (short) 109;
+    /** @deprecated use {@link ShapeType#FLOW_CHART_DECISION} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_FLOWCHARTDECISION = (short) 110;
+    /** @deprecated use {@link ShapeType#FLOW_CHART_INPUT_OUTPUT} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_FLOWCHARTINPUTOUTPUT = (short) 111;
+    /** @deprecated use {@link ShapeType#FLOW_CHART_PREDEFINED_PROCESS} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_FLOWCHARTPREDEFINEDPROCESS = (short) 112;
+    /** @deprecated use {@link ShapeType#FLOW_CHART_INTERNAL_STORAGE} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_FLOWCHARTINTERNALSTORAGE = (short) 113;
+    /** @deprecated use {@link ShapeType#FLOW_CHART_DOCUMENT} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_FLOWCHARTDOCUMENT = (short) 114;
+    /** @deprecated use {@link ShapeType#FLOW_CHART_MULTIDOCUMENT} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_FLOWCHARTMULTIDOCUMENT = (short) 115;
+    /** @deprecated use {@link ShapeType#FLOW_CHART_TERMINATOR} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_FLOWCHARTTERMINATOR = (short) 116;
+    /** @deprecated use {@link ShapeType#FLOW_CHART_PREPARATION} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_FLOWCHARTPREPARATION = (short) 117;
+    /** @deprecated use {@link ShapeType#FLOW_CHART_MANUAL_INPUT} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_FLOWCHARTMANUALINPUT = (short) 118;
+    /** @deprecated use {@link ShapeType#FLOW_CHART_MANUAL_OPERATION} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_FLOWCHARTMANUALOPERATION = (short) 119;
+    /** @deprecated use {@link ShapeType#FLOW_CHART_CONNECTOR} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_FLOWCHARTCONNECTOR = (short) 120;
+    /** @deprecated use {@link ShapeType#FLOW_CHART_PUNCHED_CARD} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_FLOWCHARTPUNCHEDCARD = (short) 121;
+    /** @deprecated use {@link ShapeType#FLOW_CHART_PUNCHED_TAPE} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_FLOWCHARTPUNCHEDTAPE = (short) 122;
+    /** @deprecated use {@link ShapeType#FLOW_CHART_SUMMING_JUNCTION} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_FLOWCHARTSUMMINGJUNCTION = (short) 123;
+    /** @deprecated use {@link ShapeType#FLOW_CHART_OR} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_FLOWCHARTOR = (short) 124;
+    /** @deprecated use {@link ShapeType#FLOW_CHART_COLLATE} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_FLOWCHARTCOLLATE = (short) 125;
+    /** @deprecated use {@link ShapeType#FLOW_CHART_SORT} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_FLOWCHARTSORT = (short) 126;
+    /** @deprecated use {@link ShapeType#FLOW_CHART_EXTRACT} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_FLOWCHARTEXTRACT = (short) 127;
+    /** @deprecated use {@link ShapeType#FLOW_CHART_MERGE} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_FLOWCHARTMERGE = (short) 128;
+    /** @deprecated use {@link ShapeType#FLOW_CHART_OFFLINE_STORAGE} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_FLOWCHARTOFFLINESTORAGE = (short) 129;
+    /** @deprecated use {@link ShapeType#FLOW_CHART_ONLINE_STORAGE} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_FLOWCHARTONLINESTORAGE = (short) 130;
+    /** @deprecated use {@link ShapeType#FLOW_CHART_MAGNETIC_TAPE} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_FLOWCHARTMAGNETICTAPE = (short) 131;
+    /** @deprecated use {@link ShapeType#FLOW_CHART_MAGNETIC_DISK} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_FLOWCHARTMAGNETICDISK = (short) 132;
+    /** @deprecated use {@link ShapeType#FLOW_CHART_MAGNETIC_DRUM} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_FLOWCHARTMAGNETICDRUM = (short) 133;
+    /** @deprecated use {@link ShapeType#FLOW_CHART_DISPLAY} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_FLOWCHARTDISPLAY = (short) 134;
+    /** @deprecated use {@link ShapeType#FLOW_CHART_DELAY} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_FLOWCHARTDELAY = (short) 135;
+    /** @deprecated use {@link ShapeType#TEXT_PLAIN_TEXT} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_TEXTPLAINTEXT = (short) 136;
+    /** @deprecated use {@link ShapeType#TEXT_STOP} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_TEXTSTOP = (short) 137;
+    /** @deprecated use {@link ShapeType#TEXT_TRIANGLE} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_TEXTTRIANGLE = (short) 138;
+    /** @deprecated use {@link ShapeType#TEXT_TRIANGLE_INVERTED} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_TEXTTRIANGLEINVERTED = (short) 139;
+    /** @deprecated use {@link ShapeType#TEXT_CHEVRON} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_TEXTCHEVRON = (short) 140;
+    /** @deprecated use {@link ShapeType#TEXT_CHEVRON_INVERTED} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_TEXTCHEVRONINVERTED = (short) 141;
+    /** @deprecated use {@link ShapeType#TEXT_RING_INSIDE} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_TEXTRINGINSIDE = (short) 142;
+    /** @deprecated use {@link ShapeType#TEXT_RING_OUTSIDE} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_TEXTRINGOUTSIDE = (short) 143;
+    /** @deprecated use {@link ShapeType#TEXT_ARCH_UP_CURVE} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_TEXTARCHUPCURVE = (short) 144;
+    /** @deprecated use {@link ShapeType#TEXT_ARCH_DOWN_CURVE} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_TEXTARCHDOWNCURVE = (short) 145;
+    /** @deprecated use {@link ShapeType#TEXT_CIRCLE_CURVE} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_TEXTCIRCLECURVE = (short) 146;
+    /** @deprecated use {@link ShapeType#TEXT_BUTTON_CURVE} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_TEXTBUTTONCURVE = (short) 147;
+    /** @deprecated use {@link ShapeType#TEXT_ARCH_UP_POUR} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_TEXTARCHUPPOUR = (short) 148;
+    /** @deprecated use {@link ShapeType#TEXT_ARCH_DOWN_POUR} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_TEXTARCHDOWNPOUR = (short) 149;
+    /** @deprecated use {@link ShapeType#TEXT_CIRCLE_POUR} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_TEXTCIRCLEPOUR = (short) 150;
+    /** @deprecated use {@link ShapeType#TEXT_BUTTON_POUR} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_TEXTBUTTONPOUR = (short) 151;
+    /** @deprecated use {@link ShapeType#TEXT_CURVE_UP} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_TEXTCURVEUP = (short) 152;
+    /** @deprecated use {@link ShapeType#TEXT_CURVE_DOWN} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_TEXTCURVEDOWN = (short) 153;
+    /** @deprecated use {@link ShapeType#TEXT_CASCADE_UP} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_TEXTCASCADEUP = (short) 154;
+    /** @deprecated use {@link ShapeType#TEXT_CASCADE_DOWN} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_TEXTCASCADEDOWN = (short) 155;
+    /** @deprecated use {@link ShapeType#TEXT_WAVE_1} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_TEXTWAVE1 = (short) 156;
+    /** @deprecated use {@link ShapeType#TEXT_WAVE_2} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_TEXTWAVE2 = (short) 157;
+    /** @deprecated use {@link ShapeType#TEXT_WAVE_3} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_TEXTWAVE3 = (short) 158;
+    /** @deprecated use {@link ShapeType#TEXT_WAVE_4} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_TEXTWAVE4 = (short) 159;
+    /** @deprecated use {@link ShapeType#TEXT_INFLATE} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_TEXTINFLATE = (short) 160;
+    /** @deprecated use {@link ShapeType#TEXT_DEFLATE} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_TEXTDEFLATE = (short) 161;
+    /** @deprecated use {@link ShapeType#TEXT_INFLATE_BOTTOM} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_TEXTINFLATEBOTTOM = (short) 162;
+    /** @deprecated use {@link ShapeType#TEXT_DEFLATE_BOTTOM} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_TEXTDEFLATEBOTTOM = (short) 163;
+    /** @deprecated use {@link ShapeType#TEXT_INFLATE_TOP} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_TEXTINFLATETOP = (short) 164;
+    /** @deprecated use {@link ShapeType#TEXT_DEFLATE_TOP} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_TEXTDEFLATETOP = (short) 165;
+    /** @deprecated use {@link ShapeType#TEXT_DEFLATE_INFLATE} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_TEXTDEFLATEINFLATE = (short) 166;
+    /** @deprecated use {@link ShapeType#TEXT_DEFLATE_INFLATE_DEFLATE} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_TEXTDEFLATEINFLATEDEFLATE = (short) 167;
+    /** @deprecated use {@link ShapeType#TEXT_FADE_RIGHT} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_TEXTFADERIGHT = (short) 168;
+    /** @deprecated use {@link ShapeType#TEXT_FADE_LEFT} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_TEXTFADELEFT = (short) 169;
+    /** @deprecated use {@link ShapeType#TEXT_FADE_UP} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_TEXTFADEUP = (short) 170;
+    /** @deprecated use {@link ShapeType#TEXT_FADE_DOWN} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_TEXTFADEDOWN = (short) 171;
+    /** @deprecated use {@link ShapeType#TEXT_SLANT_UP} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_TEXTSLANTUP = (short) 172;
+    /** @deprecated use {@link ShapeType#TEXT_SLANT_DOWN} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_TEXTSLANTDOWN = (short) 173;
+    /** @deprecated use {@link ShapeType#TEXT_CAN_UP} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_TEXTCANUP = (short) 174;
+    /** @deprecated use {@link ShapeType#TEXT_CAN_DOWN} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_TEXTCANDOWN = (short) 175;
+    /** @deprecated use {@link ShapeType#FLOW_CHART_ALTERNATE_PROCESS} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_FLOWCHARTALTERNATEPROCESS = (short) 176;
+    /** @deprecated use {@link ShapeType#FLOW_CHART_OFFPAGE_CONNECTOR} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_FLOWCHARTOFFPAGECONNECTOR = (short) 177;
+    /** @deprecated use {@link ShapeType#CALLOUT_90} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_CALLOUT90 = (short) 178;
+    /** @deprecated use {@link ShapeType#ACCENT_CALLOUT_90} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_ACCENTCALLOUT90 = (short) 179;
+    /** @deprecated use {@link ShapeType#BORDER_CALLOUT_90} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_BORDERCALLOUT90 = (short) 180;
+    /** @deprecated use {@link ShapeType#ACCENT_BORDER_CALLOUT_90} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_ACCENTBORDERCALLOUT90 = (short) 181;
+    /** @deprecated use {@link ShapeType#LEFT_RIGHT_UP_ARROW} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_LEFTRIGHTUPARROW = (short) 182;
+    /** @deprecated use {@link ShapeType#SUN} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_SUN = (short) 183;
+    /** @deprecated use {@link ShapeType#MOON} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_MOON = (short) 184;
+    /** @deprecated use {@link ShapeType#BRACKET_PAIR} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_BRACKETPAIR = (short) 185;
+    /** @deprecated use {@link ShapeType#BRACE_PAIR} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_BRACEPAIR = (short) 186;
+    /** @deprecated use {@link ShapeType#STAR_4} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_SEAL4 = (short) 187;
+    /** @deprecated use {@link ShapeType#DOUBLE_WAVE} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_DOUBLEWAVE = (short) 188;
+    /** @deprecated use {@link ShapeType#ACTION_BUTTON_BLANK} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_ACTIONBUTTONBLANK = (short) 189;
+    /** @deprecated use {@link ShapeType#ACTION_BUTTON_HOME} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_ACTIONBUTTONHOME = (short) 190;
+    /** @deprecated use {@link ShapeType#ACTION_BUTTON_HELP} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_ACTIONBUTTONHELP = (short) 191;
+    /** @deprecated use {@link ShapeType#ACTION_BUTTON_INFORMATION} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_ACTIONBUTTONINFORMATION = (short) 192;
+    /** @deprecated use {@link ShapeType#ACTION_BUTTON_FORWARD_NEXT} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_ACTIONBUTTONFORWARDNEXT = (short) 193;
+    /** @deprecated use {@link ShapeType#ACTION_BUTTON_BACK_PREVIOUS} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_ACTIONBUTTONBACKPREVIOUS = (short) 194;
+    /** @deprecated use {@link ShapeType#ACTION_BUTTON_END} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_ACTIONBUTTONEND = (short) 195;
+    /** @deprecated use {@link ShapeType#ACTION_BUTTON_BEGINNING} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_ACTIONBUTTONBEGINNING = (short) 196;
+    /** @deprecated use {@link ShapeType#ACTION_BUTTON_RETURN} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_ACTIONBUTTONRETURN = (short) 197;
+    /** @deprecated use {@link ShapeType#ACTION_BUTTON_DOCUMENT} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_ACTIONBUTTONDOCUMENT = (short) 198;
+    /** @deprecated use {@link ShapeType#ACTION_BUTTON_SOUND} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_ACTIONBUTTONSOUND = (short) 199;
+    /** @deprecated use {@link ShapeType#ACTION_BUTTON_MOVIE} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_ACTIONBUTTONMOVIE = (short) 200;
+    /** @deprecated use {@link ShapeType#HOST_CONTROL} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_HOSTCONTROL = (short) 201;
+    /** @deprecated use {@link ShapeType#TEXT_BOX} */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_TEXTBOX = (short) 202;
+    /** @deprecated not used */
+    @Deprecated
+    @Removal(version = "5.3")
     public static final short ST_NIL = (short) 0x0FFF;
 
     /**
@@ -330,6 +947,7 @@ public final class EscherAggregate extends AbstractEscherHolderRecord {
     /**
      * @return Returns the current sid.
      */
+    @Override
     public short getSid() {
         return sid;
     }
@@ -402,7 +1020,7 @@ public final class EscherAggregate extends AbstractEscherHolderRecord {
 
     private static class ShapeCollector extends DefaultEscherRecordFactory {
         final List<EscherRecord> objShapes = new ArrayList<>();
-        final ByteArrayOutputStream buffer = new ByteArrayOutputStream();
+        final UnsynchronizedByteArrayOutputStream buffer = new UnsynchronizedByteArrayOutputStream();
 
         void addBytes(byte[] data) {
             try {
@@ -412,6 +1030,7 @@ public final class EscherAggregate extends AbstractEscherHolderRecord {
             }
         }
 
+        @Override
         public EscherRecord createRecord(byte[] data, int offset) {
             EscherRecord r = super.createRecord(data, offset);
             short rid = r.getRecordId();
@@ -423,9 +1042,10 @@ public final class EscherAggregate extends AbstractEscherHolderRecord {
 
         List<EscherRecord> parse(EscherAggregate agg) {
             byte[] buf = buffer.toByteArray();
-            for (int pos = 0, bytesRead; pos < buf.length; pos += bytesRead) {
+            int pos = 0;
+            while (pos < buf.length) {
                 EscherRecord r = createRecord(buf, pos);
-                bytesRead = r.fillFields(buf, pos, this);
+                pos += r.fillFields(buf, pos, this);
                 agg.addEscherRecord(r);
             }
             return objShapes;
@@ -440,6 +1060,7 @@ public final class EscherAggregate extends AbstractEscherHolderRecord {
      * @param data   The byte array to serialize to.
      * @return The number of bytes serialized.
      */
+    @Override
     public int serialize(final int offset, final byte[] data) {
         // Determine buffer size
         List <EscherRecord>records = getEscherRecords();
@@ -450,12 +1071,13 @@ public final class EscherAggregate extends AbstractEscherHolderRecord {
         final List <Integer>spEndingOffsets = new ArrayList<>();
         final List <EscherRecord> shapes = new ArrayList<>();
         int pos = 0;
-        for (Object record : records) {
-            EscherRecord e = (EscherRecord) record;
-            pos += e.serialize(pos, buffer, new EscherSerializationListener() {
+        for (EscherRecord record : records) {
+            pos += record.serialize(pos, buffer, new EscherSerializationListener() {
+                @Override
                 public void beforeRecordSerialize(int offset, short recordId, EscherRecord record) {
                 }
 
+                @Override
                 public void afterRecordSerialize(int offset, short recordId, int size, EscherRecord record) {
                     if (recordId == EscherClientDataRecord.RECORD_ID || recordId == EscherTextboxRecord.RECORD_ID) {
                         spEndingOffsets.add(offset);
@@ -545,6 +1167,7 @@ public final class EscherAggregate extends AbstractEscherHolderRecord {
     /**
      * @return record size, including header size of obj, text, note, drawing, continue records
      */
+    @Override
     public int getRecordSize() {
         // To determine size of aggregate record we have to know size of each DrawingRecord because if DrawingRecord
         // is split into several continue records we have to add header size to total EscherAggregate size
@@ -557,9 +1180,11 @@ public final class EscherAggregate extends AbstractEscherHolderRecord {
         int pos = 0;
         for (EscherRecord e : records) {
             pos += e.serialize(pos, buffer, new EscherSerializationListener() {
+                @Override
                 public void beforeRecordSerialize(int offset, short recordId, EscherRecord record) {
                 }
 
+                @Override
                 public void afterRecordSerialize(int offset, short recordId, int size, EscherRecord record) {
                     if (recordId == EscherClientDataRecord.RECORD_ID || recordId == EscherTextboxRecord.RECORD_ID) {
                         spEndingOffsets.add(offset);
@@ -615,6 +1240,7 @@ public final class EscherAggregate extends AbstractEscherHolderRecord {
     /**
      * @return "ESCHERAGGREGATE"
      */
+    @Override
     protected String getRecordName() {
         return "ESCHERAGGREGATE";
     }
diff --git a/poi/src/main/java/org/apache/poi/hssf/record/FilePassRecord.java b/poi/src/main/java/org/apache/poi/hssf/record/FilePassRecord.java
index a7fccea0c9..cbb73a65e4 100644
--- a/poi/src/main/java/org/apache/poi/hssf/record/FilePassRecord.java
+++ b/poi/src/main/java/org/apache/poi/hssf/record/FilePassRecord.java
@@ -17,11 +17,11 @@
 
 package org.apache.poi.hssf.record;
 
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.util.Map;
 import java.util.function.Supplier;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.EncryptedDocumentException;
 import org.apache.poi.poifs.crypt.EncryptionInfo;
 import org.apache.poi.poifs.crypt.EncryptionMode;
@@ -47,7 +47,7 @@ public final class FilePassRecord extends StandardRecord {
     private static final int ENCRYPTION_OTHER = 1;
 
 	private final int encryptionType;
-    private EncryptionInfo encryptionInfo;
+    private final EncryptionInfo encryptionInfo;
 
 	private FilePassRecord(FilePassRecord other) {
         super(other);
@@ -122,7 +122,7 @@ public final class FilePassRecord extends StandardRecord {
 
 	@Override
     protected int getDataSize() {
-	    ByteArrayOutputStream bos = new ByteArrayOutputStream();
+	    UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream();
 	    LittleEndianOutputStream leos = new LittleEndianOutputStream(bos);
         serialize(leos);
         return bos.size();
diff --git a/poi/src/main/java/org/apache/poi/hssf/record/RecordInputStream.java b/poi/src/main/java/org/apache/poi/hssf/record/RecordInputStream.java
index a8af77c2e1..84c5faf29c 100644
--- a/poi/src/main/java/org/apache/poi/hssf/record/RecordInputStream.java
+++ b/poi/src/main/java/org/apache/poi/hssf/record/RecordInputStream.java
@@ -17,11 +17,11 @@
 
 package org.apache.poi.hssf.record;
 
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.util.Locale;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.hssf.dev.BiffViewer;
 import org.apache.poi.hssf.record.crypto.Biff8DecryptingStream;
 import org.apache.poi.poifs.crypt.EncryptionInfo;
@@ -56,7 +56,6 @@ public final class RecordInputStream implements LittleEndianInput {
 	 * For use in {@link BiffViewer} which may construct {@link Record}s that don't completely
 	 * read all available data.  This exception should never be thrown otherwise.
 	 */
-	@SuppressWarnings("serial")
 	public static final class LeftoverDataException extends RuntimeException {
 		public LeftoverDataException(int sid, int remainingByteCount) {
 			super("Initialisation of record 0x" + Integer.toHexString(sid).toUpperCase(Locale.ROOT)
@@ -311,6 +310,7 @@ public final class RecordInputStream implements LittleEndianInput {
 		return Double.longBitsToDouble(readLong());
 	}
 
+	@Override
 	public void readPlain(byte[] buf, int off, int len) {
 	    readFully(buf, 0, buf.length, true);
 	}
@@ -459,7 +459,7 @@ public final class RecordInputStream implements LittleEndianInput {
      */
     @Deprecated
     public byte[] readAllContinuedRemainder() {
-        ByteArrayOutputStream out = new ByteArrayOutputStream(2 * MAX_RECORD_DATA_SIZE);
+        UnsynchronizedByteArrayOutputStream out = new UnsynchronizedByteArrayOutputStream(2 * MAX_RECORD_DATA_SIZE);
 
         while (true) {
             byte[] b = readRemainder();
@@ -486,7 +486,7 @@ public final class RecordInputStream implements LittleEndianInput {
 
 	/**
 	 *
-	 * @return <code>true</code> when a {@link ContinueRecord} is next.
+	 * @return {@code true} when a {@link ContinueRecord} is next.
 	 */
 	private boolean isContinueNext() {
 		if (_currentDataLength != DATA_LEN_NEEDS_TO_BE_READ && _currentDataOffset != _currentDataLength) {
diff --git a/poi/src/main/java/org/apache/poi/hssf/record/SubRecord.java b/poi/src/main/java/org/apache/poi/hssf/record/SubRecord.java
index 0429267162..e67a9f2ca9 100644
--- a/poi/src/main/java/org/apache/poi/hssf/record/SubRecord.java
+++ b/poi/src/main/java/org/apache/poi/hssf/record/SubRecord.java
@@ -17,13 +17,13 @@
 
 package org.apache.poi.hssf.record;
 
-import java.io.ByteArrayOutputStream;
 import java.util.Arrays;
 import java.util.Map;
 import java.util.function.Function;
 import java.util.function.Supplier;
 import java.util.stream.Collectors;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.common.Duplicatable;
 import org.apache.poi.common.usermodel.GenericRecord;
 import org.apache.poi.util.GenericRecordJsonWriter;
@@ -121,7 +121,7 @@ public abstract class SubRecord implements Duplicatable, GenericRecord {
 	protected abstract int getDataSize();
 	public byte[] serialize() {
 		int size = getDataSize() + 4;
-		ByteArrayOutputStream baos = new ByteArrayOutputStream(size);
+		UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream(size);
 		serialize(new LittleEndianOutputStream(baos));
 		if (baos.size() != size) {
 			throw new RuntimeException("write size mismatch");
@@ -134,7 +134,7 @@ public abstract class SubRecord implements Duplicatable, GenericRecord {
 
     /**
      * Whether this record terminates the sub-record stream.
-     * There are two cases when this method must be overridden and return <code>true</code>
+     * There are two cases when this method must be overridden and return {@code true}
      *  - EndSubRecord (sid = 0x00)
      *  - LbsDataSubRecord (sid = 0x12)
      *
diff --git a/poi/src/main/java/org/apache/poi/hssf/usermodel/HSSFCombobox.java b/poi/src/main/java/org/apache/poi/hssf/usermodel/HSSFCombobox.java
index 262eae5086..7295b74fea 100644
--- a/poi/src/main/java/org/apache/poi/hssf/usermodel/HSSFCombobox.java
+++ b/poi/src/main/java/org/apache/poi/hssf/usermodel/HSSFCombobox.java
@@ -27,15 +27,15 @@ import org.apache.poi.ddf.EscherSimpleProperty;
 import org.apache.poi.ddf.EscherSpRecord;
 import org.apache.poi.hssf.record.CommonObjectDataSubRecord;
 import org.apache.poi.hssf.record.EndSubRecord;
-import org.apache.poi.hssf.record.EscherAggregate;
 import org.apache.poi.hssf.record.FtCblsSubRecord;
 import org.apache.poi.hssf.record.LbsDataSubRecord;
 import org.apache.poi.hssf.record.ObjRecord;
 import org.apache.poi.hssf.record.TextObjectRecord;
+import org.apache.poi.sl.usermodel.ShapeType;
 import org.apache.poi.ss.usermodel.ClientAnchor.AnchorType;
 
 /**
- * 
+ *
  */
 public class HSSFCombobox extends HSSFSimpleShape {
 
@@ -65,7 +65,7 @@ public class HSSFCombobox extends HSSFSimpleShape {
         spContainer.setRecordId(EscherContainerRecord.SP_CONTAINER);
         spContainer.setOptions((short) 0x000F);
         sp.setRecordId(EscherSpRecord.RECORD_ID);
-        sp.setOptions((short) ((EscherAggregate.ST_HOSTCONTROL << 4) | 0x2));
+        sp.setOptions((short) ((ShapeType.HOST_CONTROL.nativeId << 4) | 0x2));
 
         sp.setFlags(EscherSpRecord.FLAG_HAVEANCHOR | EscherSpRecord.FLAG_HASSHAPETYPE);
         opt.setRecordId(EscherOptRecord.RECORD_ID);
diff --git a/poi/src/main/java/org/apache/poi/hssf/usermodel/HSSFPolygon.java b/poi/src/main/java/org/apache/poi/hssf/usermodel/HSSFPolygon.java
index 430fe62798..023b47744b 100644
--- a/poi/src/main/java/org/apache/poi/hssf/usermodel/HSSFPolygon.java
+++ b/poi/src/main/java/org/apache/poi/hssf/usermodel/HSSFPolygon.java
@@ -32,9 +32,9 @@ import org.apache.poi.ddf.EscherSimpleProperty;
 import org.apache.poi.ddf.EscherSpRecord;
 import org.apache.poi.hssf.record.CommonObjectDataSubRecord;
 import org.apache.poi.hssf.record.EndSubRecord;
-import org.apache.poi.hssf.record.EscherAggregate;
 import org.apache.poi.hssf.record.ObjRecord;
 import org.apache.poi.hssf.record.TextObjectRecord;
+import org.apache.poi.sl.usermodel.ShapeType;
 import org.apache.poi.util.LittleEndian;
 
 /**
@@ -65,6 +65,7 @@ public class HSSFPolygon  extends HSSFSimpleShape {
     /**
      * Generates the shape records for this shape.
      */
+    @Override
     protected EscherContainerRecord createSpContainer() {
         EscherContainerRecord spContainer = new EscherContainerRecord();
         EscherSpRecord sp = new EscherSpRecord();
@@ -74,7 +75,7 @@ public class HSSFPolygon  extends HSSFSimpleShape {
         spContainer.setRecordId(EscherContainerRecord.SP_CONTAINER);
         spContainer.setOptions((short) 0x000F);
         sp.setRecordId(EscherSpRecord.RECORD_ID);
-        sp.setOptions((short) ((EscherAggregate.ST_NOT_PRIMATIVE << 4) | 0x2));
+        sp.setOptions((short) ((ShapeType.NOT_PRIMITIVE.nativeId << 4) | 0x2));
         if (getParent() == null) {
             sp.setFlags(EscherSpRecord.FLAG_HAVEANCHOR | EscherSpRecord.FLAG_HASSHAPETYPE);
         } else {
@@ -115,6 +116,7 @@ public class HSSFPolygon  extends HSSFSimpleShape {
     /**
      * Creates the low level OBJ record for this shape.
      */
+    @Override
     protected ObjRecord createObjRecord() {
         ObjRecord obj = new ObjRecord();
         CommonObjectDataSubRecord c = new CommonObjectDataSubRecord();
@@ -216,8 +218,6 @@ public class HSSFPolygon  extends HSSFSimpleShape {
 
     /**
      * Defines the width and height of the points in the polygon
-     * @param width
-     * @param height
      */
     public void setPolygonDrawArea(int width, int height) {
         setPropertyValue(new EscherSimpleProperty(EscherPropertyTypes.GEOMETRY__RIGHT, width));
diff --git a/poi/src/main/java/org/apache/poi/hssf/usermodel/HSSFShape.java b/poi/src/main/java/org/apache/poi/hssf/usermodel/HSSFShape.java
index 964356f5a6..d9c98e3063 100644
--- a/poi/src/main/java/org/apache/poi/hssf/usermodel/HSSFShape.java
+++ b/poi/src/main/java/org/apache/poi/hssf/usermodel/HSSFShape.java
@@ -17,11 +17,6 @@
 
 package org.apache.poi.hssf.usermodel;
 
-import java.io.ByteArrayOutputStream;
-import java.io.IOException;
-
-import org.apache.logging.log4j.LogManager;
-import org.apache.logging.log4j.Logger;
 import org.apache.poi.ddf.EscherBoolProperty;
 import org.apache.poi.ddf.EscherChildAnchorRecord;
 import org.apache.poi.ddf.EscherClientAnchorRecord;
@@ -37,6 +32,7 @@ import org.apache.poi.hssf.record.CommonObjectDataSubRecord;
 import org.apache.poi.hssf.record.ObjRecord;
 import org.apache.poi.ss.usermodel.Shape;
 import org.apache.poi.util.LittleEndian;
+import org.apache.poi.util.LittleEndianConsts;
 import org.apache.poi.util.StringUtil;
 
 /**
@@ -48,8 +44,6 @@ import org.apache.poi.util.StringUtil;
  * setFlipVertical() or setFlipHorizontally().
  */
 public abstract class HSSFShape implements Shape {
-    private static final Logger LOG = LogManager.getLogger(HSSFShape.class);
-
     public static final int LINEWIDTH_ONE_PT = 12700;
     public static final int LINEWIDTH_DEFAULT = 9525;
     public static final int LINESTYLE__COLOR_DEFAULT = 0x08000040;
@@ -85,8 +79,6 @@ public abstract class HSSFShape implements Shape {
 
     /**
      * creates shapes from existing file
-     * @param spContainer
-     * @param objRecord
      */
     public HSSFShape(EscherContainerRecord spContainer, ObjRecord objRecord) {
         this._escherContainer = spContainer;
@@ -115,7 +107,6 @@ public abstract class HSSFShape implements Shape {
      * remove escher container from the patriarch.escherAggregate
      * remove obj, textObj and note records if it's necessary
      * in case of ShapeGroup remove all contained shapes
-     * @param patriarch
      */
     protected abstract void afterRemove(HSSFPatriarch patriarch);
 
@@ -179,7 +170,7 @@ public abstract class HSSFShape implements Shape {
      * @see HSSFClientAnchor
      */
     public void setAnchor(HSSFAnchor anchor) {
-        int i = 0;
+        int i;
         int recordId = -1;
         if (parent == null) {
             if (anchor instanceof HSSFChildAnchor)
@@ -365,18 +356,13 @@ public abstract class HSSFShape implements Shape {
      * @return the rotation, in degrees, that is applied to a shape.
      */
     public int getRotationDegree(){
-        ByteArrayOutputStream bos = new ByteArrayOutputStream();
         EscherSimpleProperty property = getOptRecord().lookup(EscherPropertyTypes.TRANSFORM__ROTATION);
         if (null == property){
             return 0;
         }
-        try {
-            LittleEndian.putInt(property.getPropertyValue(), bos);
-            return LittleEndian.getShort(bos.toByteArray(), 2);
-        } catch (IOException e) {
-            LOG.atError().withThrowable(e).log("can't determine rotation degree");
-            return 0;
-        }
+        byte[] buf = new byte[LittleEndianConsts.INT_SIZE];
+        LittleEndian.putInt(buf, 0, property.getPropertyValue());
+        return LittleEndian.getShort(buf, 2);
     }
 
     /**
@@ -385,7 +371,6 @@ public abstract class HSSFShape implements Shape {
      * Negative values specify rotation in the counterclockwise direction.
      * Rotation occurs around the center of the shape.
      * The default value for this property is 0x00000000
-     * @param value
      */
     public void setRotationDegree(short value){
         setPropertyValue(new EscherSimpleProperty(EscherPropertyTypes.TRANSFORM__ROTATION , (value << 16)));
@@ -415,6 +400,7 @@ public abstract class HSSFShape implements Shape {
     /**
      * @return the name of this shape
      */
+    @Override
     public String getShapeName() {
         EscherOptRecord eor = getOptRecord();
         if (eor == null) {
diff --git a/poi/src/main/java/org/apache/poi/hssf/usermodel/HSSFShapeGroup.java b/poi/src/main/java/org/apache/poi/hssf/usermodel/HSSFShapeGroup.java
index b8001fc651..623409d684 100644
--- a/poi/src/main/java/org/apache/poi/hssf/usermodel/HSSFShapeGroup.java
+++ b/poi/src/main/java/org/apache/poi/hssf/usermodel/HSSFShapeGroup.java
@@ -46,7 +46,7 @@ import org.apache.poi.hssf.record.ObjRecord;
  */
 public class HSSFShapeGroup extends HSSFShape implements HSSFShapeContainer {
     private final List<HSSFShape> shapes = new ArrayList<>();
-    private EscherSpgrRecord _spgrRecord;
+    private final EscherSpgrRecord _spgrRecord;
 
     public HSSFShapeGroup(EscherContainerRecord spgrContainer, ObjRecord objRecord) {
         super(spgrContainer, objRecord);
@@ -56,14 +56,13 @@ public class HSSFShapeGroup extends HSSFShape implements HSSFShapeContainer {
         _spgrRecord = (EscherSpgrRecord) spContainer.getChild(0);
         for (EscherRecord ch : spContainer) {
             switch (EscherRecordTypes.forTypeID(ch.getRecordId())) {
-                case SPGR:
-                    break;
                 case CLIENT_ANCHOR:
                     anchor = new HSSFClientAnchor((EscherClientAnchorRecord) ch);
                     break;
                 case CHILD_ANCHOR:
                     anchor = new HSSFChildAnchor((EscherChildAnchorRecord) ch);
                     break;
+                case SPGR:
                 default:
                     break;
             }
@@ -141,10 +140,12 @@ public class HSSFShapeGroup extends HSSFShape implements HSSFShapeContainer {
     protected void afterRemove(HSSFPatriarch patriarch) {
         patriarch.getBoundAggregate().removeShapeToObjRecord(getEscherContainer().getChildContainers().get(0)
                 .getChildById(EscherClientDataRecord.RECORD_ID));
-        for ( int i=0; i<shapes.size(); i++ ) {
-            HSSFShape shape = shapes.get(i);
-            removeShape(shape);
-            shape.afterRemove(getPatriarch());
+        EscherContainerRecord cont = getEscherContainer();
+        HSSFPatriarch pat = getPatriarch();
+        for (HSSFShape shape : shapes) {
+            if (cont.removeChildRecord(shape.getEscherContainer())){
+                shape.afterRemove(pat);
+            }
         }
         shapes.clear();
     }
@@ -181,6 +182,7 @@ public class HSSFShapeGroup extends HSSFShape implements HSSFShapeContainer {
         return group;
     }
 
+    @Override
     public void addShape(HSSFShape shape) {
         shape.setPatriarch(this.getPatriarch());
         shape.setParent(this);
@@ -267,6 +269,7 @@ public class HSSFShapeGroup extends HSSFShape implements HSSFShapeContainer {
     /**
      * Return all children contained by this shape.
      */
+    @Override
     public List<HSSFShape> getChildren() {
         return Collections.unmodifiableList(shapes);
     }
@@ -275,6 +278,7 @@ public class HSSFShapeGroup extends HSSFShape implements HSSFShapeContainer {
      * Sets the coordinate space of this group.  All children are constrained
      * to these coordinates.
      */
+    @Override
     public void setCoordinates(int x1, int y1, int x2, int y2) {
         _spgrRecord.setRectX1(x1);
         _spgrRecord.setRectX2(x2);
@@ -282,6 +286,7 @@ public class HSSFShapeGroup extends HSSFShape implements HSSFShapeContainer {
         _spgrRecord.setRectY2(y2);
     }
 
+    @Override
     public void clear() {
         ArrayList <HSSFShape> copy = new ArrayList<>(shapes);
         for (HSSFShape shape: copy){
@@ -292,6 +297,7 @@ public class HSSFShapeGroup extends HSSFShape implements HSSFShapeContainer {
     /**
      * The top left x coordinate of this group.
      */
+    @Override
     public int getX1() {
         return _spgrRecord.getRectX1();
     }
@@ -299,6 +305,7 @@ public class HSSFShapeGroup extends HSSFShape implements HSSFShapeContainer {
     /**
      * The top left y coordinate of this group.
      */
+    @Override
     public int getY1() {
         return _spgrRecord.getRectY1();
     }
@@ -306,6 +313,7 @@ public class HSSFShapeGroup extends HSSFShape implements HSSFShapeContainer {
     /**
      * The bottom right x coordinate of this group.
      */
+    @Override
     public int getX2() {
         return _spgrRecord.getRectX2();
     }
@@ -313,6 +321,7 @@ public class HSSFShapeGroup extends HSSFShape implements HSSFShapeContainer {
     /**
      * The bottom right y coordinate of this group.
      */
+    @Override
     public int getY2() {
         return _spgrRecord.getRectY2();
     }
@@ -320,6 +329,7 @@ public class HSSFShapeGroup extends HSSFShape implements HSSFShapeContainer {
     /**
      * Count of all children and their childrens children.
      */
+    @Override
     public int countOfAllChildren() {
         int count = shapes.size();
         for (HSSFShape shape : shapes) {
@@ -386,10 +396,11 @@ public class HSSFShapeGroup extends HSSFShape implements HSSFShapeContainer {
         return group;
     }
 
+    @Override
     public boolean removeShape(HSSFShape shape) {
         boolean  isRemoved = getEscherContainer().removeChildRecord(shape.getEscherContainer());
         if (isRemoved){
-            shape.afterRemove(this.getPatriarch());
+            shape.afterRemove(getPatriarch());
             shapes.remove(shape);
         }
         return isRemoved;
diff --git a/poi/src/main/java/org/apache/poi/hssf/usermodel/HSSFTextbox.java b/poi/src/main/java/org/apache/poi/hssf/usermodel/HSSFTextbox.java
index 5821a42f57..0a394d601b 100644
--- a/poi/src/main/java/org/apache/poi/hssf/usermodel/HSSFTextbox.java
+++ b/poi/src/main/java/org/apache/poi/hssf/usermodel/HSSFTextbox.java
@@ -33,6 +33,7 @@ import org.apache.poi.hssf.record.EndSubRecord;
 import org.apache.poi.hssf.record.EscherAggregate;
 import org.apache.poi.hssf.record.ObjRecord;
 import org.apache.poi.hssf.record.TextObjectRecord;
+import org.apache.poi.sl.usermodel.ShapeType;
 
 /**
  * A textbox is a shape that may hold a rich text string.
@@ -68,7 +69,7 @@ public class HSSFTextbox extends HSSFSimpleShape {
     /**
      * Construct a new textbox with the given parent and anchor.
      *
-     * @param parent
+     * @param parent the parent shape
      * @param anchor One of HSSFClientAnchor or HSSFChildAnchor
      */
     public HSSFTextbox(HSSFShape parent, HSSFAnchor anchor) {
@@ -104,7 +105,7 @@ public class HSSFTextbox extends HSSFSimpleShape {
         spContainer.setRecordId(EscherContainerRecord.SP_CONTAINER);
         spContainer.setOptions((short) 0x000F);
         sp.setRecordId(EscherSpRecord.RECORD_ID);
-        sp.setOptions((short) ((EscherAggregate.ST_TEXTBOX << 4) | 0x2));
+        sp.setOptions((short) ((ShapeType.TEXT_BOX.nativeId << 4) | 0x2));
 
         sp.setFlags(EscherSpRecord.FLAG_HAVEANCHOR | EscherSpRecord.FLAG_HASSHAPETYPE);
         opt.setRecordId(EscherOptRecord.RECORD_ID);
diff --git a/poi/src/main/java/org/apache/poi/hssf/usermodel/HSSFWorkbook.java b/poi/src/main/java/org/apache/poi/hssf/usermodel/HSSFWorkbook.java
index dc938d2de7..7a943a368e 100644
--- a/poi/src/main/java/org/apache/poi/hssf/usermodel/HSSFWorkbook.java
+++ b/poi/src/main/java/org/apache/poi/hssf/usermodel/HSSFWorkbook.java
@@ -23,7 +23,6 @@ import static org.apache.poi.hssf.model.InternalWorkbook.WORKBOOK_DIR_ENTRY_NAME
 
 import java.io.BufferedOutputStream;
 import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.FileOutputStream;
 import java.io.IOException;
@@ -47,6 +46,7 @@ import java.util.Set;
 import java.util.regex.Pattern;
 
 import org.apache.commons.codec.digest.DigestUtils;
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.poi.EncryptedDocumentException;
@@ -942,7 +942,6 @@ public final class HSSFWorkbook extends POIDocument implements Workbook {
 
     private final class SheetIterator<T extends Sheet> implements Iterator<T> {
         final private Iterator<T> it;
-        private T cursor;
 
         @SuppressWarnings("unchecked")
         public SheetIterator() {
@@ -956,8 +955,7 @@ public final class HSSFWorkbook extends POIDocument implements Workbook {
 
         @Override
         public T next() throws NoSuchElementException {
-            cursor = it.next();
-            return cursor;
+            return it.next();
         }
 
         /**
@@ -1994,9 +1992,10 @@ public final class HSSFWorkbook extends POIDocument implements Workbook {
             }
         }
 
-        ByteArrayOutputStream bos = new ByteArrayOutputStream();
-        poiData.writeFilesystem(bos);
-        return addOlePackage(bos.toByteArray(), label, fileName, command);
+        try (UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream()) {
+            poiData.writeFilesystem(bos);
+            return addOlePackage(bos.toByteArray(), label, fileName, command);
+        }
     }
 
     @Override
@@ -2021,9 +2020,10 @@ public final class HSSFWorkbook extends POIDocument implements Workbook {
         Ole10Native.createOleMarkerEntry(oleDir);
 
         Ole10Native oleNative = new Ole10Native(label, fileName, command, oleData);
-        ByteArrayOutputStream bos = new ByteArrayOutputStream();
-        oleNative.writeOut(bos);
-        oleDir.createDocument(Ole10Native.OLE10_NATIVE, new ByteArrayInputStream(bos.toByteArray()));
+        try (UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream()) {
+            oleNative.writeOut(bos);
+            oleDir.createDocument(Ole10Native.OLE10_NATIVE, bos.toInputStream());
+        }
 
         return storageId;
     }
diff --git a/poi/src/main/java/org/apache/poi/poifs/crypt/cryptoapi/CryptoAPIDecryptor.java b/poi/src/main/java/org/apache/poi/poifs/crypt/cryptoapi/CryptoAPIDecryptor.java
index df2a51bc38..36b44efbcc 100644
--- a/poi/src/main/java/org/apache/poi/poifs/crypt/cryptoapi/CryptoAPIDecryptor.java
+++ b/poi/src/main/java/org/apache/poi/poifs/crypt/cryptoapi/CryptoAPIDecryptor.java
@@ -17,7 +17,6 @@
 
 package org.apache.poi.poifs.crypt.cryptoapi;
 
-import java.io.ByteArrayOutputStream;
 import java.io.EOFException;
 import java.io.IOException;
 import java.io.InputStream;
@@ -29,6 +28,7 @@ import javax.crypto.Cipher;
 import javax.crypto.SecretKey;
 import javax.crypto.spec.SecretKeySpec;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.EncryptedDocumentException;
 import org.apache.poi.poifs.crypt.ChunkedCipherInputStream;
 import org.apache.poi.poifs.crypt.CryptoFunctions;
@@ -43,7 +43,7 @@ import org.apache.poi.poifs.filesystem.DocumentNode;
 import org.apache.poi.poifs.filesystem.POIFSFileSystem;
 import org.apache.poi.util.BitField;
 import org.apache.poi.util.BitFieldFactory;
-import org.apache.poi.util.BoundedInputStream;
+import org.apache.commons.io.input.BoundedInputStream;
 import org.apache.poi.util.IOUtils;
 import org.apache.poi.util.LittleEndian;
 import org.apache.poi.util.LittleEndianInputStream;
@@ -171,10 +171,10 @@ public class CryptoAPIDecryptor extends Decryptor {
     public POIFSFileSystem getSummaryEntries(DirectoryNode root, String encryptedStream)
     throws IOException, GeneralSecurityException {
         DocumentNode es = (DocumentNode) root.getEntry(encryptedStream);
-        DocumentInputStream dis = root.createDocumentInputStream(es);
-        ByteArrayOutputStream bos = new ByteArrayOutputStream();
-        IOUtils.copy(dis, bos);
-        dis.close();
+        UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream();
+        try (DocumentInputStream dis = root.createDocumentInputStream(es)) {
+            IOUtils.copy(dis, bos);
+        }
         POIFSFileSystem fsOut = null;
         try (
             CryptoAPIDocumentInputStream sbis = new CryptoAPIDocumentInputStream(this, bos.toByteArray());
diff --git a/poi/src/main/java/org/apache/poi/poifs/crypt/cryptoapi/CryptoAPIDocumentOutputStream.java b/poi/src/main/java/org/apache/poi/poifs/crypt/cryptoapi/CryptoAPIDocumentOutputStream.java
index 3a9cae9b04..34c4a74675 100644
--- a/poi/src/main/java/org/apache/poi/poifs/crypt/cryptoapi/CryptoAPIDocumentOutputStream.java
+++ b/poi/src/main/java/org/apache/poi/poifs/crypt/cryptoapi/CryptoAPIDocumentOutputStream.java
@@ -16,11 +16,13 @@
 ==================================================================== */
 package org.apache.poi.poifs.crypt.cryptoapi;
 
-import java.io.ByteArrayOutputStream;
+import java.io.InputStream;
 import java.security.GeneralSecurityException;
 
 import javax.crypto.Cipher;
 
+import org.apache.commons.io.input.BoundedInputStream;
+import org.apache.commons.io.output.ByteArrayOutputStream;
 import org.apache.poi.EncryptedDocumentException;
 import org.apache.poi.util.Internal;
 
@@ -38,8 +40,8 @@ import org.apache.poi.util.Internal;
         cipher = encryptor.initCipherForBlock(null, 0);
     }
 
-    public byte[] getBuf() {
-        return buf;
+    public InputStream toInputStream(long maxSize) {
+        return new BoundedInputStream(toInputStream(), maxSize);
     }
 
     public void setSize(int count) {
diff --git a/poi/src/main/java/org/apache/poi/poifs/crypt/cryptoapi/CryptoAPIEncryptor.java b/poi/src/main/java/org/apache/poi/poifs/crypt/cryptoapi/CryptoAPIEncryptor.java
index 652e7f51d7..176f431eec 100644
--- a/poi/src/main/java/org/apache/poi/poifs/crypt/cryptoapi/CryptoAPIEncryptor.java
+++ b/poi/src/main/java/org/apache/poi/poifs/crypt/cryptoapi/CryptoAPIEncryptor.java
@@ -17,7 +17,6 @@
 
 package org.apache.poi.poifs.crypt.cryptoapi;
 
-import java.io.ByteArrayInputStream;
 import java.io.File;
 import java.io.IOException;
 import java.io.OutputStream;
@@ -188,7 +187,7 @@ public class CryptoAPIEncryptor extends Encryptor {
         bos.write(buf, 0, 8);
         bos.setSize(savedSize);
 
-        dir.createDocument(encryptedStream, new ByteArrayInputStream(bos.getBuf(), 0, savedSize));
+        dir.createDocument(encryptedStream, bos.toInputStream(savedSize));
     }
 
 //    protected int getKeySizeInBytes() {
diff --git a/poi/src/main/java/org/apache/poi/poifs/crypt/standard/StandardDecryptor.java b/poi/src/main/java/org/apache/poi/poifs/crypt/standard/StandardDecryptor.java
index 9fedce6122..1624fa97e2 100644
--- a/poi/src/main/java/org/apache/poi/poifs/crypt/standard/StandardDecryptor.java
+++ b/poi/src/main/java/org/apache/poi/poifs/crypt/standard/StandardDecryptor.java
@@ -38,7 +38,7 @@ import org.apache.poi.poifs.crypt.EncryptionVerifier;
 import org.apache.poi.poifs.crypt.HashAlgorithm;
 import org.apache.poi.poifs.filesystem.DirectoryNode;
 import org.apache.poi.poifs.filesystem.DocumentInputStream;
-import org.apache.poi.util.BoundedInputStream;
+import org.apache.commons.io.input.BoundedInputStream;
 import org.apache.poi.util.LittleEndian;
 
 /**
diff --git a/poi/src/main/java/org/apache/poi/poifs/filesystem/DocumentOutputStream.java b/poi/src/main/java/org/apache/poi/poifs/filesystem/DocumentOutputStream.java
index a1052d865c..f8b948ee38 100644
--- a/poi/src/main/java/org/apache/poi/poifs/filesystem/DocumentOutputStream.java
+++ b/poi/src/main/java/org/apache/poi/poifs/filesystem/DocumentOutputStream.java
@@ -18,10 +18,10 @@
 package org.apache.poi.poifs.filesystem;
 
 import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.OutputStream;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.poifs.common.POIFSConstants;
 import org.apache.poi.poifs.property.DocumentProperty;
 
@@ -37,13 +37,13 @@ public final class DocumentOutputStream extends OutputStream {
 	private boolean _closed = false;
 
 	/** the actual Document */
-	private POIFSDocument _document;
+	private final POIFSDocument _document;
 	/** and its Property */
-	private DocumentProperty _property;
+	private final DocumentProperty _property;
 
 	/** our buffer, when null we're into normal blocks */
-	private ByteArrayOutputStream _buffer =
-	        new ByteArrayOutputStream(POIFSConstants.BIG_BLOCK_MINIMUM_DOCUMENT_SIZE);
+	private UnsynchronizedByteArrayOutputStream _buffer =
+	        new UnsynchronizedByteArrayOutputStream(POIFSConstants.BIG_BLOCK_MINIMUM_DOCUMENT_SIZE);
 
 	/** our main block stream, when we're into normal blocks */
 	private POIFSStream _stream;
@@ -115,11 +115,11 @@ public final class DocumentOutputStream extends OutputStream {
             byte[] data = _buffer.toByteArray();
             _buffer = null;
             write(data, 0, data.length);
-        } else {
-            // So far, mini stream will work, keep going
         }
+        // otherwise mini stream will work, keep going
     }
 
+    @Override
     public void write(int b) throws IOException {
         write(new byte[] { (byte)b }, 0, 1);
     }
@@ -146,11 +146,12 @@ public final class DocumentOutputStream extends OutputStream {
         }
     }
 
+    @Override
     public void close() throws IOException {
         // Do we have a pending buffer for the mini stream?
         if (_buffer != null) {
             // It's not much data, so ask POIFSDocument to do it for us
-            _document.replaceContents(new ByteArrayInputStream(_buffer.toByteArray()));
+            _document.replaceContents(_buffer.toInputStream());
         }
         else {
             // We've been writing to the stream as we've gone along
diff --git a/poi/src/main/java/org/apache/poi/poifs/filesystem/EntryUtils.java b/poi/src/main/java/org/apache/poi/poifs/filesystem/EntryUtils.java
index bd21697fcf..81dd891a8c 100644
--- a/poi/src/main/java/org/apache/poi/poifs/filesystem/EntryUtils.java
+++ b/poi/src/main/java/org/apache/poi/poifs/filesystem/EntryUtils.java
@@ -25,7 +25,6 @@ import java.util.Objects;
 import java.util.stream.Collectors;
 import java.util.stream.StreamSupport;
 
-import org.apache.poi.hpsf.MarkUnsupportedException;
 import org.apache.poi.hpsf.NoPropertySetStreamException;
 import org.apache.poi.hpsf.PropertySet;
 import org.apache.poi.hpsf.PropertySetFactory;
@@ -238,7 +237,7 @@ public final class EntryUtils {
                 } else {
                     return isEqual(inpA, inpB);
                 }
-            } catch (MarkUnsupportedException | NoPropertySetStreamException | IOException ex) {
+            } catch (NoPropertySetStreamException | IOException ex) {
                 throw new RuntimeException(ex);
             }
         }
diff --git a/poi/src/main/java/org/apache/poi/poifs/filesystem/Ole10Native.java b/poi/src/main/java/org/apache/poi/poifs/filesystem/Ole10Native.java
index c2d4a73ae4..680763bac2 100644
--- a/poi/src/main/java/org/apache/poi/poifs/filesystem/Ole10Native.java
+++ b/poi/src/main/java/org/apache/poi/poifs/filesystem/Ole10Native.java
@@ -18,12 +18,12 @@
 package org.apache.poi.poifs.filesystem;
 
 import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.OutputStream;
 import java.nio.charset.Charset;
 import java.nio.charset.StandardCharsets;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.util.IOUtils;
 import org.apache.poi.util.LittleEndianByteArrayInputStream;
 import org.apache.poi.util.LittleEndianConsts;
@@ -336,7 +336,7 @@ public class Ole10Native {
     /**
      * Returns the size of the embedded file. If the size is 0 (zero), no data
      * has been embedded. To be sure, that no data has been embedded, check
-     * whether {@link #getDataBuffer()} returns <code>null</code>.
+     * whether {@link #getDataBuffer()} returns {@code null}.
      *
      * @return the dataSize
      */
@@ -346,10 +346,10 @@ public class Ole10Native {
 
     /**
      * Returns the buffer containing the embedded file's data, or
-     * <code>null</code> if no data was embedded. Note that an embedding may
+     * {@code null} if no data was embedded. Note that an embedding may
      * provide information about the data, but the actual data is not included.
      * (So label, filename etc. are available, but this method returns
-     * <code>null</code>.)
+     * {@code null}.)
      *
      * @return the dataBuffer
      */
@@ -372,7 +372,7 @@ public class Ole10Native {
 
         switch (mode) {
             case parsed: {
-                ByteArrayOutputStream bos = new ByteArrayOutputStream();
+                UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream();
                 try (LittleEndianOutputStream leos = new LittleEndianOutputStream(bos)) {
                     // total size, will be determined later ..
 
diff --git a/poi/src/main/java/org/apache/poi/poifs/filesystem/POIFSFileSystem.java b/poi/src/main/java/org/apache/poi/poifs/filesystem/POIFSFileSystem.java
index 7ac288a8a8..ebee94394b 100644
--- a/poi/src/main/java/org/apache/poi/poifs/filesystem/POIFSFileSystem.java
+++ b/poi/src/main/java/org/apache/poi/poifs/filesystem/POIFSFileSystem.java
@@ -16,7 +16,6 @@
 ==================================================================== */
 package org.apache.poi.poifs.filesystem;
 
-import java.io.ByteArrayOutputStream;
 import java.io.Closeable;
 import java.io.File;
 import java.io.FileInputStream;
@@ -33,6 +32,7 @@ import java.util.Collections;
 import java.util.Iterator;
 import java.util.List;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.commons.math3.util.ArithmeticUtils;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
@@ -733,7 +733,7 @@ public class POIFSFileSystem extends BlockStore
         // _header.setPropertyStart has been updated on write ...
 
         // HeaderBlock
-        ByteArrayOutputStream baos = new ByteArrayOutputStream(
+        UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream(
                 _header.getBigBlockSize().getBigBlockSize()
         );
         _header.writeData(baos);
diff --git a/poi/src/main/java/org/apache/poi/poifs/macros/VBAMacroReader.java b/poi/src/main/java/org/apache/poi/poifs/macros/VBAMacroReader.java
index 76cfd66472..049a805318 100644
--- a/poi/src/main/java/org/apache/poi/poifs/macros/VBAMacroReader.java
+++ b/poi/src/main/java/org/apache/poi/poifs/macros/VBAMacroReader.java
@@ -22,7 +22,6 @@ import static org.apache.poi.util.StringUtil.endsWithIgnoreCase;
 import static org.apache.poi.util.StringUtil.startsWithIgnoreCase;
 
 import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.Closeable;
 import java.io.EOFException;
 import java.io.File;
@@ -38,6 +37,7 @@ import java.util.Map;
 import java.util.zip.ZipEntry;
 import java.util.zip.ZipInputStream;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.poi.poifs.filesystem.DirectoryNode;
@@ -167,10 +167,7 @@ public class VBAMacroReader implements Closeable {
         ModuleType moduleType;
         Charset charset;
         void read(InputStream in) throws IOException {
-            final ByteArrayOutputStream out = new ByteArrayOutputStream();
-            IOUtils.copy(in, out);
-            out.close();
-            buf = out.toByteArray();
+            buf = IOUtils.toByteArray(in);
         }
         @Override
         public String getContent() {
@@ -414,13 +411,12 @@ public class VBAMacroReader implements Closeable {
         UNKNOWN(-2);
 
 
-        private final int VARIABLE_LENGTH = -1;
         private final int id;
         private final int constantLength;
 
         RecordType(int id) {
             this.id = id;
-            this.constantLength = VARIABLE_LENGTH;
+            this.constantLength = -1;
         }
 
         RecordType(int id, int constantLength) {
@@ -651,13 +647,13 @@ public class VBAMacroReader implements Closeable {
                         return;
                     }
                 }
-                mbcs = readMBCS(b, is, charset, MAX_STRING_LENGTH);
+                mbcs = readMBCS(b, is, charset);
             } catch (EOFException e) {
                 return;
             }
 
             try {
-                unicode = readUnicode(is, MAX_STRING_LENGTH);
+                unicode = readUnicode(is);
             } catch (EOFException e) {
                 return;
             }
@@ -669,14 +665,14 @@ public class VBAMacroReader implements Closeable {
         LOGGER.atWarn().log("Hit max name records to read (" + maxNameRecords + "). Stopped early.");
     }
 
-    private static String readUnicode(InputStream is, int maxLength) throws IOException {
+    private static String readUnicode(InputStream is) throws IOException {
         //reads null-terminated unicode string
-        ByteArrayOutputStream bos = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream();
         int b0 = IOUtils.readByte(is);
         int b1 = IOUtils.readByte(is);
 
         int read = 2;
-        while ((b0 + b1) != 0 && read < maxLength) {
+        while ((b0 + b1) != 0 && read < MAX_STRING_LENGTH) {
 
             bos.write(b0);
             bos.write(b1);
@@ -684,22 +680,22 @@ public class VBAMacroReader implements Closeable {
             b1 = IOUtils.readByte(is);
             read += 2;
         }
-        if (read >= maxLength) {
+        if (read >= MAX_STRING_LENGTH) {
             LOGGER.atWarn().log("stopped reading unicode name after {} bytes", box(read));
         }
-        return new String (bos.toByteArray(), StandardCharsets.UTF_16LE);
+        return bos.toString(StandardCharsets.UTF_16LE);
     }
 
-    private static String readMBCS(int firstByte, InputStream is, Charset charset, int maxLength) throws IOException {
-        ByteArrayOutputStream bos = new ByteArrayOutputStream();
+    private static String readMBCS(int firstByte, InputStream is, Charset charset) throws IOException {
+        UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream();
         int len = 0;
         int b = firstByte;
-        while (b > 0 && len < maxLength) {
+        while (b > 0 && len < MAX_STRING_LENGTH) {
             ++len;
             bos.write(b);
             b = IOUtils.readByte(is);
         }
-        return new String(bos.toByteArray(), charset);
+        return bos.toString(charset);
     }
 
     /**
@@ -796,7 +792,7 @@ public class VBAMacroReader implements Closeable {
      */
     private static byte[] findCompressedStreamWBruteForce(InputStream is) throws IOException {
         //buffer to memory for multiple tries
-        ByteArrayOutputStream bos = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream();
         IOUtils.copy(is, bos);
         byte[] compressed = bos.toByteArray();
         byte[] decompressed = null;
@@ -825,7 +821,7 @@ public class VBAMacroReader implements Closeable {
     }
 
     private static byte[] tryToDecompress(InputStream is) {
-        ByteArrayOutputStream bos = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream();
         try {
             IOUtils.copy(new RLEDecompressingInputStream(is), bos);
         } catch (IllegalArgumentException | IOException | IllegalStateException e){
diff --git a/poi/src/main/java/org/apache/poi/sl/draw/BitmapImageRenderer.java b/poi/src/main/java/org/apache/poi/sl/draw/BitmapImageRenderer.java
index aa2b13e64c..4f2ca0ffbb 100644
--- a/poi/src/main/java/org/apache/poi/sl/draw/BitmapImageRenderer.java
+++ b/poi/src/main/java/org/apache/poi/sl/draw/BitmapImageRenderer.java
@@ -28,7 +28,6 @@ import java.awt.image.AffineTransformOp;
 import java.awt.image.BufferedImage;
 import java.awt.image.RescaleOp;
 import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.util.Iterator;
@@ -40,6 +39,7 @@ import javax.imageio.ImageTypeSpecifier;
 import javax.imageio.stream.ImageInputStream;
 import javax.imageio.stream.MemoryCacheImageInputStream;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.poi.sl.usermodel.PictureData.PictureType;
@@ -73,11 +73,11 @@ public class BitmapImageRenderer implements ImageRenderer {
     public void loadImage(InputStream data, String contentType) throws IOException {
         InputStream in = data;
         if (doCache) {
-            ByteArrayOutputStream bos = new ByteArrayOutputStream();
+            UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream();
             IOUtils.copy(data, bos);
             cachedImage = bos.toByteArray();
             cachedContentType = contentType;
-            in = new ByteArrayInputStream(cachedImage);
+            in = bos.toInputStream();
         }
         img = readImage(in, contentType);
     }
@@ -107,13 +107,13 @@ public class BitmapImageRenderer implements ImageRenderer {
         IOException lastException = null;
         BufferedImage img = null;
 
-        final ByteArrayInputStream bis;
+        final InputStream bis;
         if (data instanceof ByteArrayInputStream) {
-            bis = (ByteArrayInputStream)data;
+            bis = data;
         } else {
-            ByteArrayOutputStream bos = new ByteArrayOutputStream(0x3FFFF);
+            UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream(0x3FFFF);
             IOUtils.copy(data, bos);
-            bis = new ByteArrayInputStream(bos.toByteArray());
+            bis = bos.toInputStream();
         }
 
 
@@ -257,7 +257,7 @@ public class BitmapImageRenderer implements ImageRenderer {
     @Override
     public BufferedImage getImage(Dimension2D dim) {
         if (img == null) {
-            return img;
+            return null;
         }
         double w_old = img.getWidth();
         double h_old = img.getHeight();
diff --git a/poi/src/main/java/org/apache/poi/sl/usermodel/ObjectShape.java b/poi/src/main/java/org/apache/poi/sl/usermodel/ObjectShape.java
index c7d421950e..3c36c77827 100644
--- a/poi/src/main/java/org/apache/poi/sl/usermodel/ObjectShape.java
+++ b/poi/src/main/java/org/apache/poi/sl/usermodel/ObjectShape.java
@@ -17,12 +17,11 @@
 
 package org.apache.poi.sl.usermodel;
 
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.poifs.filesystem.DirectoryNode;
 import org.apache.poi.poifs.filesystem.FileMagic;
 import org.apache.poi.poifs.filesystem.POIFSFileSystem;
@@ -54,7 +53,7 @@ public interface ObjectShape<
      * @return the ProgID
      */
     String getProgId();
-    
+
     /**
      * Returns the full name of the embedded object,
      *  e.g. "Microsoft Word Document" or "Microsoft Office Excel Worksheet".
@@ -62,11 +61,11 @@ public interface ObjectShape<
      * @return the full name of the embedded object
      */
     String getFullName();
-    
+
     /**
      * Updates the ole data. If there wasn't an object registered before, a new
      * ole embedding is registered in the parent slideshow.<p>
-     * 
+     *
      * For HSLF this needs to be a {@link POIFSFileSystem} stream.
      *
      * @param application a preset application enum
@@ -81,10 +80,10 @@ public interface ObjectShape<
     /**
      * Reads the ole data as stream - the application specific stream is served
      * The {@link #readObjectDataRaw() raw data} serves the outer/wrapped object, which is usually a
-     * {@link POIFSFileSystem} stream, whereas this method return the unwrapped entry 
+     * {@link POIFSFileSystem} stream, whereas this method return the unwrapped entry
      *
      * @return an {@link InputStream} which serves the object data
-     * 
+     *
      * @throws IOException if the linked object data couldn't be found
      */
     default InputStream readObjectData() throws IOException {
@@ -97,8 +96,9 @@ public interface ObjectShape<
 
         final Application app = Application.lookup(progId);
 
-        final ByteArrayOutputStream bos = new ByteArrayOutputStream(50000);
-        try (final InputStream is = FileMagic.prepareToCheckMagic(readObjectDataRaw())) {
+        try (final UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream();
+             final InputStream is = FileMagic.prepareToCheckMagic(readObjectDataRaw())) {
+
             final FileMagic fm = FileMagic.valueOf(is);
             if (fm == FileMagic.OLE2) {
                 try (final POIFSFileSystem poifs = new POIFSFileSystem(is)) {
@@ -129,11 +129,10 @@ public interface ObjectShape<
             } else {
                 IOUtils.copy(is, bos);
             }
+            return bos.toInputStream();
         }
-
-        return new ByteArrayInputStream(bos.toByteArray());
     }
-    
+
     /**
      * Convenience method to return the raw data as {@code InputStream}
      *
diff --git a/poi/src/main/java/org/apache/poi/ss/extractor/EmbeddedExtractor.java b/poi/src/main/java/org/apache/poi/ss/extractor/EmbeddedExtractor.java
index dbce0249ea..18eef73108 100644
--- a/poi/src/main/java/org/apache/poi/ss/extractor/EmbeddedExtractor.java
+++ b/poi/src/main/java/org/apache/poi/ss/extractor/EmbeddedExtractor.java
@@ -19,7 +19,6 @@ package org.apache.poi.ss.extractor;
 
 import static org.apache.poi.util.StringUtil.endsWithIgnoreCase;
 
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.util.ArrayList;
@@ -28,6 +27,7 @@ import java.util.Collections;
 import java.util.Iterator;
 import java.util.List;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.poi.hpsf.ClassID;
@@ -162,7 +162,7 @@ public class EmbeddedExtractor implements Iterable<EmbeddedExtractor> {
 
     protected EmbeddedData extract(DirectoryNode dn) throws IOException {
         assert(canExtract(dn));
-        ByteArrayOutputStream bos = new ByteArrayOutputStream(20000);
+        UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream(20000);
         try (POIFSFileSystem dest = new POIFSFileSystem()) {
             copyNodes(dn, dest.getRoot());
             // start with a reasonable big size
@@ -204,7 +204,7 @@ public class EmbeddedExtractor implements Iterable<EmbeddedExtractor> {
 
         @Override
         public EmbeddedData extract(DirectoryNode dn) throws IOException {
-            try(ByteArrayOutputStream bos = new ByteArrayOutputStream();
+            try(UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream();
                 InputStream is = dn.createDocumentInputStream("CONTENTS")) {
                 IOUtils.copy(is, bos);
                 return new EmbeddedData(dn.getName() + ".pdf", bos.toByteArray(), CONTENT_TYPE_PDF);
diff --git a/poi/src/main/java/org/apache/poi/util/BoundedInputStream.java b/poi/src/main/java/org/apache/poi/util/BoundedInputStream.java
deleted file mode 100644
index df63cbc11b..0000000000
--- a/poi/src/main/java/org/apache/poi/util/BoundedInputStream.java
+++ /dev/null
@@ -1,231 +0,0 @@
-/*
- * Licensed to the Apache Software Foundation (ASF) under one or more
- * contributor license agreements.  See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership.
- * The ASF licenses this file to You under the Apache License, Version 2.0
- * (the "License"); you may not use this file except in compliance with
- * the License.  You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package org.apache.poi.util;
-
-import java.io.IOException;
-import java.io.InputStream;
-
-/**
- * This is a stream that will only supply bytes up to a certain length - if its
- * position goes above that, it will stop.
- * <p>
- * This is useful to wrap ServletInputStreams. The ServletInputStream will block
- * if you try to read content from it that isn't there, because it doesn't know
- * whether the content hasn't arrived yet or whether the content has finished.
- * So, one of these, initialized with the Content-length sent in the
- * ServletInputStream's header, will stop it blocking, providing it's been sent
- * with a correct content length.
- *
- * @version $Id$
- * @since Commons IO 2.0
- */
-public class BoundedInputStream extends InputStream {
-
-    /** the wrapped input stream */
-    private final InputStream in;
-
-    /** the max length to provide */
-    private final long max;
-
-    /** the number of bytes already returned */
-    private long pos;
-
-    /** the marked position */
-    private long mark = -1;
-
-    /** flag if close shoud be propagated */
-    private boolean propagateClose = true;
-
-    /**
-     * Creates a new <code>BoundedInputStream</code> that wraps the given input
-     * stream and limits it to a certain size.
-     *
-     * @param in The wrapped input stream
-     * @param size The maximum number of bytes to return
-     */
-    public BoundedInputStream(InputStream in, long size) {
-        // Some badly designed methods - eg the servlet API - overload length
-        // such that "-1" means stream finished
-        this.max = size;
-        this.in = in;
-    }
-
-    /**
-     * Creates a new <code>BoundedInputStream</code> that wraps the given input
-     * stream and is unlimited.
-     *
-     * @param in The wrapped input stream
-     */
-    public BoundedInputStream(InputStream in) {
-        this(in, -1);
-    }
-
-    /**
-     * Invokes the delegate's <code>read()</code> method if
-     * the current position is less than the limit.
-     * @return the byte read or -1 if the end of stream or
-     * the limit has been reached.
-     * @throws IOException if an I/O error occurs
-     */
-    @Override
-    public int read() throws IOException {
-        if (max>=0 && pos==max) {
-            return -1;
-        }
-        int result = in.read();
-        pos++;
-        return result;
-    }
-
-    /**
-     * Invokes the delegate's <code>read(byte[])</code> method.
-     * @param b the buffer to read the bytes into
-     * @return the number of bytes read or -1 if the end of stream or
-     * the limit has been reached.
-     * @throws IOException if an I/O error occurs
-     */
-    @Override
-    public int read(byte[] b) throws IOException {
-        return this.read(b, 0, b.length);
-    }
-
-    /**
-     * Invokes the delegate's <code>read(byte[], int, int)</code> method.
-     * @param b the buffer to read the bytes into
-     * @param off The start offset
-     * @param len The number of bytes to read
-     * @return the number of bytes read or -1 if the end of stream or
-     * the limit has been reached.
-     * @throws IOException if an I/O error occurs
-     */
-    @Override
-    public int read(byte[] b, int off, int len) throws IOException {
-        if (max>=0 && pos>=max) {
-            return -1;
-        }
-        long maxRead = max>=0 ? Math.min(len, max-pos) : len;
-        int bytesRead = in.read(b, off, (int)maxRead);
-
-        if (bytesRead==-1) {
-            return -1;
-        }
-
-        pos+=bytesRead;
-        return bytesRead;
-    }
-
-    /**
-     * Invokes the delegate's <code>skip(long)</code> method.
-     * @param n the number of bytes to skip
-     * @return the actual number of bytes skipped; might be fewer than requested
-     * @throws IOException if an I/O error occurs
-     */
-    @Override
-    public long skip(long n) throws IOException {
-        long toSkip = max>=0 ? Math.min(n, max-pos) : n;
-        long skippedBytes = IOUtils.skipFully(in, toSkip);
-        pos+=skippedBytes;
-        return skippedBytes;
-    }
-
-    /**
-     * {@inheritDoc}
-     */
-    @Override
-    @SuppressForbidden("just delegating")
-    public int available() throws IOException {
-        if (max>=0 && pos>=max) {
-            return 0;
-        }
-        return in.available();
-    }
-
-    /**
-     * Invokes the delegate's <code>toString()</code> method.
-     * @return the delegate's <code>toString()</code>
-     */
-    @Override
-    public String toString() {
-        return in.toString();
-    }
-
-    /**
-     * Invokes the delegate's <code>close()</code> method
-     * if {@link #isPropagateClose()} is <code>true</code>.
-     * @throws IOException if an I/O error occurs
-     */
-    @Override
-    public void close() throws IOException {
-        if (propagateClose) {
-            in.close();
-        }
-    }
-
-    /**
-     * Invokes the delegate's <code>reset()</code> method.
-     * @throws IOException if an I/O error occurs
-     */
-    @Override
-    public synchronized void reset() throws IOException {
-        in.reset();
-        pos = mark;
-    }
-
-    /**
-     * Invokes the delegate's <code>mark(int)</code> method.
-     * @param readlimit read ahead limit
-     */
-    @Override
-    public synchronized void mark(int readlimit) {
-        in.mark(readlimit);
-        mark = pos;
-    }
-
-    /**
-     * Invokes the delegate's <code>markSupported()</code> method.
-     * @return true if mark is supported, otherwise false
-     */
-    @Override
-    public boolean markSupported() {
-        return in.markSupported();
-    }
-
-    /**
-     * Indicates whether the {@link #close()} method
-     * should propagate to the underling {@link InputStream}.
-     *
-     * @return <code>true</code> if calling {@link #close()}
-     * propagates to the <code>close()</code> method of the
-     * underlying stream or <code>false</code> if it does not.
-     */
-    public boolean isPropagateClose() {
-        return propagateClose;
-    }
-
-    /**
-     * Set whether the {@link #close()} method
-     * should propagate to the underling {@link InputStream}.
-     *
-     * @param propagateClose <code>true</code> if calling
-     * {@link #close()} propagates to the <code>close()</code>
-     * method of the underlying stream or
-     * <code>false</code> if it does not.
-     */
-    public void setPropagateClose(boolean propagateClose) {
-        this.propagateClose = propagateClose;
-    }
-}
diff --git a/poi/src/main/java/org/apache/poi/util/GenericRecordJsonWriter.java b/poi/src/main/java/org/apache/poi/util/GenericRecordJsonWriter.java
index c46a535a0b..281b8180b0 100644
--- a/poi/src/main/java/org/apache/poi/util/GenericRecordJsonWriter.java
+++ b/poi/src/main/java/org/apache/poi/util/GenericRecordJsonWriter.java
@@ -19,6 +19,8 @@
 
 package org.apache.poi.util;
 
+import static org.apache.commons.io.output.NullOutputStream.NULL_OUTPUT_STREAM;
+
 import java.awt.Color;
 import java.awt.geom.AffineTransform;
 import java.awt.geom.Dimension2D;
@@ -115,7 +117,7 @@ public class GenericRecordJsonWriter implements Closeable {
     protected int childIndex = 0;
 
     public GenericRecordJsonWriter(File fileName) throws IOException {
-        OutputStream os = ("null".equals(fileName.getName())) ? new NullOutputStream() : new FileOutputStream(fileName);
+        OutputStream os = ("null".equals(fileName.getName())) ? NULL_OUTPUT_STREAM : new FileOutputStream(fileName);
         aw = new AppendableWriter(new OutputStreamWriter(os, StandardCharsets.UTF_8));
         fw = new PrintWriter(aw);
     }
@@ -531,23 +533,6 @@ public class GenericRecordJsonWriter implements Closeable {
         return ZEROS.substring(0, Math.max(0,size-len)) + b.substring(Math.max(0,len-size), len);
     }
 
-    static class NullOutputStream extends OutputStream {
-        NullOutputStream() {
-        }
-
-        @Override
-        public void write(byte[] b, int off, int len) {
-        }
-
-        @Override
-        public void write(int b) {
-        }
-
-        @Override
-        public void write(byte[] b) {
-        }
-    }
-
     static class AppendableWriter extends Writer {
         private final Appendable appender;
         private final Writer writer;
diff --git a/poi/src/main/java/org/apache/poi/util/GenericRecordXmlWriter.java b/poi/src/main/java/org/apache/poi/util/GenericRecordXmlWriter.java
index c5a949cc63..a90f9c94fb 100644
--- a/poi/src/main/java/org/apache/poi/util/GenericRecordXmlWriter.java
+++ b/poi/src/main/java/org/apache/poi/util/GenericRecordXmlWriter.java
@@ -19,6 +19,8 @@
 
 package org.apache.poi.util;
 
+import static org.apache.commons.io.output.NullOutputStream.NULL_OUTPUT_STREAM;
+
 import java.awt.Color;
 import java.awt.geom.AffineTransform;
 import java.awt.geom.Dimension2D;
@@ -50,7 +52,6 @@ import java.util.stream.Stream;
 
 import org.apache.poi.common.usermodel.GenericRecord;
 import org.apache.poi.util.GenericRecordJsonWriter.AppendableWriter;
-import org.apache.poi.util.GenericRecordJsonWriter.NullOutputStream;
 
 @SuppressWarnings("WeakerAccess")
 public class GenericRecordXmlWriter implements Closeable {
@@ -73,7 +74,7 @@ public class GenericRecordXmlWriter implements Closeable {
         boolean print(GenericRecordXmlWriter record, String name, Object object);
     }
 
-    private static final List<Map.Entry<Class, GenericRecordHandler>> handler = new ArrayList<>();
+    private static final List<Map.Entry<Class<?>, GenericRecordHandler>> handler = new ArrayList<>();
 
     static {
         char[] t = new char[255];
@@ -97,7 +98,7 @@ public class GenericRecordXmlWriter implements Closeable {
         handler(Object.class, GenericRecordXmlWriter::printObject);
     }
 
-    private static void handler(Class c, GenericRecordHandler printer) {
+    private static void handler(Class<?> c, GenericRecordHandler printer) {
         handler.add(new AbstractMap.SimpleEntry<>(c, printer));
     }
 
@@ -108,7 +109,7 @@ public class GenericRecordXmlWriter implements Closeable {
     private boolean attributePhase = true;
 
     public GenericRecordXmlWriter(File fileName) throws IOException {
-        OutputStream os = ("null".equals(fileName.getName())) ? new NullOutputStream() : new FileOutputStream(fileName);
+        OutputStream os = ("null".equals(fileName.getName())) ? NULL_OUTPUT_STREAM : new FileOutputStream(fileName);
         fw = new PrintWriter(new OutputStreamWriter(os, StandardCharsets.UTF_8));
     }
 
@@ -150,10 +151,10 @@ public class GenericRecordXmlWriter implements Closeable {
 
     protected void write(final String name, GenericRecord record) {
         final String tabs = tabs();
-        Enum type = record.getGenericRecordType();
+        Enum<?> type = record.getGenericRecordType();
         String recordName = (type != null) ? type.name() : record.getClass().getSimpleName();
         fw.append(tabs);
-        fw.append("<"+name+" type=\"");
+        fw.append("<").append(name).append(" type=\"");
         fw.append(recordName);
         fw.append("\"");
         if (childIndex > 0) {
@@ -279,7 +280,7 @@ public class GenericRecordXmlWriter implements Closeable {
         }
     }
 
-    protected static boolean matchInstanceOrArray(Class key, Object instance) {
+    protected static boolean matchInstanceOrArray(Class<?> key, Object instance) {
         return key.isInstance(instance) || (Array.class.equals(key) && instance.getClass().isArray());
     }
 
@@ -332,8 +333,7 @@ public class GenericRecordXmlWriter implements Closeable {
         openName(name+">");
         int oldChildIndex = childIndex;
         childIndex = 0;
-        //noinspection unchecked
-        ((List)o).forEach(e -> { writeValue("item>", e); childIndex++; });
+        ((List<?>)o).forEach(e -> { writeValue("item>", e); childIndex++; });
         childIndex = oldChildIndex;
         closeName(name+">");
         return true;
@@ -478,7 +478,7 @@ public class GenericRecordXmlWriter implements Closeable {
                 case "&":
                     fw.write("&amp;");
                     break;
-                case "\'":
+                case "'":
                     fw.write("&apos;");
                     break;
                 case "\"":
diff --git a/poi/src/main/java/org/apache/poi/util/IOUtils.java b/poi/src/main/java/org/apache/poi/util/IOUtils.java
index ec348b67a2..279b56974c 100644
--- a/poi/src/main/java/org/apache/poi/util/IOUtils.java
+++ b/poi/src/main/java/org/apache/poi/util/IOUtils.java
@@ -17,7 +17,6 @@
 
 package org.apache.poi.util;
 
-import java.io.ByteArrayOutputStream;
 import java.io.Closeable;
 import java.io.EOFException;
 import java.io.File;
@@ -33,6 +32,8 @@ import java.util.Locale;
 import java.util.zip.CRC32;
 import java.util.zip.Checksum;
 
+import org.apache.commons.io.input.BoundedInputStream;
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.poi.EmptyFileException;
@@ -106,7 +107,7 @@ public final class IOUtils {
         checkByteSizeLimit(limit);
 
         stream.mark(limit);
-        ByteArrayOutputStream bos = new ByteArrayOutputStream(limit);
+        UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream(limit);
         copy(new BoundedInputStream(stream, limit), bos);
 
         int readBytes = bos.size();
@@ -177,7 +178,7 @@ public final class IOUtils {
         }
 
         final int len = Math.min(length, maxLength);
-        ByteArrayOutputStream baos = new ByteArrayOutputStream(len == Integer.MAX_VALUE ? 4096 : len);
+        UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream(len == Integer.MAX_VALUE ? 4096 : len);
 
         byte[] buffer = new byte[4096];
         int totalBytes = 0, readBytes;
diff --git a/poi/src/main/java/org/apache/poi/util/LZWDecompresser.java b/poi/src/main/java/org/apache/poi/util/LZWDecompresser.java
index 0ebae8a0ac..1a0052e08b 100644
--- a/poi/src/main/java/org/apache/poi/util/LZWDecompresser.java
+++ b/poi/src/main/java/org/apache/poi/util/LZWDecompresser.java
@@ -16,11 +16,12 @@
 ==================================================================== */
 package org.apache.poi.util;
 
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
+
 /**
  * This class provides common functionality for the
  * various LZW implementations in the different file
@@ -86,7 +87,7 @@ public abstract class LZWDecompresser {
      * of the decompressed input.
      */
     public byte[] decompress(InputStream src) throws IOException {
-        ByteArrayOutputStream res = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream res = new UnsynchronizedByteArrayOutputStream();
         decompress(src, res);
         return res.toByteArray();
     }
diff --git a/poi/src/main/java/org/apache/poi/util/RLEDecompressingInputStream.java b/poi/src/main/java/org/apache/poi/util/RLEDecompressingInputStream.java
index 6bd7fef86e..aa2211eb1a 100644
--- a/poi/src/main/java/org/apache/poi/util/RLEDecompressingInputStream.java
+++ b/poi/src/main/java/org/apache/poi/util/RLEDecompressingInputStream.java
@@ -18,11 +18,12 @@
 package org.apache.poi.util;
 
 import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.util.Locale;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
+
 /**
  * Wrapper of InputStream which provides Run Length Encoding (RLE)
  *  decompression on the fly. Uses MS-OVBA decompression algorithm. See
@@ -68,7 +69,6 @@ public class RLEDecompressingInputStream extends InputStream {
      * Creates a new wrapper RLE Decompression InputStream.
      *
      * @param in The stream to wrap with the RLE Decompression
-     * @throws IOException
      */
     public RLEDecompressingInputStream(InputStream in) throws IOException {
         this.in = in;
@@ -152,7 +152,6 @@ public class RLEDecompressingInputStream extends InputStream {
      * Reads a single chunk from the underlying inputstream.
      *
      * @return number of bytes that were read, or -1 if the end of the stream was reached.
-     * @throws IOException
      */
     private int readChunk() throws IOException {
         pos = 0;
@@ -216,7 +215,6 @@ public class RLEDecompressingInputStream extends InputStream {
     /**
      * Helper method to determine how many bits in the CopyToken are used for the CopyLength.
      *
-     * @param offset
      * @return returns the number of bits in the copy token (a value between 4 and 12)
      */
     static int getCopyLenBits(int offset) {
@@ -232,7 +230,6 @@ public class RLEDecompressingInputStream extends InputStream {
      * Convenience method for read a 2-bytes short in little endian encoding.
      *
      * @return short value from the stream, -1 if end of stream is reached
-     * @throws IOException
      */
     public int readShort() throws IOException {
         return readShort(this);
@@ -242,7 +239,6 @@ public class RLEDecompressingInputStream extends InputStream {
      * Convenience method for read a 4-bytes int in little endian encoding.
      *
      * @return integer value from the stream, -1 if end of stream is reached
-     * @throws IOException
      */
     public int readInt() throws IOException {
         return readInt(this);
@@ -281,12 +277,12 @@ public class RLEDecompressingInputStream extends InputStream {
     }
 
     public static byte[] decompress(byte[] compressed, int offset, int length) throws IOException {
-        ByteArrayOutputStream out = new ByteArrayOutputStream();
-        InputStream instream = new ByteArrayInputStream(compressed, offset, length);
-        InputStream stream = new RLEDecompressingInputStream(instream);
-        IOUtils.copy(stream, out);
-        stream.close();
-        out.close();
-        return out.toByteArray();
+        try (UnsynchronizedByteArrayOutputStream out = new UnsynchronizedByteArrayOutputStream();
+            InputStream instream = new ByteArrayInputStream(compressed, offset, length);
+            InputStream stream = new RLEDecompressingInputStream(instream)) {
+
+            IOUtils.copy(stream, out);
+            return out.toByteArray();
+        }
     }
 }
diff --git a/poi/src/test/java/org/apache/poi/POIDataSamples.java b/poi/src/test/java/org/apache/poi/POIDataSamples.java
index 0772017d0a..dc9066c1bc 100644
--- a/poi/src/test/java/org/apache/poi/POIDataSamples.java
+++ b/poi/src/test/java/org/apache/poi/POIDataSamples.java
@@ -16,13 +16,16 @@
 ==================================================================== */
 package org.apache.poi;
 
-import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.io.InputStream;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
+import org.apache.poi.poifs.filesystem.POIFSFileSystem;
+import org.apache.poi.util.IOUtils;
+
 /**
  * Centralises logic for finding/opening sample files
  */
@@ -47,7 +50,7 @@ public final class POIDataSamples {
     private static POIDataSamples _instXmlDSign;
 
     private File _resolvedDataDir;
-    /** {@code true} if standard system propery is not set,
+    /** {@code true} if standard system property is not set,
      * but the data is available on the test runtime classpath */
     private boolean _sampleDataIsAvaliableOnClassPath;
     private final String _moduleDir;
@@ -260,24 +263,19 @@ public final class POIDataSamples {
      * @return byte array of sample file content from file found in standard test-data directory
      */
     public byte[] readFile(String fileName) {
-        ByteArrayOutputStream bos = new ByteArrayOutputStream();
-
-        try {
-            InputStream fis = openResourceAsStream(fileName);
-
-            byte[] buf = new byte[512];
-            while (true) {
-                int bytesRead = fis.read(buf);
-                if (bytesRead < 1) {
-                    break;
-                }
-                bos.write(buf, 0, bytesRead);
-            }
-            fis.close();
+        try (InputStream fis = openResourceAsStream(fileName);
+             UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream()) {
+            IOUtils.copy(fis, bos);
+            return bos.toByteArray();
         } catch (IOException e) {
             throw new RuntimeException(e);
         }
-        return bos.toByteArray();
     }
 
+    public static POIFSFileSystem writeOutAndReadBack(POIFSFileSystem original) throws IOException {
+        try (UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream()) {
+            original.writeFilesystem(baos);
+            return new POIFSFileSystem(baos.toInputStream());
+        }
+    }
 }
diff --git a/poi/src/test/java/org/apache/poi/TestPOIDocumentMain.java b/poi/src/test/java/org/apache/poi/TestPOIDocumentMain.java
index c2c44529b8..78fd9db41b 100644
--- a/poi/src/test/java/org/apache/poi/TestPOIDocumentMain.java
+++ b/poi/src/test/java/org/apache/poi/TestPOIDocumentMain.java
@@ -17,21 +17,20 @@
 
 package org.apache.poi;
 
+import static org.apache.poi.hssf.HSSFTestDataSamples.openSampleWorkbook;
+import static org.apache.poi.hssf.HSSFTestDataSamples.writeOutAndReadBack;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertNull;
 
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.hpsf.DocumentSummaryInformation;
 import org.apache.poi.hpsf.HPSFPropertiesOnlyDocument;
 import org.apache.poi.hpsf.SummaryInformation;
-import org.apache.poi.hssf.HSSFTestDataSamples;
 import org.apache.poi.hssf.usermodel.HSSFWorkbook;
 import org.apache.poi.poifs.filesystem.POIFSFileSystem;
-import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
 /**
@@ -42,22 +41,11 @@ import org.junit.jupiter.api.Test;
  *  which are part of the Main (not scratchpad)
  */
 final class TestPOIDocumentMain {
-    // The POI Documents to work on
-    private POIDocument doc;
-    private POIDocument doc2;
-
-    /**
-     * Set things up, two spreadsheets for our testing
-     */
-    @BeforeEach
-    void setUp() {
-        doc = HSSFTestDataSamples.openSampleWorkbook("DateFormats.xls");
-        doc2 = HSSFTestDataSamples.openSampleWorkbook("StringFormulas.xls");
-    }
-
     @Test
-    void readProperties() {
-        readPropertiesHelper(doc);
+    void readProperties() throws IOException {
+        try (POIDocument xls = openSampleWorkbook("DateFormats.xls")) {
+            readPropertiesHelper(xls);
+        }
     }
 
     private void readPropertiesHelper(POIDocument docWB) {
@@ -71,130 +59,108 @@ final class TestPOIDocumentMain {
     }
 
     @Test
-    void readProperties2() {
-        // Check again on the word one
-        assertNotNull(doc2.getDocumentSummaryInformation());
-        assertNotNull(doc2.getSummaryInformation());
-
-        assertEquals("Avik Sengupta", doc2.getSummaryInformation().getAuthor());
-        assertNull(doc2.getSummaryInformation().getKeywords());
-        assertEquals(0, doc2.getDocumentSummaryInformation().getByteCount());
+    void readProperties2() throws IOException {
+        try (POIDocument xls = openSampleWorkbook("StringFormulas.xls")) {
+            // Check again on the word one
+            assertNotNull(xls.getDocumentSummaryInformation());
+            assertNotNull(xls.getSummaryInformation());
+
+            assertEquals("Avik Sengupta", xls.getSummaryInformation().getAuthor());
+            assertNull(xls.getSummaryInformation().getKeywords());
+            assertEquals(0, xls.getDocumentSummaryInformation().getByteCount());
+        }
     }
 
     @Test
     void writeProperties() throws IOException {
         // Just check we can write them back out into a filesystem
-        POIFSFileSystem outFS = new POIFSFileSystem();
-        doc.readProperties();
-        doc.writeProperties(outFS);
-
-        // Should now hold them
-        assertNotNull(
-                outFS.createDocumentInputStream(SummaryInformation.DEFAULT_STREAM_NAME)
-        );
-        assertNotNull(
-                outFS.createDocumentInputStream(DocumentSummaryInformation.DEFAULT_STREAM_NAME)
-        );
+        try (POIDocument xls = openSampleWorkbook("DateFormats.xls");
+             POIFSFileSystem outFS = new POIFSFileSystem()) {
+            xls.readProperties();
+            xls.writeProperties(outFS);
+
+            // Should now hold them
+            assertNotNull(outFS.createDocumentInputStream(SummaryInformation.DEFAULT_STREAM_NAME));
+            assertNotNull(outFS.createDocumentInputStream(DocumentSummaryInformation.DEFAULT_STREAM_NAME));
+        }
     }
 
     @Test
     void WriteReadProperties() throws IOException {
-        ByteArrayOutputStream baos = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
 
         // Write them out
-        POIFSFileSystem outFS = new POIFSFileSystem();
-        doc.readProperties();
-        doc.writeProperties(outFS);
-        outFS.writeFilesystem(baos);
+        try (POIDocument xls = openSampleWorkbook("DateFormats.xls");
+             POIFSFileSystem outFS = new POIFSFileSystem()) {
+            xls.readProperties();
+            xls.writeProperties(outFS);
+            outFS.writeFilesystem(baos);
+        }
 
         // Create a new version
-        ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
-        POIFSFileSystem inFS = new POIFSFileSystem(bais);
+        try (POIFSFileSystem inFS = new POIFSFileSystem(baos.toInputStream());
+             POIDocument doc3 = new HPSFPropertiesOnlyDocument(inFS)) {
 
-        // Check they're still there
-        POIDocument doc3 = new HPSFPropertiesOnlyDocument(inFS);
-        doc3.readProperties();
+            // Check they're still there
+            doc3.readProperties();
 
-        // Delegate test
-        readPropertiesHelper(doc3);
-        doc3.close();
+            // Delegate test
+            readPropertiesHelper(doc3);
+        }
     }
 
     @Test
     void createNewProperties() throws IOException {
-        POIDocument doc = new HSSFWorkbook();
-
-        // New document won't have them
-        assertNull(doc.getSummaryInformation());
-        assertNull(doc.getDocumentSummaryInformation());
-
-        // Add them in
-        doc.createInformationProperties();
-        assertNotNull(doc.getSummaryInformation());
-        assertNotNull(doc.getDocumentSummaryInformation());
-
-        // Write out and back in again, no change
-        ByteArrayOutputStream baos = new ByteArrayOutputStream();
-        doc.write(baos);
-        ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
+        try (HSSFWorkbook xls1 = new HSSFWorkbook()) {
+            // New document won't have them
+            assertNull(xls1.getSummaryInformation());
+            assertNull(xls1.getDocumentSummaryInformation());
+
+            // Add them in
+            xls1.createInformationProperties();
+            assertNotNull(xls1.getSummaryInformation());
+            assertNotNull(xls1.getDocumentSummaryInformation());
+
+            try (HSSFWorkbook xls2 = writeOutAndReadBack(xls1)) {
+                assertNotNull(xls2.getSummaryInformation());
+                assertNotNull(xls2.getDocumentSummaryInformation());
+            }
+        }
 
-        doc.close();
-
-        doc = new HSSFWorkbook(bais);
-
-        assertNotNull(doc.getSummaryInformation());
-        assertNotNull(doc.getDocumentSummaryInformation());
-
-        doc.close();
     }
 
     @Test
     void createNewPropertiesOnExistingFile() throws IOException {
-        POIDocument doc = new HSSFWorkbook();
-
-        // New document won't have them
-        assertNull(doc.getSummaryInformation());
-        assertNull(doc.getDocumentSummaryInformation());
-
-        // Write out and back in again, no change
-        ByteArrayOutputStream baos = new ByteArrayOutputStream();
-        doc.write(baos);
-
-        doc.close();
-
-        ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
-        doc = new HSSFWorkbook(bais);
-
-        assertNull(doc.getSummaryInformation());
-        assertNull(doc.getDocumentSummaryInformation());
-
-        // Create, and change
-        doc.createInformationProperties();
-        doc.getSummaryInformation().setAuthor("POI Testing");
-        doc.getDocumentSummaryInformation().setCompany("ASF");
-
-        // Save and re-load
-        baos = new ByteArrayOutputStream();
-        doc.write(baos);
-
-        doc.close();
-
-        bais = new ByteArrayInputStream(baos.toByteArray());
-        doc = new HSSFWorkbook(bais);
-
-        // Check
-        assertNotNull(doc.getSummaryInformation());
-        assertNotNull(doc.getDocumentSummaryInformation());
-        assertEquals("POI Testing", doc.getSummaryInformation().getAuthor());
-        assertEquals("ASF", doc.getDocumentSummaryInformation().getCompany());
-
-        // Asking to re-create will make no difference now
-        doc.createInformationProperties();
-        assertNotNull(doc.getSummaryInformation());
-        assertNotNull(doc.getDocumentSummaryInformation());
-        assertEquals("POI Testing", doc.getSummaryInformation().getAuthor());
-        assertEquals("ASF", doc.getDocumentSummaryInformation().getCompany());
-
-        doc.close();
+        try (HSSFWorkbook xls1 = new HSSFWorkbook()) {
+            // New document won't have them
+            assertNull(xls1.getSummaryInformation());
+            assertNull(xls1.getDocumentSummaryInformation());
+
+            try (HSSFWorkbook xls2 = writeOutAndReadBack(xls1)) {
+
+                assertNull(xls2.getSummaryInformation());
+                assertNull(xls2.getDocumentSummaryInformation());
+
+                // Create, and change
+                xls2.createInformationProperties();
+                xls2.getSummaryInformation().setAuthor("POI Testing");
+                xls2.getDocumentSummaryInformation().setCompany("ASF");
+
+                try (HSSFWorkbook xls3 = writeOutAndReadBack(xls2)) {
+                    // Check
+                    assertNotNull(xls3.getSummaryInformation());
+                    assertNotNull(xls3.getDocumentSummaryInformation());
+                    assertEquals("POI Testing", xls3.getSummaryInformation().getAuthor());
+                    assertEquals("ASF", xls3.getDocumentSummaryInformation().getCompany());
+
+                    // Asking to re-create will make no difference now
+                    xls3.createInformationProperties();
+                    assertNotNull(xls3.getSummaryInformation());
+                    assertNotNull(xls3.getDocumentSummaryInformation());
+                    assertEquals("POI Testing", xls3.getSummaryInformation().getAuthor());
+                    assertEquals("ASF", xls3.getDocumentSummaryInformation().getCompany());
+                }
+            }
+        }
     }
 }
diff --git a/poi/src/test/java/org/apache/poi/ddf/TestEscherBlipRecord.java b/poi/src/test/java/org/apache/poi/ddf/TestEscherBlipRecord.java
index a081f61c65..3130b6b9b2 100644
--- a/poi/src/test/java/org/apache/poi/ddf/TestEscherBlipRecord.java
+++ b/poi/src/test/java/org/apache/poi/ddf/TestEscherBlipRecord.java
@@ -17,6 +17,7 @@
 
 package org.apache.poi.ddf;
 
+import static org.apache.poi.ddf.EscherRecordTypes.BLIP_PICT;
 import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
@@ -100,7 +101,7 @@ final class TestEscherBlipRecord {
 
         EscherMetafileBlip blip1 = (EscherMetafileBlip)bse1.getBlipRecord();
         assertEquals(0x5430, blip1.getOptions());
-        assertEquals(EscherMetafileBlip.RECORD_ID_PICT, blip1.getRecordId());
+        assertEquals(BLIP_PICT.typeID, blip1.getRecordId());
         assertArrayEquals(new byte[]{
             0x57, 0x32, 0x7B, (byte)0x91, 0x23, 0x5D, (byte)0xDB, 0x36,
             0x7A, (byte)0xDB, (byte)0xFF, 0x17, (byte)0xFE, (byte)0xF3, (byte)0xA7, 0x05
@@ -151,11 +152,13 @@ final class TestEscherBlipRecord {
         byte[] data = _samples.readFile("47143.dat");
         EscherBSERecord bse = new EscherBSERecord();
         bse.fillFields(data, 0, new DefaultEscherRecordFactory());
-        bse.toString(); //assert that toString() works
+        //assert that toString() works
+        assertNotNull(bse.toString());
         assertTrue(bse.getBlipRecord() instanceof EscherMetafileBlip);
 
         EscherMetafileBlip blip = (EscherMetafileBlip)bse.getBlipRecord();
-        blip.toString(); //assert that toString() works
+        //assert that toString() works
+        assertNotNull(blip.toString());
         byte[] remaining = blip.getRemainingData();
         assertNotNull(remaining);
 
diff --git a/poi/src/test/java/org/apache/poi/ddf/TestEscherDump.java b/poi/src/test/java/org/apache/poi/ddf/TestEscherDump.java
index 088d346bae..07c67c4c10 100644
--- a/poi/src/test/java/org/apache/poi/ddf/TestEscherDump.java
+++ b/poi/src/test/java/org/apache/poi/ddf/TestEscherDump.java
@@ -21,7 +21,6 @@ import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotEquals;
 
-import java.io.ByteArrayOutputStream;
 import java.io.InputStream;
 import java.io.PrintStream;
 import java.io.UnsupportedEncodingException;
@@ -29,6 +28,7 @@ import java.nio.charset.StandardCharsets;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.POIDataSamples;
 import org.apache.poi.hssf.HSSFTestDataSamples;
 import org.apache.poi.poifs.storage.RawDataUtil;
@@ -63,8 +63,8 @@ class TestEscherDump {
         "cT19LR+PfTgjN4CKCS5Es4LS+7nLt9hQ7ejwGQnEyxebOgJzlHjotWUACpoZsFkAgGqBeUDZAzB6h4N2MFCNhmIuFJMAgPsH" +
         "eJr+iZEHAAA=";
 
-    private EscherDump dumper = new EscherDump();
-    private ByteArrayOutputStream baos = new ByteArrayOutputStream();
+    private final EscherDump dumper = new EscherDump();
+    private final UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
     private PrintStream stream;
 
     @BeforeEach
@@ -126,7 +126,7 @@ class TestEscherDump {
     }
 
     private int countProperties() {
-        String data = new String(baos.toByteArray(), StandardCharsets.UTF_8);
+        String data = baos.toString(StandardCharsets.UTF_8);
         Matcher matcher = Pattern.compile(",? \"[^\"]+\": ").matcher(data);
         int count = 0;
         while (matcher.find()) {
diff --git a/poi/src/test/java/org/apache/poi/hpsf/TestVariantSupport.java b/poi/src/test/java/org/apache/poi/hpsf/TestVariantSupport.java
index 1cea118353..c3932c3b0a 100644
--- a/poi/src/test/java/org/apache/poi/hpsf/TestVariantSupport.java
+++ b/poi/src/test/java/org/apache/poi/hpsf/TestVariantSupport.java
@@ -21,11 +21,12 @@ package org.apache.poi.hpsf;
 import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertSame;
 
 import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.math.BigInteger;
 
+import org.apache.poi.POIDataSamples;
 import org.apache.poi.hpsf.wellknown.PropertyIDMap;
 import org.apache.poi.poifs.filesystem.POIFSFileSystem;
 import org.apache.poi.poifs.storage.RawDataUtil;
@@ -51,7 +52,7 @@ class TestVariantSupport {
 
         Object hdrs =  s.getProperty(PropertyIDMap.PID_HEADINGPAIR);
         assertNotNull(hdrs);
-        assertEquals(byte[].class, hdrs.getClass());
+        assertSame(byte[].class, hdrs.getClass());
 
         // parse the value
         Vector v = new Vector((short)Variant.VT_VARIANT);
@@ -63,10 +64,10 @@ class TestVariantSupport {
 
         Object cp = items[0].getValue();
         assertNotNull(cp);
-        assertEquals(CodePageString.class, cp.getClass());
+        assertSame(CodePageString.class, cp.getClass());
         Object i = items[1].getValue();
         assertNotNull(i);
-        assertEquals(Integer.class, i.getClass());
+        assertSame(Integer.class, i.getClass());
         assertEquals(1, i);
 
     }
@@ -91,34 +92,33 @@ class TestVariantSupport {
                 {Variant.VT_R8, -999.99d},
         };
 
-        POIFSFileSystem poifs = new POIFSFileSystem();
-        DocumentSummaryInformation dsi = PropertySetFactory.newDocumentSummaryInformation();
-        CustomProperties cpList = new CustomProperties();
-        for (Object[] o : exp) {
-            int type = (Integer)o[0];
-            Property p = new Property(PropertyIDMap.PID_MAX+type, type, o[1]);
-            cpList.put("testprop"+type, new CustomProperty(p, "testprop"+type));
+        try (POIFSFileSystem poifs = new POIFSFileSystem()) {
+            DocumentSummaryInformation dsi = PropertySetFactory.newDocumentSummaryInformation();
+            CustomProperties cpList = new CustomProperties();
+            for (Object[] o : exp) {
+                int type = (Integer) o[0];
+                Property p = new Property(PropertyIDMap.PID_MAX + type, type, o[1]);
+                cpList.put("testprop" + type, new CustomProperty(p, "testprop" + type));
 
-        }
-        dsi.setCustomProperties(cpList);
-        dsi.write(poifs.getRoot(), DocumentSummaryInformation.DEFAULT_STREAM_NAME);
-        ByteArrayOutputStream bos = new ByteArrayOutputStream();
-        poifs.writeFilesystem(bos);
-        poifs.close();
-        poifs = new POIFSFileSystem(new ByteArrayInputStream(bos.toByteArray()));
-        dsi = (DocumentSummaryInformation)PropertySetFactory.create(poifs.getRoot(), DocumentSummaryInformation.DEFAULT_STREAM_NAME);
-        assertNotNull(dsi);
-        cpList = dsi.getCustomProperties();
-        int i=0;
-        for (Object[] o : exp) {
-            Object obj = cpList.get("testprop"+o[0]);
-            if (o[1] instanceof byte[]) {
-                assertArrayEquals((byte[])o[1], (byte[])obj, "property "+i);
-            } else {
-                assertEquals(o[1], obj, "property "+i);
             }
-            i++;
+            dsi.setCustomProperties(cpList);
+            dsi.write(poifs.getRoot(), DocumentSummaryInformation.DEFAULT_STREAM_NAME);
+
+            try (POIFSFileSystem poifs2 = POIDataSamples.writeOutAndReadBack(poifs)) {
+                DocumentSummaryInformation dsi2 = (DocumentSummaryInformation) PropertySetFactory.create(poifs2.getRoot(), DocumentSummaryInformation.DEFAULT_STREAM_NAME);
+                assertNotNull(dsi2);
+                CustomProperties cpList2 = dsi2.getCustomProperties();
+                int i = 0;
+                for (Object[] o : exp) {
+                    Object obj = cpList2.get("testprop" + o[0]);
+                    if (o[1] instanceof byte[]) {
+                        assertArrayEquals((byte[]) o[1], (byte[]) obj, "property " + i);
+                    } else {
+                        assertEquals(o[1], obj, "property " + i);
+                    }
+                    i++;
+                }
+            }
         }
-        poifs.close();
     }
 }
diff --git a/poi/src/test/java/org/apache/poi/hpsf/basic/TestBasic.java b/poi/src/test/java/org/apache/poi/hpsf/basic/TestBasic.java
index 6d95b38450..cc75abc874 100644
--- a/poi/src/test/java/org/apache/poi/hpsf/basic/TestBasic.java
+++ b/poi/src/test/java/org/apache/poi/hpsf/basic/TestBasic.java
@@ -19,6 +19,7 @@ package org.apache.poi.hpsf.basic;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertSame;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.io.ByteArrayInputStream;
@@ -35,7 +36,6 @@ import org.apache.poi.hpsf.ClassID;
 import org.apache.poi.hpsf.DocumentSummaryInformation;
 import org.apache.poi.hpsf.Filetime;
 import org.apache.poi.hpsf.HPSFException;
-import org.apache.poi.hpsf.MarkUnsupportedException;
 import org.apache.poi.hpsf.NoPropertySetStreamException;
 import org.apache.poi.hpsf.PropertySet;
 import org.apache.poi.hpsf.PropertySetFactory;
@@ -109,8 +109,7 @@ final class TestBasic {
      * supported.
      */
     @Test
-    void testCreatePropertySets()
-    throws UnsupportedEncodingException, IOException {
+    void testCreatePropertySets() throws IOException {
         Class<?>[] expected = {
             SummaryInformation.class,
             DocumentSummaryInformation.class,
@@ -123,11 +122,11 @@ final class TestBasic {
             Object o;
             try {
                 o = PropertySetFactory.create(in);
-            } catch (NoPropertySetStreamException | MarkUnsupportedException ex) {
+            } catch (NoPropertySetStreamException ex) {
                 o = ex;
             }
             in.close();
-            assertEquals(expected[i], o.getClass());
+            assertSame(expected[i], o.getClass());
         }
     }
 
diff --git a/poi/src/test/java/org/apache/poi/hpsf/basic/TestEmptyProperties.java b/poi/src/test/java/org/apache/poi/hpsf/basic/TestEmptyProperties.java
index 9ef1289461..300f6f245a 100644
--- a/poi/src/test/java/org/apache/poi/hpsf/basic/TestEmptyProperties.java
+++ b/poi/src/test/java/org/apache/poi/hpsf/basic/TestEmptyProperties.java
@@ -20,6 +20,7 @@ package org.apache.poi.hpsf.basic;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertSame;
 
 import java.io.ByteArrayInputStream;
 import java.io.File;
@@ -32,7 +33,6 @@ import java.util.List;
 import org.apache.poi.POIDataSamples;
 import org.apache.poi.hpsf.DocumentSummaryInformation;
 import org.apache.poi.hpsf.HPSFException;
-import org.apache.poi.hpsf.MarkUnsupportedException;
 import org.apache.poi.hpsf.NoPropertySetStreamException;
 import org.apache.poi.hpsf.PropertySet;
 import org.apache.poi.hpsf.PropertySetFactory;
@@ -101,8 +101,7 @@ final class TestEmptyProperties {
      * supported.
      */
     @Test
-    void testCreatePropertySets()
-    throws UnsupportedEncodingException, IOException {
+    void testCreatePropertySets() throws IOException {
         Class<?>[] expected =  {
             NoPropertySetStreamException.class,
             SummaryInformation.class,
@@ -113,11 +112,11 @@ final class TestEmptyProperties {
             Object o;
             try {
                 o = PropertySetFactory.create(in);
-            } catch (NoPropertySetStreamException | MarkUnsupportedException ex) {
+            } catch (NoPropertySetStreamException ex) {
                 o = ex;
             }
             in.close();
-            assertEquals(o.getClass(), expected[i]);
+            assertSame(o.getClass(), expected[i]);
         }
     }
 
diff --git a/poi/src/test/java/org/apache/poi/hpsf/basic/TestHPSFBugs.java b/poi/src/test/java/org/apache/poi/hpsf/basic/TestHPSFBugs.java
index 6205713fa3..001fc2b238 100644
--- a/poi/src/test/java/org/apache/poi/hpsf/basic/TestHPSFBugs.java
+++ b/poi/src/test/java/org/apache/poi/hpsf/basic/TestHPSFBugs.java
@@ -21,17 +21,15 @@ import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertNull;
 
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.util.Date;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.POIDataSamples;
 import org.apache.poi.POIDocument;
 import org.apache.poi.hpsf.DocumentSummaryInformation;
 import org.apache.poi.hpsf.HPSFPropertiesOnlyDocument;
-import org.apache.poi.hpsf.MarkUnsupportedException;
 import org.apache.poi.hpsf.NoPropertySetStreamException;
 import org.apache.poi.hpsf.PropertySetFactory;
 import org.apache.poi.hpsf.SummaryInformation;
@@ -112,38 +110,37 @@ final class TestHPSFBugs {
     * reading junk
     */
    @Test
-   void test54233() throws IOException, NoPropertySetStreamException, MarkUnsupportedException {
-       InputStream is = _samples.openResourceAsStream("TestNon4ByteBoundary.doc");
-       POIFSFileSystem fs = new POIFSFileSystem(is);
-       is.close();
-
-       SummaryInformation si = (SummaryInformation)
-           PropertySetFactory.create(fs.getRoot(), SummaryInformation.DEFAULT_STREAM_NAME);
-       DocumentSummaryInformation dsi = (DocumentSummaryInformation)
-           PropertySetFactory.create(fs.getRoot(), DocumentSummaryInformation.DEFAULT_STREAM_NAME);
-
-       // Test
-       assertEquals("Microsoft Word 10.0", si.getApplicationName());
-       assertEquals("", si.getTitle());
-       assertEquals("", si.getAuthor());
-       assertEquals("Cour de Justice", dsi.getCompany());
-
-
-       // Write out and read back, should still be valid
-       POIDocument doc = new HPSFPropertiesOnlyDocument(fs);
-       ByteArrayOutputStream baos = new ByteArrayOutputStream();
-       doc.write(baos);
-       ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
-       doc = new HPSFPropertiesOnlyDocument(new POIFSFileSystem(bais));
-
-       // Check properties are still there
-       assertEquals("Microsoft Word 10.0", si.getApplicationName());
-       assertEquals("", si.getTitle());
-       assertEquals("", si.getAuthor());
-       assertEquals("Cour de Justice", dsi.getCompany());
-
-       doc.close();
-       fs.close();
+   void test54233() throws IOException, NoPropertySetStreamException {
+       try (InputStream is = _samples.openResourceAsStream("TestNon4ByteBoundary.doc");
+        POIFSFileSystem fs = new POIFSFileSystem(is)) {
+
+           SummaryInformation si = (SummaryInformation)
+               PropertySetFactory.create(fs.getRoot(), SummaryInformation.DEFAULT_STREAM_NAME);
+           DocumentSummaryInformation dsi = (DocumentSummaryInformation)
+               PropertySetFactory.create(fs.getRoot(), DocumentSummaryInformation.DEFAULT_STREAM_NAME);
+
+           // Test
+           assertEquals("Microsoft Word 10.0", si.getApplicationName());
+           assertEquals("", si.getTitle());
+           assertEquals("", si.getAuthor());
+           assertEquals("Cour de Justice", dsi.getCompany());
+
+
+           // Write out and read back, should still be valid
+           UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
+           try (POIDocument doc = new HPSFPropertiesOnlyDocument(fs)) {
+               doc.write(baos);
+           }
+           try (POIDocument doc = new HPSFPropertiesOnlyDocument(new POIFSFileSystem(baos.toInputStream()))) {
+               si = doc.getSummaryInformation();
+               dsi = doc.getDocumentSummaryInformation();
+               // Check properties are still there
+               assertEquals("Microsoft Word 10.0", si.getApplicationName());
+               assertEquals("", si.getTitle());
+               assertEquals("", si.getAuthor());
+               assertEquals("Cour de Justice", dsi.getCompany());
+           }
+       }
    }
 
    /**
diff --git a/poi/src/test/java/org/apache/poi/hpsf/basic/TestMetaDataIPI.java b/poi/src/test/java/org/apache/poi/hpsf/basic/TestMetaDataIPI.java
index f8fb0aad13..999d0a608b 100644
--- a/poi/src/test/java/org/apache/poi/hpsf/basic/TestMetaDataIPI.java
+++ b/poi/src/test/java/org/apache/poi/hpsf/basic/TestMetaDataIPI.java
@@ -23,13 +23,12 @@ import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertNull;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.util.Date;
 import java.util.Random;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.hpsf.CustomProperties;
 import org.apache.poi.hpsf.DocumentSummaryInformation;
 import org.apache.poi.hpsf.HPSFException;
@@ -44,7 +43,7 @@ import org.junit.jupiter.api.Test;
 /**
  * Basing on: src/examples/src/org/apache/poi/hpsf/examples/ModifyDocumentSummaryInformation.java
  * This class tests reading and writing of meta data. No actual document is created. All information
- * is stored in a virtual document in a ByteArrayOutputStream
+ * is stored in a virtual document in a UnsynchronizedByteArrayOutputStream
  */
 final class TestMetaDataIPI {
 
@@ -520,7 +519,7 @@ final class TestMetaDataIPI {
 
 
     /**
-     * Closes the ByteArrayOutputStream and reads it into a ByteArrayInputStream.
+     * Closes the UnsynchronizedByteArrayOutputStream and reads it into a ByteArrayInputStream.
      * When finished writing information this method is used in the tests to
      * start reading from the created document and then the see if the results match.
      */
@@ -528,13 +527,13 @@ final class TestMetaDataIPI {
         dsi.write(poifs.getRoot(), DocumentSummaryInformation.DEFAULT_STREAM_NAME);
         si.write(poifs.getRoot(), SummaryInformation.DEFAULT_STREAM_NAME);
 
-        ByteArrayOutputStream bout = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream bout = new UnsynchronizedByteArrayOutputStream();
         poifs.writeFilesystem(bout);
         poifs.close();
 
-        InputStream is = new ByteArrayInputStream(bout.toByteArray());
-        poifs = new POIFSFileSystem(is);
-        is.close();
+        try (InputStream is = bout.toInputStream()) {
+			poifs = new POIFSFileSystem(is);
+		}
 
         /* Read the document summary information. */
         DirectoryEntry dir = poifs.getRoot();
diff --git a/poi/src/test/java/org/apache/poi/hpsf/basic/TestReadAllFiles.java b/poi/src/test/java/org/apache/poi/hpsf/basic/TestReadAllFiles.java
index 13eb537fe2..057e16ae87 100644
--- a/poi/src/test/java/org/apache/poi/hpsf/basic/TestReadAllFiles.java
+++ b/poi/src/test/java/org/apache/poi/hpsf/basic/TestReadAllFiles.java
@@ -21,7 +21,6 @@ import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 
 import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
@@ -31,12 +30,12 @@ import java.util.Map;
 import java.util.Objects;
 import java.util.stream.Stream;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.POIDataSamples;
 import org.apache.poi.hpsf.CustomProperties;
 import org.apache.poi.hpsf.CustomProperty;
 import org.apache.poi.hpsf.DocumentSummaryInformation;
 import org.apache.poi.hpsf.HPSFException;
-import org.apache.poi.hpsf.MarkUnsupportedException;
 import org.apache.poi.hpsf.NoPropertySetStreamException;
 import org.apache.poi.hpsf.PropertySet;
 import org.apache.poi.hpsf.PropertySetFactory;
@@ -70,7 +69,7 @@ class TestReadAllFiles {
      */
     @ParameterizedTest
     @MethodSource("files")
-    void read(File file) throws IOException, NoPropertySetStreamException, MarkUnsupportedException {
+    void read(File file) throws IOException, NoPropertySetStreamException {
         /* Read the POI filesystem's property set streams: */
         for (POIFile pf : Util.readPropertySets(file)) {
             try (InputStream in = new ByteArrayInputStream(pf.getBytes())) {
@@ -84,7 +83,7 @@ class TestReadAllFiles {
     /**
      * This test method does a write and read back test with all POI
      * filesystems in the "data" directory by performing the following
-     * actions for each file:<p>
+     * actions for each file:
      *
      * <ul>
      * <li>Read its property set streams.
@@ -102,35 +101,35 @@ class TestReadAllFiles {
 
         /* Create a new POI filesystem containing the origin file's
          * property set streams: */
-        ByteArrayOutputStream bos = new ByteArrayOutputStream();
-        final POIFSFileSystem poiFs = new POIFSFileSystem();
-        for (POIFile poifile : Util.readPropertySets(file)) {
-            final InputStream in = new ByteArrayInputStream(poifile.getBytes());
-            final PropertySet psIn = PropertySetFactory.create(in);
-            psMap.put(poifile.getName(), psIn);
-            bos.reset();
-            psIn.write(bos);
-            poiFs.createDocument(new ByteArrayInputStream(bos.toByteArray()), poifile.getName());
-        }
+        UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream();
+        try (POIFSFileSystem poiFs = new POIFSFileSystem()) {
+            for (POIFile poifile : Util.readPropertySets(file)) {
+                final InputStream in = new ByteArrayInputStream(poifile.getBytes());
+                final PropertySet psIn = PropertySetFactory.create(in);
+                psMap.put(poifile.getName(), psIn);
+                bos.reset();
+                psIn.write(bos);
+                poiFs.createDocument(bos.toInputStream(), poifile.getName());
+            }
 
-        /* Read the property set streams from the POI filesystem just
-         * created. */
-        for (Map.Entry<String,PropertySet> me : psMap.entrySet()) {
-            final PropertySet ps1 = me.getValue();
-            final PropertySet ps2 = PropertySetFactory.create(poiFs.getRoot(), me.getKey());
-            assertNotNull(ps2);
+            /* Read the property set streams from the POI filesystem just
+             * created. */
+            for (Map.Entry<String, PropertySet> me : psMap.entrySet()) {
+                final PropertySet ps1 = me.getValue();
+                final PropertySet ps2 = PropertySetFactory.create(poiFs.getRoot(), me.getKey());
+                assertNotNull(ps2);
 
-            /* Compare the property set stream with the corresponding one
-             * from the origin file and check whether they are equal. */
+                /* Compare the property set stream with the corresponding one
+                 * from the origin file and check whether they are equal. */
 
-            // Because of missing 0-paddings in the original input files, the bytes might differ.
-            // This fixes the comparison
-            String ps1str = ps1.toString().replace(" 00", "   ").replace(".", " ").replaceAll("(?m)( +$|(size|offset): [0-9]+)","");
-            String ps2str = ps2.toString().replace(" 00", "   ").replace(".", " ").replaceAll("(?m)( +$|(size|offset): [0-9]+)","");
+                // Because of missing 0-paddings in the original input files, the bytes might differ.
+                // This fixes the comparison
+                String ps1str = ps1.toString().replace(" 00", "   ").replace(".", " ").replaceAll("(?m)( +$|(size|offset): [0-9]+)", "");
+                String ps2str = ps2.toString().replace(" 00", "   ").replace(".", " ").replaceAll("(?m)( +$|(size|offset): [0-9]+)", "");
 
-            assertEquals(ps1str, ps2str, "Equality for file " + file.getName());
+                assertEquals(ps1str, ps2str, "Equality for file " + file.getName());
+            }
         }
-        poiFs.close();
     }
 
     /**
diff --git a/poi/src/test/java/org/apache/poi/hpsf/basic/TestWrite.java b/poi/src/test/java/org/apache/poi/hpsf/basic/TestWrite.java
index 85ae090206..7d1df36fb8 100644
--- a/poi/src/test/java/org/apache/poi/hpsf/basic/TestWrite.java
+++ b/poi/src/test/java/org/apache/poi/hpsf/basic/TestWrite.java
@@ -26,10 +26,8 @@ import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertNull;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
-import static org.junit.jupiter.api.Assertions.fail;
 
 import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.FileOutputStream;
 import java.io.IOException;
@@ -44,6 +42,7 @@ import java.util.List;
 import java.util.Locale;
 import java.util.Map;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.POIDataSamples;
 import org.apache.poi.hpsf.ClassID;
 import org.apache.poi.hpsf.ClassIDPredefined;
@@ -118,9 +117,9 @@ class TestWrite {
         /* Write it to a POIFS and the latter to disk: */
         try (OutputStream out = new FileOutputStream(filename);
              POIFSFileSystem poiFs = new POIFSFileSystem();
-             ByteArrayOutputStream psStream = new ByteArrayOutputStream()) {
+             UnsynchronizedByteArrayOutputStream psStream = new UnsynchronizedByteArrayOutputStream()) {
             assertThrows(NoFormatIDException.class, () -> ps.write(psStream));
-            poiFs.createDocument(new ByteArrayInputStream(psStream.toByteArray()), SummaryInformation.DEFAULT_STREAM_NAME);
+            poiFs.createDocument(psStream.toInputStream(), SummaryInformation.DEFAULT_STREAM_NAME);
             poiFs.writeFilesystem(out);
         }
     }
@@ -142,12 +141,12 @@ class TestWrite {
         /* Create a mutable property set and write it to a POIFS: */
         try (OutputStream out = new FileOutputStream(filename);
             POIFSFileSystem poiFs = new POIFSFileSystem();
-             ByteArrayOutputStream psStream = new ByteArrayOutputStream()) {
+             UnsynchronizedByteArrayOutputStream psStream = new UnsynchronizedByteArrayOutputStream()) {
             final PropertySet ps = new PropertySet();
             final Section s = ps.getSections().get(0);
             s.setFormatID(SummaryInformation.FORMAT_ID);
             ps.write(psStream);
-            poiFs.createDocument(new ByteArrayInputStream(psStream.toByteArray()), SummaryInformation.DEFAULT_STREAM_NAME);
+            poiFs.createDocument(psStream.toInputStream(), SummaryInformation.DEFAULT_STREAM_NAME);
             poiFs.writeFilesystem(out);
         }
 
@@ -254,9 +253,8 @@ class TestWrite {
         /* Read the POIFS: */
         final PropertySet[] psa = new PropertySet[1];
         final POIFSReader r = new POIFSReader();
-        final POIFSReaderListener listener = (event) -> {
+        final POIFSReaderListener listener = (event) ->
             assertDoesNotThrow(() -> psa[0] = PropertySetFactory.create(event.getStream()));
-        };
 
         r.registerListener(listener,STREAM_NAME);
         r.read(filename);
@@ -357,9 +355,8 @@ class TestWrite {
         p.setValue(TITLE);
         ms.setProperty(p);
 
-        ByteArrayOutputStream out = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream out = new UnsynchronizedByteArrayOutputStream();
         mps.write(out);
-        out.close();
         byte[] bytes = out.toByteArray();
 
         PropertySet psr = new PropertySet(bytes);
@@ -388,9 +385,8 @@ class TestWrite {
     private void check(final long variantType, final Object value, final int codepage)
     throws UnsupportedVariantTypeException, IOException
     {
-        final ByteArrayOutputStream out = new ByteArrayOutputStream();
+        final UnsynchronizedByteArrayOutputStream out = new UnsynchronizedByteArrayOutputStream();
         VariantSupport.write(out, variantType, value, codepage);
-        out.close();
         final byte[] b = out.toByteArray();
         final Object objRead =
             VariantSupport.read(b, 0, b.length + LittleEndianConsts.INT_SIZE, variantType, codepage);
@@ -402,7 +398,7 @@ class TestWrite {
     }
 
     /**
-     * <p>Tests writing and reading back a proper dictionary.</p>
+     * Tests writing and reading back a proper dictionary.
      */
     @Test
     void dictionary() throws IOException, HPSFException {
@@ -410,37 +406,36 @@ class TestWrite {
         copy.deleteOnExit();
 
         /* Write: */
-        final OutputStream out = new FileOutputStream(copy);
-        final POIFSFileSystem poiFs = new POIFSFileSystem();
-        final PropertySet ps1 = new PropertySet();
-        final Section s = ps1.getSections().get(0);
-        final Map<Long,String> m = new HashMap<>(3, 1.0f);
-        m.put(1L, "String 1");
-        m.put(2L, "String 2");
-        m.put(3L, "String 3");
-        s.setDictionary(m);
-        s.setFormatID(DocumentSummaryInformation.FORMAT_ID[0]);
-        int codepage = CodePageUtil.CP_UNICODE;
-        s.setProperty(PropertyIDMap.PID_CODEPAGE, Variant.VT_I2, codepage);
-        poiFs.createDocument(ps1.toInputStream(), "Test");
-        poiFs.writeFilesystem(out);
-        poiFs.close();
-        out.close();
-
-        /* Read back: */
-        final List<POIFile> psf = Util.readPropertySets(copy);
-        assertEquals(1, psf.size());
-        final byte[] bytes = psf.get(0).getBytes();
-        final InputStream in = new ByteArrayInputStream(bytes);
-        final PropertySet ps2 = PropertySetFactory.create(in);
-
-        /* Check if the result is a DocumentSummaryInformation stream, as
-         * specified. */
-        assertTrue(ps2.isDocumentSummaryInformation());
-
-        /* Compare the property set stream with the corresponding one
-         * from the origin file and check whether they are equal. */
-        assertEquals(ps1, ps2);
+        try (OutputStream out = new FileOutputStream(copy);
+            POIFSFileSystem poiFs = new POIFSFileSystem()) {
+            final PropertySet ps1 = new PropertySet();
+            final Section s = ps1.getSections().get(0);
+            final Map<Long, String> m = new HashMap<>(3, 1.0f);
+            m.put(1L, "String 1");
+            m.put(2L, "String 2");
+            m.put(3L, "String 3");
+            s.setDictionary(m);
+            s.setFormatID(DocumentSummaryInformation.FORMAT_ID[0]);
+            int codepage = CodePageUtil.CP_UNICODE;
+            s.setProperty(PropertyIDMap.PID_CODEPAGE, Variant.VT_I2, codepage);
+            poiFs.createDocument(ps1.toInputStream(), "Test");
+            poiFs.writeFilesystem(out);
+
+            /* Read back: */
+            final List<POIFile> psf = Util.readPropertySets(copy);
+            assertEquals(1, psf.size());
+            final byte[] bytes = psf.get(0).getBytes();
+            final InputStream in = new ByteArrayInputStream(bytes);
+            final PropertySet ps2 = PropertySetFactory.create(in);
+
+            /* Check if the result is a DocumentSummaryInformation stream, as
+             * specified. */
+            assertTrue(ps2.isDocumentSummaryInformation());
+
+            /* Compare the property set stream with the corresponding one
+             * from the origin file and check whether they are equal. */
+            assertEquals(ps1, ps2);
+        }
     }
 
     /**
@@ -543,9 +538,9 @@ class TestWrite {
             doufStream.close();
 
             // And also write to some bytes for checking
-            ByteArrayOutputStream sinfBytes = new ByteArrayOutputStream();
+            UnsynchronizedByteArrayOutputStream sinfBytes = new UnsynchronizedByteArrayOutputStream();
             sinf.write(sinfBytes);
-            ByteArrayOutputStream dinfBytes = new ByteArrayOutputStream();
+            UnsynchronizedByteArrayOutputStream dinfBytes = new UnsynchronizedByteArrayOutputStream();
             dinf.write(dinfBytes);
 
 
@@ -656,7 +651,7 @@ class TestWrite {
      * codepage. (HPSF writes Unicode dictionaries only.)
      */
     @Test
-    void dictionaryWithInvalidCodepage() throws IOException, HPSFException {
+    void dictionaryWithInvalidCodepage() throws IOException {
         final File copy = TempFile.createTempFile("Test-HPSF", "ole2");
         copy.deleteOnExit();
 
@@ -696,8 +691,8 @@ class TestWrite {
      * method checks whether the application is runing in an environment
      * where the default character set is 16-bit-capable.</p>
      *
-     * @return <code>true</code> if the default character set is 16-bit-capable,
-     * else <code>false</code>.
+     * @return {@code true} if the default character set is 16-bit-capable,
+     * else {@code false}.
      */
     private boolean hasProperDefaultCharset() {
         final String charSetName = System.getProperty("file.encoding");
diff --git a/poi/src/test/java/org/apache/poi/hssf/HSSFTestDataSamples.java b/poi/src/test/java/org/apache/poi/hssf/HSSFTestDataSamples.java
index 3835802725..fbef50b6af 100644
--- a/poi/src/test/java/org/apache/poi/hssf/HSSFTestDataSamples.java
+++ b/poi/src/test/java/org/apache/poi/hssf/HSSFTestDataSamples.java
@@ -17,12 +17,11 @@
 
 package org.apache.poi.hssf;
 
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.POIDataSamples;
 import org.apache.poi.hssf.usermodel.HSSFWorkbook;
 
@@ -56,11 +55,11 @@ public final class HSSFTestDataSamples {
 	 * Useful for verifying that the serialisation round trip
 	 */
 	public static HSSFWorkbook writeOutAndReadBack(HSSFWorkbook original) {
-		try {
-			ByteArrayOutputStream baos = new ByteArrayOutputStream(4096);
+		try (UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream()) {
 			original.write(baos);
-			ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
-			return new HSSFWorkbook(bais);
+			try (InputStream is = baos.toInputStream()) {
+				return new HSSFWorkbook(is);
+			}
 		} catch (IOException e) {
 			throw new RuntimeException(e);
 		}
diff --git a/poi/src/test/java/org/apache/poi/hssf/dev/TestBiffDrawingToXml.java b/poi/src/test/java/org/apache/poi/hssf/dev/TestBiffDrawingToXml.java
index 0f346f50ee..a957f67557 100644
--- a/poi/src/test/java/org/apache/poi/hssf/dev/TestBiffDrawingToXml.java
+++ b/poi/src/test/java/org/apache/poi/hssf/dev/TestBiffDrawingToXml.java
@@ -16,6 +16,8 @@
 ==================================================================== */
 package org.apache.poi.hssf.dev;
 
+import static org.apache.commons.io.output.NullOutputStream.NULL_OUTPUT_STREAM;
+
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.InputStream;
@@ -23,7 +25,6 @@ import java.util.Map;
 
 import org.apache.poi.EncryptedDocumentException;
 import org.apache.poi.hssf.record.RecordInputStream;
-import org.apache.poi.util.NullOutputStream;
 
 class TestBiffDrawingToXml extends BaseTestIteratingXLS {
 
@@ -44,7 +45,7 @@ class TestBiffDrawingToXml extends BaseTestIteratingXLS {
 	@Override
 	void runOneFile(File pFile) throws Exception {
         try (InputStream wb = new FileInputStream(pFile)) {
-            BiffDrawingToXml.writeToFile(new NullOutputStream(), wb, false, new String[0]);
+            BiffDrawingToXml.writeToFile(NULL_OUTPUT_STREAM, wb, false, new String[0]);
         }
 	}
 }
diff --git a/poi/src/test/java/org/apache/poi/hssf/dev/TestBiffViewer.java b/poi/src/test/java/org/apache/poi/hssf/dev/TestBiffViewer.java
index 0a99128a76..790ca14b58 100644
--- a/poi/src/test/java/org/apache/poi/hssf/dev/TestBiffViewer.java
+++ b/poi/src/test/java/org/apache/poi/hssf/dev/TestBiffViewer.java
@@ -16,6 +16,8 @@
 ==================================================================== */
 package org.apache.poi.hssf.dev;
 
+import static org.apache.commons.io.output.NullOutputStream.NULL_OUTPUT_STREAM;
+
 import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
@@ -25,7 +27,6 @@ import java.util.Map;
 
 import org.apache.poi.poifs.filesystem.POIFSFileSystem;
 import org.apache.poi.util.LocaleUtil;
-import org.apache.poi.util.NullOutputStream;
 import org.apache.poi.util.RecordFormatException;
 
 class TestBiffViewer extends BaseTestIteratingXLS {
@@ -54,7 +55,7 @@ class TestBiffViewer extends BaseTestIteratingXLS {
         try (POIFSFileSystem fs = new POIFSFileSystem(fileIn, true);
              InputStream is = BiffViewer.getPOIFSInputStream(fs)) {
             // use a NullOutputStream to not write the bytes anywhere for best runtime
-            PrintWriter dummy = new PrintWriter(new OutputStreamWriter(new NullOutputStream(), LocaleUtil.CHARSET_1252));
+            PrintWriter dummy = new PrintWriter(new OutputStreamWriter(NULL_OUTPUT_STREAM, LocaleUtil.CHARSET_1252));
             BiffViewer.runBiffViewer(dummy, is, true, true, true, false);
         }
     }
diff --git a/poi/src/test/java/org/apache/poi/hssf/dev/TestEFBiffViewer.java b/poi/src/test/java/org/apache/poi/hssf/dev/TestEFBiffViewer.java
index 9f072b37b3..79f8e7f426 100644
--- a/poi/src/test/java/org/apache/poi/hssf/dev/TestEFBiffViewer.java
+++ b/poi/src/test/java/org/apache/poi/hssf/dev/TestEFBiffViewer.java
@@ -23,7 +23,7 @@ import java.util.Map;
 
 import org.apache.poi.EncryptedDocumentException;
 import org.apache.poi.hssf.record.RecordInputStream;
-import org.apache.poi.util.NullPrintStream;
+import org.apache.commons.io.output.NullPrintStream;
 import org.junit.jupiter.api.parallel.ResourceLock;
 import org.junit.jupiter.api.parallel.Resources;
 
@@ -32,13 +32,16 @@ class TestEFBiffViewer extends BaseTestIteratingXLS {
     @Override
     protected Map<String, Class<? extends Throwable>> getExcludes() {
         Map<String, Class<? extends Throwable>> excludes = super.getExcludes();
-        excludes.put("35897-type4.xls", EncryptedDocumentException.class); // unsupported crypto api header
+		// unsupported crypto api header
+        excludes.put("35897-type4.xls", EncryptedDocumentException.class);
         excludes.put("51832.xls", EncryptedDocumentException.class);
         excludes.put("xor-encryption-abc.xls", EncryptedDocumentException.class);
         excludes.put("password.xls", EncryptedDocumentException.class);
-        excludes.put("43493.xls", RecordInputStream.LeftoverDataException.class);  // HSSFWorkbook cannot open it as well
+		// HSSFWorkbook cannot open it as well
+        excludes.put("43493.xls", RecordInputStream.LeftoverDataException.class);
         excludes.put("44958_1.xls", RecordInputStream.LeftoverDataException.class);
-        // EXCLUDED.put("XRefCalc.xls", RuntimeException.class);            // "Buffer overrun"
+		// "Buffer overrun"
+        excludes.put("XRefCalc.xls", RuntimeException.class);
         return excludes;
     }
 
diff --git a/poi/src/test/java/org/apache/poi/hssf/dev/TestFormulaViewer.java b/poi/src/test/java/org/apache/poi/hssf/dev/TestFormulaViewer.java
index df2247b22c..4f5a7295ac 100644
--- a/poi/src/test/java/org/apache/poi/hssf/dev/TestFormulaViewer.java
+++ b/poi/src/test/java/org/apache/poi/hssf/dev/TestFormulaViewer.java
@@ -24,7 +24,7 @@ import java.util.Map;
 
 import org.apache.poi.EncryptedDocumentException;
 import org.apache.poi.hssf.record.RecordInputStream;
-import org.apache.poi.util.NullPrintStream;
+import org.apache.commons.io.output.NullPrintStream;
 import org.junit.jupiter.api.parallel.ResourceLock;
 import org.junit.jupiter.api.parallel.Resources;
 
diff --git a/poi/src/test/java/org/apache/poi/hssf/dev/TestReSave.java b/poi/src/test/java/org/apache/poi/hssf/dev/TestReSave.java
index 1d890ef4a6..f5e3644acd 100644
--- a/poi/src/test/java/org/apache/poi/hssf/dev/TestReSave.java
+++ b/poi/src/test/java/org/apache/poi/hssf/dev/TestReSave.java
@@ -25,7 +25,7 @@ import java.util.Map;
 import org.apache.poi.EncryptedDocumentException;
 import org.apache.poi.POIDataSamples;
 import org.apache.poi.hssf.record.RecordInputStream;
-import org.apache.poi.util.NullPrintStream;
+import org.apache.commons.io.output.NullPrintStream;
 import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.parallel.Isolated;
diff --git a/poi/src/test/java/org/apache/poi/hssf/dev/TestRecordLister.java b/poi/src/test/java/org/apache/poi/hssf/dev/TestRecordLister.java
index 6087dab647..003f43896a 100644
--- a/poi/src/test/java/org/apache/poi/hssf/dev/TestRecordLister.java
+++ b/poi/src/test/java/org/apache/poi/hssf/dev/TestRecordLister.java
@@ -20,7 +20,7 @@ import java.io.File;
 import java.io.IOException;
 import java.io.PrintStream;
 
-import org.apache.poi.util.NullPrintStream;
+import org.apache.commons.io.output.NullPrintStream;
 import org.junit.jupiter.api.parallel.ResourceLock;
 import org.junit.jupiter.api.parallel.Resources;
 
diff --git a/poi/src/test/java/org/apache/poi/hssf/eventmodel/TestEventRecordFactory.java b/poi/src/test/java/org/apache/poi/hssf/eventmodel/TestEventRecordFactory.java
index 8bb1b6771c..990221b6d2 100644
--- a/poi/src/test/java/org/apache/poi/hssf/eventmodel/TestEventRecordFactory.java
+++ b/poi/src/test/java/org/apache/poi/hssf/eventmodel/TestEventRecordFactory.java
@@ -20,10 +20,10 @@ package org.apache.poi.hssf.eventmodel;
 import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertSame;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.SequenceInputStream;
@@ -31,6 +31,7 @@ import java.util.Iterator;
 import java.util.stream.Stream;
 
 import org.apache.commons.collections4.IteratorUtils;
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.hssf.record.BOFRecord;
 import org.apache.poi.hssf.record.ContinueRecord;
 import org.apache.poi.hssf.record.EOFRecord;
@@ -130,16 +131,15 @@ final class TestEventRecordFactory {
      * OBJECTIVE:  Test that the RecordFactory given an InputStream
      *             constructs the expected records.<P>
      * SUCCESS:    Record factory creates the expected records.<P>
-     * FAILURE:    The wrong records are created or contain the wrong values <P>
-     *
+     * FAILURE:    The wrong records are created or contain the wrong values
      */
     @Test
      void testContinuedUnknownRecord() throws IOException {
-        ByteArrayOutputStream bos = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream();
         for (byte[] b : CONTINUE_DATA) {
             bos.write(b);
         }
-        continueHelper(new ByteArrayInputStream(bos.toByteArray()));
+        continueHelper(bos.toInputStream());
     }
 
     @Test
@@ -156,7 +156,7 @@ final class TestEventRecordFactory {
         Iterator<byte[]> expectedData = Stream.of(CONTINUE_DATA).iterator();
 
         ERFListener listener = rec -> {
-            assertEquals(expectedType.next(), rec.getClass());
+            assertSame(expectedType.next(), rec.getClass());
             assertArrayEquals(expectedData.next(), rec.serialize());
             return true;
         };
diff --git a/poi/src/test/java/org/apache/poi/hssf/extractor/TestOldExcelExtractor.java b/poi/src/test/java/org/apache/poi/hssf/extractor/TestOldExcelExtractor.java
index 7dbabe14b1..c9438fd990 100644
--- a/poi/src/test/java/org/apache/poi/hssf/extractor/TestOldExcelExtractor.java
+++ b/poi/src/test/java/org/apache/poi/hssf/extractor/TestOldExcelExtractor.java
@@ -23,15 +23,16 @@ import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.PrintStream;
+import java.nio.charset.StandardCharsets;
 import java.security.Permission;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.EmptyFileException;
 import org.apache.poi.EncryptedDocumentException;
 import org.apache.poi.POIDataSamples;
@@ -39,7 +40,7 @@ import org.apache.poi.extractor.POITextExtractor;
 import org.apache.poi.hssf.HSSFTestDataSamples;
 import org.apache.poi.poifs.filesystem.OfficeXmlFileException;
 import org.apache.poi.poifs.filesystem.POIFSFileSystem;
-import org.apache.poi.util.NullPrintStream;
+import org.apache.commons.io.output.NullPrintStream;
 import org.apache.poi.util.RecordFormatException;
 import org.junit.jupiter.api.Test;
 
@@ -321,12 +322,11 @@ final class TestOldExcelExtractor {
     void testMain() throws IOException {
         File file = HSSFTestDataSamples.getSampleFile("testEXCEL_3.xls");
         PrintStream save = System.out;
-        try {
-            ByteArrayOutputStream out = new ByteArrayOutputStream();
-            PrintStream str = new PrintStream(out, false, "UTF-8");
+        try (UnsynchronizedByteArrayOutputStream out = new UnsynchronizedByteArrayOutputStream();
+             PrintStream str = new PrintStream(out, false, StandardCharsets.UTF_8.displayName())) {
             System.setOut(str);
             OldExcelExtractor.main(new String[] {file.getAbsolutePath()});
-            String string = out.toString("UTF-8");
+            String string = out.toString(StandardCharsets.UTF_8);
             assertTrue(string.contains("Table C-13--Lemons"), "Had: " + string);
         } finally {
             System.setOut(save);
diff --git a/poi/src/test/java/org/apache/poi/hssf/model/TestDrawingAggregate.java b/poi/src/test/java/org/apache/poi/hssf/model/TestDrawingAggregate.java
index 18138de8ed..59c9eba317 100644
--- a/poi/src/test/java/org/apache/poi/hssf/model/TestDrawingAggregate.java
+++ b/poi/src/test/java/org/apache/poi/hssf/model/TestDrawingAggregate.java
@@ -24,7 +24,6 @@ import static org.junit.jupiter.api.Assertions.assertSame;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.IOException;
 import java.util.ArrayList;
@@ -33,6 +32,7 @@ import java.util.List;
 import java.util.Map;
 import java.util.stream.Stream;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.ddf.DefaultEscherRecordFactory;
 import org.apache.poi.ddf.EscherContainerRecord;
 import org.apache.poi.ddf.EscherDggRecord;
@@ -113,7 +113,7 @@ class TestDrawingAggregate {
          * @return the raw data being aggregated
          */
         byte[] getRawBytes(){
-            ByteArrayOutputStream out = new ByteArrayOutputStream();
+            UnsynchronizedByteArrayOutputStream out = new UnsynchronizedByteArrayOutputStream();
             for (RecordBase rb : aggRecords) {
                 Record r = (org.apache.poi.hssf.record.Record) rb;
                 try {
@@ -216,7 +216,7 @@ class TestDrawingAggregate {
         assertEquals(dgBytes.length, pos, "data was not fully read");
 
         // serialize to byte array
-        ByteArrayOutputStream out = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream out = new UnsynchronizedByteArrayOutputStream();
         for(EscherRecord r : records) {
             out.write(r.serialize());
         }
@@ -242,7 +242,7 @@ class TestDrawingAggregate {
     }
 
     private static byte[] toByteArray(List<RecordBase> records) {
-        ByteArrayOutputStream out = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream out = new UnsynchronizedByteArrayOutputStream();
         for (RecordBase rb : records) {
             Record r = (org.apache.poi.hssf.record.Record) rb;
             try {
diff --git a/poi/src/test/java/org/apache/poi/hssf/model/TestDrawingShapes.java b/poi/src/test/java/org/apache/poi/hssf/model/TestDrawingShapes.java
index 22cd1ee11c..1618e03791 100644
--- a/poi/src/test/java/org/apache/poi/hssf/model/TestDrawingShapes.java
+++ b/poi/src/test/java/org/apache/poi/hssf/model/TestDrawingShapes.java
@@ -469,152 +469,152 @@ class TestDrawingShapes {
 
     @Test
     void testRemoveShapes() throws IOException {
-        HSSFWorkbook wb1 = new HSSFWorkbook();
-        HSSFSheet sheet = wb1.createSheet();
-        HSSFPatriarch patriarch = sheet.createDrawingPatriarch();
+        try (HSSFWorkbook wb1 = new HSSFWorkbook()) {
+            HSSFSheet sheet1 = wb1.createSheet();
+            HSSFPatriarch patriarch1 = sheet1.createDrawingPatriarch();
 
-        HSSFSimpleShape rectangle = patriarch.createSimpleShape(new HSSFClientAnchor());
-        rectangle.setShapeType(HSSFSimpleShape.OBJECT_TYPE_RECTANGLE);
+            HSSFSimpleShape rectangle = patriarch1.createSimpleShape(new HSSFClientAnchor());
+            rectangle.setShapeType(HSSFSimpleShape.OBJECT_TYPE_RECTANGLE);
 
-        int idx = wb1.addPicture(new byte[]{1,2,3}, Workbook.PICTURE_TYPE_JPEG);
-        patriarch.createPicture(new HSSFClientAnchor(), idx);
+            int idx = wb1.addPicture(new byte[]{1, 2, 3}, Workbook.PICTURE_TYPE_JPEG);
+            patriarch1.createPicture(new HSSFClientAnchor(), idx);
 
-        patriarch.createCellComment(new HSSFClientAnchor());
+            patriarch1.createCellComment(new HSSFClientAnchor());
 
-        HSSFPolygon polygon = patriarch.createPolygon(new HSSFClientAnchor());
-        polygon.setPoints(new int[]{1,2}, new int[]{2,3});
+            HSSFPolygon polygon1 = patriarch1.createPolygon(new HSSFClientAnchor());
+            polygon1.setPoints(new int[]{1, 2}, new int[]{2, 3});
 
-        patriarch.createTextbox(new HSSFClientAnchor());
+            patriarch1.createTextbox(new HSSFClientAnchor());
 
-        HSSFShapeGroup group = patriarch.createGroup(new HSSFClientAnchor());
-        group.createTextbox(new HSSFChildAnchor());
-        group.createPicture(new HSSFChildAnchor(), idx);
+            HSSFShapeGroup group1 = patriarch1.createGroup(new HSSFClientAnchor());
+            group1.createTextbox(new HSSFChildAnchor());
+            group1.createPicture(new HSSFChildAnchor(), idx);
 
-        assertEquals(patriarch.getChildren().size(), 6);
-        assertEquals(group.getChildren().size(), 2);
+            assertEquals(patriarch1.getChildren().size(), 6);
+            assertEquals(group1.getChildren().size(), 2);
 
-        assertEquals(HSSFTestHelper.getEscherAggregate(patriarch).getShapeToObjMapping().size(), 12);
-        assertEquals(HSSFTestHelper.getEscherAggregate(patriarch).getTailRecords().size(), 1);
+            assertEquals(HSSFTestHelper.getEscherAggregate(patriarch1).getShapeToObjMapping().size(), 12);
+            assertEquals(HSSFTestHelper.getEscherAggregate(patriarch1).getTailRecords().size(), 1);
 
-        HSSFWorkbook wb2 = HSSFTestDataSamples.writeOutAndReadBack(wb1);
-        wb1.close();
-        sheet = wb2.getSheetAt(0);
-        patriarch = sheet.getDrawingPatriarch();
+            try (HSSFWorkbook wb2 = HSSFTestDataSamples.writeOutAndReadBack(wb1)) {
+                HSSFSheet sheet2 = wb2.getSheetAt(0);
+                HSSFPatriarch patriarch2 = sheet2.getDrawingPatriarch();
 
-        assertEquals(HSSFTestHelper.getEscherAggregate(patriarch).getShapeToObjMapping().size(), 12);
-        assertEquals(HSSFTestHelper.getEscherAggregate(patriarch).getTailRecords().size(), 1);
+                assertEquals(HSSFTestHelper.getEscherAggregate(patriarch2).getShapeToObjMapping().size(), 12);
+                assertEquals(HSSFTestHelper.getEscherAggregate(patriarch2).getTailRecords().size(), 1);
 
-        assertEquals(patriarch.getChildren().size(), 6);
+                assertEquals(patriarch2.getChildren().size(), 6);
 
-        group = (HSSFShapeGroup) patriarch.getChildren().get(5);
-        group.removeShape(group.getChildren().get(0));
+                HSSFShapeGroup group2 = (HSSFShapeGroup) patriarch2.getChildren().get(5);
+                group2.removeShape(group2.getChildren().get(0));
 
-        assertEquals(HSSFTestHelper.getEscherAggregate(patriarch).getShapeToObjMapping().size(), 10);
-        assertEquals(HSSFTestHelper.getEscherAggregate(patriarch).getTailRecords().size(), 1);
+                assertEquals(HSSFTestHelper.getEscherAggregate(patriarch2).getShapeToObjMapping().size(), 10);
+                assertEquals(HSSFTestHelper.getEscherAggregate(patriarch2).getTailRecords().size(), 1);
 
-        HSSFWorkbook wb3 = HSSFTestDataSamples.writeOutAndReadBack(wb2);
-        wb2.close();
-        sheet = wb3.getSheetAt(0);
-        patriarch = sheet.getDrawingPatriarch();
+                try (HSSFWorkbook wb3 = HSSFTestDataSamples.writeOutAndReadBack(wb2)) {
+                    HSSFSheet sheet3 = wb3.getSheetAt(0);
+                    HSSFPatriarch patriarch3 = sheet3.getDrawingPatriarch();
 
-        assertEquals(HSSFTestHelper.getEscherAggregate(patriarch).getShapeToObjMapping().size(), 10);
-        assertEquals(HSSFTestHelper.getEscherAggregate(patriarch).getTailRecords().size(), 1);
+                    assertEquals(HSSFTestHelper.getEscherAggregate(patriarch3).getShapeToObjMapping().size(), 10);
+                    assertEquals(HSSFTestHelper.getEscherAggregate(patriarch3).getTailRecords().size(), 1);
 
-        group = (HSSFShapeGroup) patriarch.getChildren().get(5);
-        patriarch.removeShape(group);
+                    HSSFShapeGroup group3 = (HSSFShapeGroup) patriarch3.getChildren().get(5);
+                    patriarch3.removeShape(group3);
 
-        assertEquals(HSSFTestHelper.getEscherAggregate(patriarch).getShapeToObjMapping().size(), 8);
-        assertEquals(HSSFTestHelper.getEscherAggregate(patriarch).getTailRecords().size(), 1);
+                    assertEquals(HSSFTestHelper.getEscherAggregate(patriarch3).getShapeToObjMapping().size(), 8);
+                    assertEquals(HSSFTestHelper.getEscherAggregate(patriarch3).getTailRecords().size(), 1);
 
-        HSSFWorkbook wb4 = HSSFTestDataSamples.writeOutAndReadBack(wb3);
-        wb3.close();
-        sheet = wb4.getSheetAt(0);
-        patriarch = sheet.getDrawingPatriarch();
+                    try (HSSFWorkbook wb4 = HSSFTestDataSamples.writeOutAndReadBack(wb3)) {
+                        HSSFSheet sheet4 = wb4.getSheetAt(0);
+                        HSSFPatriarch patriarch4 = sheet4.getDrawingPatriarch();
 
-        assertEquals(HSSFTestHelper.getEscherAggregate(patriarch).getShapeToObjMapping().size(), 8);
-        assertEquals(HSSFTestHelper.getEscherAggregate(patriarch).getTailRecords().size(), 1);
-        assertEquals(patriarch.getChildren().size(), 5);
+                        assertEquals(HSSFTestHelper.getEscherAggregate(patriarch4).getShapeToObjMapping().size(), 8);
+                        assertEquals(HSSFTestHelper.getEscherAggregate(patriarch4).getTailRecords().size(), 1);
+                        assertEquals(patriarch4.getChildren().size(), 5);
 
-        HSSFShape shape = patriarch.getChildren().get(0);
-        patriarch.removeShape(shape);
+                        HSSFShape shape4 = patriarch4.getChildren().get(0);
+                        patriarch4.removeShape(shape4);
 
-        assertEquals(HSSFTestHelper.getEscherAggregate(patriarch).getShapeToObjMapping().size(), 6);
-        assertEquals(HSSFTestHelper.getEscherAggregate(patriarch).getTailRecords().size(), 1);
-        assertEquals(patriarch.getChildren().size(), 4);
+                        assertEquals(HSSFTestHelper.getEscherAggregate(patriarch4).getShapeToObjMapping().size(), 6);
+                        assertEquals(HSSFTestHelper.getEscherAggregate(patriarch4).getTailRecords().size(), 1);
+                        assertEquals(patriarch4.getChildren().size(), 4);
 
-        HSSFWorkbook wb5 = HSSFTestDataSamples.writeOutAndReadBack(wb4);
-        wb4.close();
-        sheet = wb5.getSheetAt(0);
-        patriarch = sheet.getDrawingPatriarch();
+                        try (HSSFWorkbook wb5 = HSSFTestDataSamples.writeOutAndReadBack(wb4)) {
+                            HSSFSheet sheet5 = wb5.getSheetAt(0);
+                            HSSFPatriarch patriarch5 = sheet5.getDrawingPatriarch();
 
-        assertEquals(HSSFTestHelper.getEscherAggregate(patriarch).getShapeToObjMapping().size(), 6);
-        assertEquals(HSSFTestHelper.getEscherAggregate(patriarch).getTailRecords().size(), 1);
-        assertEquals(patriarch.getChildren().size(), 4);
+                            assertEquals(HSSFTestHelper.getEscherAggregate(patriarch5).getShapeToObjMapping().size(), 6);
+                            assertEquals(HSSFTestHelper.getEscherAggregate(patriarch5).getTailRecords().size(), 1);
+                            assertEquals(patriarch5.getChildren().size(), 4);
 
-        HSSFPicture picture = (HSSFPicture) patriarch.getChildren().get(0);
-        patriarch.removeShape(picture);
+                            HSSFPicture picture5 = (HSSFPicture) patriarch5.getChildren().get(0);
+                            patriarch5.removeShape(picture5);
 
-        assertEquals(HSSFTestHelper.getEscherAggregate(patriarch).getShapeToObjMapping().size(), 5);
-        assertEquals(HSSFTestHelper.getEscherAggregate(patriarch).getTailRecords().size(), 1);
-        assertEquals(patriarch.getChildren().size(), 3);
+                            assertEquals(HSSFTestHelper.getEscherAggregate(patriarch5).getShapeToObjMapping().size(), 5);
+                            assertEquals(HSSFTestHelper.getEscherAggregate(patriarch5).getTailRecords().size(), 1);
+                            assertEquals(patriarch5.getChildren().size(), 3);
 
-        HSSFWorkbook wb6 = HSSFTestDataSamples.writeOutAndReadBack(wb5);
-        wb5.close();
-        sheet = wb6.getSheetAt(0);
-        patriarch = sheet.getDrawingPatriarch();
+                            try (HSSFWorkbook wb6 = HSSFTestDataSamples.writeOutAndReadBack(wb5)) {
+                                HSSFSheet sheet6 = wb6.getSheetAt(0);
+                                HSSFPatriarch patriarch6 = sheet6.getDrawingPatriarch();
 
-        assertEquals(HSSFTestHelper.getEscherAggregate(patriarch).getShapeToObjMapping().size(), 5);
-        assertEquals(HSSFTestHelper.getEscherAggregate(patriarch).getTailRecords().size(), 1);
-        assertEquals(patriarch.getChildren().size(), 3);
+                                assertEquals(HSSFTestHelper.getEscherAggregate(patriarch6).getShapeToObjMapping().size(), 5);
+                                assertEquals(HSSFTestHelper.getEscherAggregate(patriarch6).getTailRecords().size(), 1);
+                                assertEquals(patriarch6.getChildren().size(), 3);
 
-        HSSFComment comment = (HSSFComment) patriarch.getChildren().get(0);
-        patriarch.removeShape(comment);
+                                HSSFComment comment6 = (HSSFComment) patriarch6.getChildren().get(0);
+                                patriarch6.removeShape(comment6);
 
-        assertEquals(HSSFTestHelper.getEscherAggregate(patriarch).getShapeToObjMapping().size(), 3);
-        assertEquals(HSSFTestHelper.getEscherAggregate(patriarch).getTailRecords().size(), 0);
-        assertEquals(patriarch.getChildren().size(), 2);
+                                assertEquals(HSSFTestHelper.getEscherAggregate(patriarch6).getShapeToObjMapping().size(), 3);
+                                assertEquals(HSSFTestHelper.getEscherAggregate(patriarch6).getTailRecords().size(), 0);
+                                assertEquals(patriarch6.getChildren().size(), 2);
 
-        HSSFWorkbook wb7 = HSSFTestDataSamples.writeOutAndReadBack(wb6);
-        wb6.close();
-        sheet = wb7.getSheetAt(0);
-        patriarch = sheet.getDrawingPatriarch();
+                                try (HSSFWorkbook wb7 = HSSFTestDataSamples.writeOutAndReadBack(wb6)) {
+                                    HSSFSheet sheet7 = wb7.getSheetAt(0);
+                                    HSSFPatriarch patriarch7 = sheet7.getDrawingPatriarch();
 
-        assertEquals(HSSFTestHelper.getEscherAggregate(patriarch).getShapeToObjMapping().size(), 3);
-        assertEquals(HSSFTestHelper.getEscherAggregate(patriarch).getTailRecords().size(), 0);
-        assertEquals(patriarch.getChildren().size(), 2);
+                                    assertEquals(HSSFTestHelper.getEscherAggregate(patriarch7).getShapeToObjMapping().size(), 3);
+                                    assertEquals(HSSFTestHelper.getEscherAggregate(patriarch7).getTailRecords().size(), 0);
+                                    assertEquals(patriarch7.getChildren().size(), 2);
 
-        polygon = (HSSFPolygon) patriarch.getChildren().get(0);
-        patriarch.removeShape(polygon);
+                                    HSSFPolygon polygon7 = (HSSFPolygon) patriarch7.getChildren().get(0);
+                                    patriarch7.removeShape(polygon7);
 
-        assertEquals(HSSFTestHelper.getEscherAggregate(patriarch).getShapeToObjMapping().size(), 2);
-        assertEquals(HSSFTestHelper.getEscherAggregate(patriarch).getTailRecords().size(), 0);
-        assertEquals(patriarch.getChildren().size(), 1);
+                                    assertEquals(HSSFTestHelper.getEscherAggregate(patriarch7).getShapeToObjMapping().size(), 2);
+                                    assertEquals(HSSFTestHelper.getEscherAggregate(patriarch7).getTailRecords().size(), 0);
+                                    assertEquals(patriarch7.getChildren().size(), 1);
 
-        HSSFWorkbook wb8 = HSSFTestDataSamples.writeOutAndReadBack(wb7);
-        wb7.close();
-        sheet = wb8.getSheetAt(0);
-        patriarch = sheet.getDrawingPatriarch();
+                                    try (HSSFWorkbook wb8 = HSSFTestDataSamples.writeOutAndReadBack(wb7)) {
+                                        HSSFSheet sheet8 = wb8.getSheetAt(0);
+                                        HSSFPatriarch patriarch8 = sheet8.getDrawingPatriarch();
 
-        assertEquals(HSSFTestHelper.getEscherAggregate(patriarch).getShapeToObjMapping().size(), 2);
-        assertEquals(HSSFTestHelper.getEscherAggregate(patriarch).getTailRecords().size(), 0);
-        assertEquals(patriarch.getChildren().size(), 1);
+                                        assertEquals(HSSFTestHelper.getEscherAggregate(patriarch8).getShapeToObjMapping().size(), 2);
+                                        assertEquals(HSSFTestHelper.getEscherAggregate(patriarch8).getTailRecords().size(), 0);
+                                        assertEquals(patriarch8.getChildren().size(), 1);
 
-        HSSFTextbox textbox = (HSSFTextbox) patriarch.getChildren().get(0);
-        patriarch.removeShape(textbox);
+                                        HSSFTextbox textbox8 = (HSSFTextbox) patriarch8.getChildren().get(0);
+                                        patriarch8.removeShape(textbox8);
 
-        assertEquals(HSSFTestHelper.getEscherAggregate(patriarch).getShapeToObjMapping().size(), 0);
-        assertEquals(HSSFTestHelper.getEscherAggregate(patriarch).getTailRecords().size(), 0);
-        assertEquals(patriarch.getChildren().size(), 0);
+                                        assertEquals(HSSFTestHelper.getEscherAggregate(patriarch8).getShapeToObjMapping().size(), 0);
+                                        assertEquals(HSSFTestHelper.getEscherAggregate(patriarch8).getTailRecords().size(), 0);
+                                        assertEquals(patriarch8.getChildren().size(), 0);
 
-        HSSFWorkbook wb9 = HSSFTestDataSamples.writeOutAndReadBack(wb8);
-        wb8.close();
-        sheet = wb9.getSheetAt(0);
-        patriarch = sheet.getDrawingPatriarch();
+                                        try (HSSFWorkbook wb9 = HSSFTestDataSamples.writeOutAndReadBack(wb8)) {
+                                            HSSFSheet sheet9 = wb9.getSheetAt(0);
+                                            HSSFPatriarch patriarch9 = sheet9.getDrawingPatriarch();
 
-        assertEquals(HSSFTestHelper.getEscherAggregate(patriarch).getShapeToObjMapping().size(), 0);
-        assertEquals(HSSFTestHelper.getEscherAggregate(patriarch).getTailRecords().size(), 0);
-        assertEquals(patriarch.getChildren().size(), 0);
-        wb9.close();
+                                            assertEquals(HSSFTestHelper.getEscherAggregate(patriarch9).getShapeToObjMapping().size(), 0);
+                                            assertEquals(HSSFTestHelper.getEscherAggregate(patriarch9).getTailRecords().size(), 0);
+                                            assertEquals(patriarch9.getChildren().size(), 0);
+                                        }
+                                    }
+                                }
+                            }
+                        }
+                    }
+                }
+            }
+        }
     }
 
     @Test
diff --git a/poi/src/test/java/org/apache/poi/hssf/model/TestEscherRecordFactory.java b/poi/src/test/java/org/apache/poi/hssf/model/TestEscherRecordFactory.java
index efd3f5feff..69566e59f5 100644
--- a/poi/src/test/java/org/apache/poi/hssf/model/TestEscherRecordFactory.java
+++ b/poi/src/test/java/org/apache/poi/hssf/model/TestEscherRecordFactory.java
@@ -17,20 +17,16 @@
 
 package org.apache.poi.hssf.model;
 
-import static org.apache.poi.ddf.DefaultEscherRecordFactory.isContainer;
 import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.util.List;
-import java.util.Random;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.ddf.EscherContainerRecord;
-import org.apache.poi.ddf.EscherTextboxRecord;
 import org.apache.poi.hssf.HSSFTestDataSamples;
 import org.apache.poi.hssf.record.EscherAggregate;
 import org.apache.poi.hssf.record.Record;
@@ -43,7 +39,7 @@ import org.junit.jupiter.api.Test;
 class TestEscherRecordFactory {
 
     private static byte[] toByteArray(List<RecordBase> records) {
-        ByteArrayOutputStream out = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream out = new UnsynchronizedByteArrayOutputStream();
         for (RecordBase rb : records) {
             Record r = (org.apache.poi.hssf.record.Record) rb;
             try {
@@ -56,31 +52,6 @@ class TestEscherRecordFactory {
     }
 
     @Test
-    void testDetectContainer() {
-        Random rnd = new Random();
-        assertTrue(isContainer((short) 0x0, EscherContainerRecord.DG_CONTAINER));
-        assertTrue(isContainer((short) 0x0, EscherContainerRecord.SOLVER_CONTAINER));
-        assertTrue(isContainer((short) 0x0, EscherContainerRecord.SP_CONTAINER));
-        assertTrue(isContainer((short) 0x0, EscherContainerRecord.DGG_CONTAINER));
-        assertTrue(isContainer((short) 0x0, EscherContainerRecord.BSTORE_CONTAINER));
-        assertTrue(isContainer((short) 0x0, EscherContainerRecord.SPGR_CONTAINER));
-
-        for (short i=EscherContainerRecord.DGG_CONTAINER; i<= EscherContainerRecord.SOLVER_CONTAINER; i++){
-            assertTrue(isContainer(Integer.valueOf(rnd.nextInt(Short.MAX_VALUE)).shortValue(), i));
-        }
-
-        assertFalse(isContainer((short) 0x0, Integer.valueOf(EscherContainerRecord.DGG_CONTAINER - 1).shortValue()));
-        assertFalse(isContainer((short) 0x0, Integer.valueOf(EscherContainerRecord.SOLVER_CONTAINER + 1).shortValue()));
-
-        assertTrue(isContainer((short) 0x000F, Integer.valueOf(EscherContainerRecord.DGG_CONTAINER - 1).shortValue()));
-        assertTrue(isContainer((short) 0xFFFF, Integer.valueOf(EscherContainerRecord.DGG_CONTAINER - 1).shortValue()));
-        assertFalse(isContainer((short) 0x000C, Integer.valueOf(EscherContainerRecord.DGG_CONTAINER - 1).shortValue()));
-        assertFalse(isContainer((short) 0xCCCC, Integer.valueOf(EscherContainerRecord.DGG_CONTAINER - 1).shortValue()));
-        assertFalse(isContainer((short) 0x000F, EscherTextboxRecord.RECORD_ID));
-        assertFalse(isContainer((short) 0xCCCC, EscherTextboxRecord.RECORD_ID));
-    }
-
-    @Test
     void testDgContainerMustBeRootOfHSSFSheetEscherRecords() {
         HSSFWorkbook wb = HSSFTestDataSamples.openSampleWorkbook("47251.xls");
         HSSFSheet sh = wb.getSheetAt(0);
diff --git a/poi/src/test/java/org/apache/poi/hssf/record/TestDConRefRecord.java b/poi/src/test/java/org/apache/poi/hssf/record/TestDConRefRecord.java
index c6ea64d6b6..466f596650 100644
--- a/poi/src/test/java/org/apache/poi/hssf/record/TestDConRefRecord.java
+++ b/poi/src/test/java/org/apache/poi/hssf/record/TestDConRefRecord.java
@@ -24,10 +24,10 @@ import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.util.Arrays;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.util.LittleEndianOutputStream;
 import org.junit.jupiter.api.Test;
 
@@ -209,7 +209,7 @@ class TestDConRefRecord {
     private void testReadWrite(byte[] data, String message) throws IOException {
         RecordInputStream is = TestcaseRecordInputStream.create(81, data);
         DConRefRecord d = new DConRefRecord(is);
-        ByteArrayOutputStream bos = new ByteArrayOutputStream(data.length);
+        UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream(data.length);
         LittleEndianOutputStream o = new LittleEndianOutputStream(bos);
         d.serialize(o);
         o.flush();
diff --git a/poi/src/test/java/org/apache/poi/hssf/record/TestDrawingRecord.java b/poi/src/test/java/org/apache/poi/hssf/record/TestDrawingRecord.java
index bac766e08a..d519393c8c 100644
--- a/poi/src/test/java/org/apache/poi/hssf/record/TestDrawingRecord.java
+++ b/poi/src/test/java/org/apache/poi/hssf/record/TestDrawingRecord.java
@@ -21,12 +21,11 @@ import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.util.Arrays;
 import java.util.List;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.junit.jupiter.api.Test;
 
 final class TestDrawingRecord {
@@ -39,7 +38,7 @@ final class TestDrawingRecord {
     void testReadContinued() throws IOException {
 
         //simulate a continues drawing record
-        ByteArrayOutputStream out = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream out = new UnsynchronizedByteArrayOutputStream();
         //main part
         DrawingRecord dg = new DrawingRecord();
         byte[] data1 = new byte[8224];
@@ -53,7 +52,7 @@ final class TestDrawingRecord {
         ContinueRecord cn = new ContinueRecord(data2);
         out.write(cn.serialize());
 
-        List<org.apache.poi.hssf.record.Record> rec = RecordFactory.createRecords(new ByteArrayInputStream(out.toByteArray()));
+        List<org.apache.poi.hssf.record.Record> rec = RecordFactory.createRecords(out.toInputStream());
         assertEquals(2, rec.size());
         assertTrue(rec.get(0) instanceof DrawingRecord);
         assertTrue(rec.get(1) instanceof ContinueRecord);
diff --git a/poi/src/test/java/org/apache/poi/hssf/record/TestLbsDataSubRecord.java b/poi/src/test/java/org/apache/poi/hssf/record/TestLbsDataSubRecord.java
index afd988fb37..005d03d6ef 100644
--- a/poi/src/test/java/org/apache/poi/hssf/record/TestLbsDataSubRecord.java
+++ b/poi/src/test/java/org/apache/poi/hssf/record/TestLbsDataSubRecord.java
@@ -25,9 +25,9 @@ import static org.junit.jupiter.api.Assertions.assertNull;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.ss.formula.ptg.AreaPtg;
 import org.apache.poi.ss.util.CellRangeAddress;
 import org.apache.poi.util.HexRead;
@@ -166,7 +166,7 @@ final class TestLbsDataSubRecord {
         try (LittleEndianInputStream in = new LittleEndianInputStream(new ByteArrayInputStream(data))) {
             LbsDataSubRecord.LbsDropData lbs = new LbsDataSubRecord.LbsDropData(in);
 
-            ByteArrayOutputStream baos = new ByteArrayOutputStream();
+            UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
             try (LittleEndianOutputStream out = new LittleEndianOutputStream(baos)) {
                 lbs.serialize(out);
 
diff --git a/poi/src/test/java/org/apache/poi/hssf/record/TestRecordFactory.java b/poi/src/test/java/org/apache/poi/hssf/record/TestRecordFactory.java
index 11f66367e1..01dee7e08e 100644
--- a/poi/src/test/java/org/apache/poi/hssf/record/TestRecordFactory.java
+++ b/poi/src/test/java/org/apache/poi/hssf/record/TestRecordFactory.java
@@ -22,11 +22,11 @@ import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.util.List;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.poifs.filesystem.POIFSFileSystem;
 import org.apache.poi.util.HexRead;
 import org.junit.jupiter.api.Test;
@@ -185,7 +185,7 @@ final class TestRecordFactory {
 		assertTrue(records.get(4) instanceof ObjRecord);
 
 		//serialize and verify that the serialized data is the same as the original
-		ByteArrayOutputStream out = new ByteArrayOutputStream();
+		UnsynchronizedByteArrayOutputStream out = new UnsynchronizedByteArrayOutputStream();
 		for(org.apache.poi.hssf.record.Record rec : records){
 			out.write(rec.serialize());
 		}
@@ -204,7 +204,7 @@ final class TestRecordFactory {
 			BOFRecord.createSheetBOF(),
 			EOFRecord.instance,
 		};
-		ByteArrayOutputStream baos = new ByteArrayOutputStream();
+		UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
 		for (org.apache.poi.hssf.record.Record rec : recs) {
 			try {
 				baos.write(rec.serialize());
@@ -222,13 +222,13 @@ final class TestRecordFactory {
 		}
 
 
-		POIFSFileSystem fs = new POIFSFileSystem();
-        fs.createDocument(new ByteArrayInputStream(baos.toByteArray()), "dummy");
-		InputStream is = fs.getRoot().createDocumentInputStream("dummy");
+		try (POIFSFileSystem fs = new POIFSFileSystem()) {
+			fs.createDocument(baos.toInputStream(), "dummy");
+			InputStream is = fs.getRoot().createDocumentInputStream("dummy");
 
-		List<org.apache.poi.hssf.record.Record> outRecs = RecordFactory.createRecords(is);
-		// Buffer underrun - requested 512 bytes but 192 was available
-		assertEquals(5, outRecs.size());
-		fs.close();
+			List<org.apache.poi.hssf.record.Record> outRecs = RecordFactory.createRecords(is);
+			// Buffer underrun - requested 512 bytes but 192 was available
+			assertEquals(5, outRecs.size());
+		}
 	}
 }
diff --git a/poi/src/test/java/org/apache/poi/hssf/record/TestSSTRecord.java b/poi/src/test/java/org/apache/poi/hssf/record/TestSSTRecord.java
index b2206b86b7..eed605b661 100644
--- a/poi/src/test/java/org/apache/poi/hssf/record/TestSSTRecord.java
+++ b/poi/src/test/java/org/apache/poi/hssf/record/TestSSTRecord.java
@@ -24,13 +24,13 @@ import static org.junit.jupiter.api.Assertions.fail;
 
 import java.io.BufferedReader;
 import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.InputStreamReader;
 import java.util.Arrays;
 import java.util.Iterator;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.hssf.HSSFTestDataSamples;
 import org.apache.poi.hssf.record.common.UnicodeString;
 import org.apache.poi.hssf.usermodel.HSSFSheet;
@@ -49,7 +49,7 @@ final class TestSSTRecord {
      */
     private static byte[] concatHexDumps(String... hexDumpFileNames) throws IOException {
         int nFiles = hexDumpFileNames.length;
-        ByteArrayOutputStream baos = new ByteArrayOutputStream(nFiles * 8228);
+        UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream(nFiles * 8228);
         for (String sampleFileName : hexDumpFileNames) {
             try (InputStream is = HSSFTestDataSamples.openSampleFileStream(sampleFileName)) {
                 BufferedReader br = new BufferedReader(new InputStreamReader(is, LocaleUtil.CHARSET_1252));
diff --git a/poi/src/test/java/org/apache/poi/hssf/record/common/TestUnicodeString.java b/poi/src/test/java/org/apache/poi/hssf/record/common/TestUnicodeString.java
index 35f84590f7..57b344bd25 100644
--- a/poi/src/test/java/org/apache/poi/hssf/record/common/TestUnicodeString.java
+++ b/poi/src/test/java/org/apache/poi/hssf/record/common/TestUnicodeString.java
@@ -21,10 +21,10 @@ import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.util.Arrays;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.hssf.record.ContinueRecord;
 import org.apache.poi.hssf.record.RecordInputStream;
 import org.apache.poi.hssf.record.SSTRecord;
@@ -36,11 +36,11 @@ import org.apache.poi.ss.usermodel.CellStyle;
 import org.apache.poi.ss.usermodel.Row;
 import org.apache.poi.ss.usermodel.Sheet;
 import org.apache.poi.util.LittleEndianByteArrayInputStream;
-import org.apache.poi.util.LittleEndianByteArrayOutputStream;
 import org.apache.poi.util.LittleEndianConsts;
 import org.apache.poi.util.LittleEndianInput;
 import org.apache.poi.util.LittleEndianInputStream;
 import org.apache.poi.util.LittleEndianOutputStream;
+import org.apache.poi.util.LittleEndianByteArrayOutputStream;
 import org.apache.poi.util.StringUtil;
 import org.junit.jupiter.api.Test;
 
@@ -185,7 +185,7 @@ final class TestUnicodeString {
        assertEquals(4, fr.getCharacterPos());
        assertEquals(0x15c, fr.getFontIndex());
 
-       ByteArrayOutputStream baos = new ByteArrayOutputStream();
+       UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
        LittleEndianOutputStream out = new LittleEndianOutputStream(baos);
 
        fr.serialize(out);
@@ -216,7 +216,7 @@ final class TestUnicodeString {
        assertEquals(0, ext.getPhRuns().length);
        assertEquals(10, ext.getDataSize()); // Excludes 4 byte header
 
-       ByteArrayOutputStream baos = new ByteArrayOutputStream();
+       UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
        LittleEndianOutputStream out = new LittleEndianOutputStream(baos);
        ContinuableRecordOutput cout = new ContinuableRecordOutput(out, 0xffff);
 
diff --git a/poi/src/test/java/org/apache/poi/hssf/usermodel/TestBugs.java b/poi/src/test/java/org/apache/poi/hssf/usermodel/TestBugs.java
index b30f9f71ec..10cad91c66 100644
--- a/poi/src/test/java/org/apache/poi/hssf/usermodel/TestBugs.java
+++ b/poi/src/test/java/org/apache/poi/hssf/usermodel/TestBugs.java
@@ -24,7 +24,6 @@ import static org.junit.jupiter.api.Assertions.*;
 
 import java.awt.image.BufferedImage;
 import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.IOException;
 import java.net.URL;
@@ -46,6 +45,7 @@ import java.util.stream.IntStream;
 
 import javax.imageio.ImageIO;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.hpsf.PropertySet;
 import org.apache.poi.hpsf.SummaryInformation;
 import org.apache.poi.hssf.HSSFITestDataProvider;
@@ -1175,9 +1175,9 @@ final class TestBugs extends BaseTestBugzillaIssues {
     @Test
     void bug32191() throws IOException {
         try (HSSFWorkbook wb = openSampleWorkbook("27394.xls");
-             ByteArrayOutputStream out1 = new ByteArrayOutputStream();
-             ByteArrayOutputStream out2 = new ByteArrayOutputStream();
-             ByteArrayOutputStream out3 = new ByteArrayOutputStream()) {
+             UnsynchronizedByteArrayOutputStream out1 = new UnsynchronizedByteArrayOutputStream();
+             UnsynchronizedByteArrayOutputStream out2 = new UnsynchronizedByteArrayOutputStream();
+             UnsynchronizedByteArrayOutputStream out3 = new UnsynchronizedByteArrayOutputStream()) {
             wb.write(out1);
             wb.write(out2);
             wb.write(out3);
@@ -2220,7 +2220,7 @@ final class TestBugs extends BaseTestBugzillaIssues {
 
     /**
      * Read, write, read for formulas point to cells in other files.
-     * See {@link #bug46670()} for the main test, this just
+     * See bug46670() for the main test, this just
      * covers reading an existing file and checking it.
      *
      * See base-test-class for some related tests that still fail
@@ -2331,7 +2331,7 @@ final class TestBugs extends BaseTestBugzillaIssues {
             }
 
             // Convert BufferedImage to byte[]
-            ByteArrayOutputStream imageBAOS = new ByteArrayOutputStream();
+            UnsynchronizedByteArrayOutputStream imageBAOS = new UnsynchronizedByteArrayOutputStream();
             ImageIO.write(bimage, "jpeg", imageBAOS);
             imageBAOS.flush();
             byte[] imageBytes = imageBAOS.toByteArray();
@@ -2552,7 +2552,7 @@ final class TestBugs extends BaseTestBugzillaIssues {
         "46904.xls, org.apache.poi.hssf.OldExcelFormatException, The supplied spreadsheet seems to be Excel",
         "51832.xls, org.apache.poi.EncryptedDocumentException, Default password is invalid for salt/verifier/verifierHash"
     })
-    void simpleTest(String fileName, String exClazz, String exMessage) throws IOException, ClassNotFoundException {
+    void simpleTest(String fileName, String exClazz, String exMessage) throws ClassNotFoundException {
         Class<? extends Exception> ex = (Class<? extends Exception>)Class.forName(exClazz);
         Exception e = assertThrows(ex, () -> simpleTest(fileName, null));
         assertTrue(e.getMessage().startsWith(exMessage));
diff --git a/poi/src/test/java/org/apache/poi/hssf/usermodel/TestDataValidation.java b/poi/src/test/java/org/apache/poi/hssf/usermodel/TestDataValidation.java
index 777e436e32..36c61a08d8 100644
--- a/poi/src/test/java/org/apache/poi/hssf/usermodel/TestDataValidation.java
+++ b/poi/src/test/java/org/apache/poi/hssf/usermodel/TestDataValidation.java
@@ -24,13 +24,13 @@ import static org.junit.jupiter.api.Assertions.assertNull;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 import static org.junit.jupiter.api.Assertions.fail;
 
-import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.PrintStream;
 import java.util.List;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.hssf.HSSFITestDataProvider;
 import org.apache.poi.hssf.HSSFTestDataSamples;
 import org.apache.poi.hssf.record.DVRecord;
@@ -61,7 +61,7 @@ final class TestDataValidation extends BaseTestDataValidation {
 	void assertDataValidation(Workbook wb) {
 
         byte[] generatedContent;
-		try (ByteArrayOutputStream baos = new ByteArrayOutputStream(22000)) {
+		try (UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream(22000)) {
 			wb.write(baos);
             generatedContent = baos.toByteArray();
 		} catch (IOException e) {
@@ -133,7 +133,7 @@ final class TestDataValidation extends BaseTestDataValidation {
 
             sheet.addValidationData(dv);
 
-            ByteArrayOutputStream baos = new ByteArrayOutputStream();
+            UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
             wb.write(baos);
 
             byte[] wbData = baos.toByteArray();
diff --git a/poi/src/test/java/org/apache/poi/hssf/usermodel/TestEscherGraphics.java b/poi/src/test/java/org/apache/poi/hssf/usermodel/TestEscherGraphics.java
index 3ddac1b794..3b12a4dd32 100644
--- a/poi/src/test/java/org/apache/poi/hssf/usermodel/TestEscherGraphics.java
+++ b/poi/src/test/java/org/apache/poi/hssf/usermodel/TestEscherGraphics.java
@@ -17,6 +17,7 @@
 
 package org.apache.poi.hssf.usermodel;
 
+import static org.apache.poi.hssf.HSSFTestDataSamples.writeOutAndReadBack;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertTrue;
@@ -24,8 +25,6 @@ import static org.junit.jupiter.api.Assertions.assertTrue;
 import java.awt.Color;
 import java.awt.Font;
 import java.awt.FontMetrics;
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 
 import org.junit.jupiter.api.AfterEach;
@@ -46,7 +45,7 @@ final class TestEscherGraphics {
     private EscherGraphics graphics;
 
     @BeforeEach
-    void setUp() throws IOException {
+    void setUp() {
         workbook = new HSSFWorkbook();
 
         HSSFSheet sheet = workbook.createSheet("test");
@@ -82,7 +81,7 @@ final class TestEscherGraphics {
 
     @Test
     void testSetFont() {
-        Font f = new Font("Helvetica", 0, 12);
+        Font f = new Font("Helvetica", Font.PLAIN, 12);
         graphics.setFont(f);
         assertEquals(f, graphics.getFont());
     }
@@ -112,18 +111,15 @@ final class TestEscherGraphics {
     }
 
     @Test
-    void testGetDataBackAgain() throws Exception {
+    void testGetDataBackAgain() {
     	HSSFSheet s;
     	HSSFShapeGroup s1;
     	HSSFShapeGroup s2;
 
     	patriarch.setCoordinates(10, 20, 30, 40);
 
-    	ByteArrayOutputStream baos = new ByteArrayOutputStream();
-    	workbook.write(baos);
-    	workbook = new HSSFWorkbook(new ByteArrayInputStream(baos.toByteArray()));
-    	s = workbook.getSheetAt(0);
-
+		workbook = writeOutAndReadBack(workbook);
+		s = workbook.getSheetAt(0);
     	patriarch = s.getDrawingPatriarch();
 
     	assertNotNull(patriarch);
@@ -160,11 +156,9 @@ final class TestEscherGraphics {
 
 
     	// Write and re-load once more, to check that's ok
-    	baos = new ByteArrayOutputStream();
-    	workbook.write(baos);
-    	workbook = new HSSFWorkbook(new ByteArrayInputStream(baos.toByteArray()));
-    	s = workbook.getSheetAt(0);
-    	patriarch = s.getDrawingPatriarch();
+		workbook = writeOutAndReadBack(workbook);
+		s = workbook.getSheetAt(0);
+		patriarch = s.getDrawingPatriarch();
 
     	assertNotNull(patriarch);
     	assertEquals(10, patriarch.getX1());
@@ -202,11 +196,9 @@ final class TestEscherGraphics {
     	//  but not of their anchors
     	s1.setCoordinates(2, 3, 1021, 242);
 
-    	baos = new ByteArrayOutputStream();
-    	workbook.write(baos);
-    	workbook = new HSSFWorkbook(new ByteArrayInputStream(baos.toByteArray()));
-    	s = workbook.getSheetAt(0);
-    	patriarch = s.getDrawingPatriarch();
+		workbook = writeOutAndReadBack(workbook);
+		s = workbook.getSheetAt(0);
+		patriarch = s.getDrawingPatriarch();
 
     	assertNotNull(patriarch);
     	assertEquals(10, patriarch.getX1());
@@ -254,12 +246,9 @@ final class TestEscherGraphics {
     	assertEquals(3, patriarch.getChildren().size());
 
 
-    	baos = new ByteArrayOutputStream();
-    	workbook.write(baos);
-    	workbook = new HSSFWorkbook(new ByteArrayInputStream(baos.toByteArray()));
-    	s = workbook.getSheetAt(0);
-
-    	patriarch = s.getDrawingPatriarch();
+		workbook = writeOutAndReadBack(workbook);
+		s = workbook.getSheetAt(0);
+		patriarch = s.getDrawingPatriarch();
 
     	assertNotNull(patriarch);
     	assertEquals(10, patriarch.getX1());
diff --git a/poi/src/test/java/org/apache/poi/hssf/usermodel/TestHSSFPicture.java b/poi/src/test/java/org/apache/poi/hssf/usermodel/TestHSSFPicture.java
index b2a793f972..5e99f213f2 100644
--- a/poi/src/test/java/org/apache/poi/hssf/usermodel/TestHSSFPicture.java
+++ b/poi/src/test/java/org/apache/poi/hssf/usermodel/TestHSSFPicture.java
@@ -47,6 +47,7 @@ final class TestHSSFPicture extends BaseTestPicture {
         super(HSSFITestDataProvider.instance);
     }
 
+    @Override
     protected Picture getPictureShape(Drawing<?> pat, int picIdx) {
         return (Picture)((HSSFPatriarch)pat).getChildren().get(picIdx);
     }
diff --git a/poi/src/test/java/org/apache/poi/hssf/usermodel/TestHSSFWorkbook.java b/poi/src/test/java/org/apache/poi/hssf/usermodel/TestHSSFWorkbook.java
index ac4f32cb0e..3110783837 100644
--- a/poi/src/test/java/org/apache/poi/hssf/usermodel/TestHSSFWorkbook.java
+++ b/poi/src/test/java/org/apache/poi/hssf/usermodel/TestHSSFWorkbook.java
@@ -28,8 +28,6 @@ import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 import static org.junit.jupiter.api.Assertions.fail;
 
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.FileOutputStream;
@@ -41,6 +39,7 @@ import java.util.List;
 import java.util.Map;
 import java.util.function.Supplier;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.POIDataSamples;
 import org.apache.poi.ddf.EscherBSERecord;
 import org.apache.poi.hpsf.ClassID;
@@ -72,6 +71,7 @@ import org.apache.poi.ss.usermodel.Workbook;
 import org.apache.poi.ss.util.CellRangeAddress;
 import org.apache.poi.util.IOUtils;
 import org.apache.poi.util.TempFile;
+import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.CsvSource;
@@ -554,21 +554,17 @@ public final class TestHSSFWorkbook extends BaseTestWorkbook {
      */
     @Test
     void bug47920() throws IOException {
-        POIFSFileSystem fs1 = new POIFSFileSystem(samples.openResourceAsStream("47920.xls"));
-        HSSFWorkbook wb = new HSSFWorkbook(fs1);
-        ClassID clsid1 = fs1.getRoot().getStorageClsid();
-
-        ByteArrayOutputStream out = new ByteArrayOutputStream(4096);
-        wb.write(out);
-        byte[] bytes = out.toByteArray();
-        POIFSFileSystem fs2 = new POIFSFileSystem(new ByteArrayInputStream(bytes));
-        ClassID clsid2 = fs2.getRoot().getStorageClsid();
-
-        assertEquals(clsid1, clsid2);
-
-        fs2.close();
-        wb.close();
-        fs1.close();
+        try (POIFSFileSystem fs1 = new POIFSFileSystem(samples.openResourceAsStream("47920.xls"));
+             HSSFWorkbook wb = new HSSFWorkbook(fs1)) {
+            ClassID clsid1 = fs1.getRoot().getStorageClsid();
+
+            UnsynchronizedByteArrayOutputStream out = new UnsynchronizedByteArrayOutputStream(4096);
+            wb.write(out);
+            try (POIFSFileSystem fs2 = new POIFSFileSystem(out.toInputStream())) {
+                ClassID clsid2 = fs2.getRoot().getStorageClsid();
+                assertEquals(clsid1, clsid2);
+            }
+        }
     }
 
     /**
@@ -582,8 +578,7 @@ public final class TestHSSFWorkbook extends BaseTestWorkbook {
         "testEXCEL_95.xls,BIFF5"
     })
     void helpfulExceptionOnOldFiles(String file, String format) throws Exception {
-        POIDataSamples xlsData = samples;
-        try (InputStream is = xlsData.openResourceAsStream(file)) {
+        try (InputStream is = samples.openResourceAsStream(file)) {
             OldExcelFormatException e = assertThrows(OldExcelFormatException.class, () -> new HSSFWorkbook(is),
                 "Shouldn't be able to load an Excel " + format + " file");
             assertContains(e.getMessage(), format);
@@ -978,7 +973,7 @@ public final class TestHSSFWorkbook extends BaseTestWorkbook {
         assertNotNull(name);
         assertEquals("ASheet!A1", name.getRefersToFormula());
 
-		ByteArrayOutputStream stream = new ByteArrayOutputStream();
+		UnsynchronizedByteArrayOutputStream stream = new UnsynchronizedByteArrayOutputStream();
 		wb.write(stream);
 
 		assertSheetOrder(wb, "Sheet1", "Sheet2", "Sheet3", "ASheet");
@@ -989,15 +984,15 @@ public final class TestHSSFWorkbook extends BaseTestWorkbook {
 		assertSheetOrder(wb, "Sheet1", "Sheet3", "ASheet");
 		assertEquals("ASheet!A1", name.getRefersToFormula());
 
-		ByteArrayOutputStream stream2 = new ByteArrayOutputStream();
+		UnsynchronizedByteArrayOutputStream stream2 = new UnsynchronizedByteArrayOutputStream();
 		wb.write(stream2);
 
 		assertSheetOrder(wb, "Sheet1", "Sheet3", "ASheet");
 		assertEquals("ASheet!A1", name.getRefersToFormula());
 
-		HSSFWorkbook wb2 = new HSSFWorkbook(new ByteArrayInputStream(stream.toByteArray()));
+		HSSFWorkbook wb2 = new HSSFWorkbook(stream.toInputStream());
 		expectName(wb2, nameName, "ASheet!A1");
-		HSSFWorkbook wb3 = new HSSFWorkbook(new ByteArrayInputStream(stream2.toByteArray()));
+		HSSFWorkbook wb3 = new HSSFWorkbook(stream2.toInputStream());
 		expectName(wb3, nameName, "ASheet!A1");
 		wb3.close();
 		wb2.close();
@@ -1078,7 +1073,7 @@ public final class TestHSSFWorkbook extends BaseTestWorkbook {
 
     private void writeAndCloseWorkbook(Workbook workbook, File file)
     throws IOException {
-        final ByteArrayOutputStream bytesOut = new ByteArrayOutputStream();
+        final UnsynchronizedByteArrayOutputStream bytesOut = new UnsynchronizedByteArrayOutputStream();
         workbook.write(bytesOut);
         workbook.close();
 
@@ -1183,7 +1178,8 @@ public final class TestHSSFWorkbook extends BaseTestWorkbook {
         }
     }
 
-    void createDrawing() throws Exception {
+    @Disabled
+    void createDrawing() {
         // the dimensions for this image are different than for XSSF and SXSSF
     }
 }
diff --git a/poi/src/test/java/org/apache/poi/hssf/usermodel/TestOLE2Embeding.java b/poi/src/test/java/org/apache/poi/hssf/usermodel/TestOLE2Embeding.java
index 1183c5f6b5..60b15c8061 100644
--- a/poi/src/test/java/org/apache/poi/hssf/usermodel/TestOLE2Embeding.java
+++ b/poi/src/test/java/org/apache/poi/hssf/usermodel/TestOLE2Embeding.java
@@ -21,12 +21,11 @@ import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.util.List;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.POIDataSamples;
 import org.apache.poi.hssf.HSSFTestDataSamples;
 import org.apache.poi.poifs.filesystem.DirectoryNode;
@@ -60,73 +59,70 @@ final class TestOLE2Embeding {
 
     @Test
     void testReallyEmbedSomething() throws Exception {
-    	HSSFWorkbook wb1 = new HSSFWorkbook();
-    	HSSFSheet sheet = wb1.createSheet();
-    	HSSFPatriarch patriarch = sheet.createDrawingPatriarch();
-
-    	byte[] pictureData = HSSFTestDataSamples.getTestDataFileContent("logoKarmokar4.png");
-    	byte[] picturePPT = POIDataSamples.getSlideShowInstance().readFile("clock.jpg");
-    	int imgIdx = wb1.addPicture(pictureData, HSSFWorkbook.PICTURE_TYPE_PNG);
-    	POIFSFileSystem pptPoifs = getSamplePPT();
-    	int pptIdx = wb1.addOlePackage(pptPoifs, "Sample-PPT", "sample.ppt", "sample.ppt");
-    	POIFSFileSystem xlsPoifs = getSampleXLS();
-    	int imgPPT = wb1.addPicture(picturePPT, HSSFWorkbook.PICTURE_TYPE_JPEG);
-    	int xlsIdx = wb1.addOlePackage(xlsPoifs, "Sample-XLS", "sample.xls", "sample.xls");
-    	int txtIdx = wb1.addOlePackage(getSampleTXT(), "Sample-TXT", "sample.txt", "sample.txt");
-
-        int rowoffset = 5;
-        int coloffset = 5;
-
-        CreationHelper ch = wb1.getCreationHelper();
-        HSSFClientAnchor anchor = (HSSFClientAnchor)ch.createClientAnchor();
-        anchor.setAnchor((short)(2+coloffset), 1+rowoffset, 0, 0, (short)(3+coloffset), 5+rowoffset, 0, 0);
-        anchor.setAnchorType(AnchorType.DONT_MOVE_AND_RESIZE);
-
-        patriarch.createObjectData(anchor, pptIdx, imgPPT);
-
-        anchor = (HSSFClientAnchor)ch.createClientAnchor();
-        anchor.setAnchor((short)(5+coloffset), 1+rowoffset, 0, 0, (short)(6+coloffset), 5+rowoffset, 0, 0);
-        anchor.setAnchorType(AnchorType.DONT_MOVE_AND_RESIZE);
-
-        patriarch.createObjectData(anchor, xlsIdx, imgIdx);
-
-        anchor = (HSSFClientAnchor)ch.createClientAnchor();
-        anchor.setAnchor((short)(3+coloffset), 10+rowoffset, 0, 0, (short)(5+coloffset), 11+rowoffset, 0, 0);
-        anchor.setAnchorType(AnchorType.DONT_MOVE_AND_RESIZE);
-
-        patriarch.createObjectData(anchor, txtIdx, imgIdx);
-
-        anchor = (HSSFClientAnchor)ch.createClientAnchor();
-        anchor.setAnchor((short)(1+coloffset), -2+rowoffset, 0, 0, (short)(7+coloffset), 14+rowoffset, 0, 0);
-        anchor.setAnchorType(AnchorType.DONT_MOVE_AND_RESIZE);
-
-        HSSFSimpleShape circle = patriarch.createSimpleShape(anchor);
-        circle.setShapeType(HSSFSimpleShape.OBJECT_TYPE_OVAL);
-        circle.setNoFill(true);
-
-        HSSFWorkbook wb2 = HSSFTestDataSamples.writeOutAndReadBack(wb1);
-        wb1.close();
-
-        ByteArrayOutputStream bos = new ByteArrayOutputStream();
-        HSSFObjectData od = wb2.getAllEmbeddedObjects().get(0);
-        Ole10Native ole10 = Ole10Native.createFromEmbeddedOleObject((DirectoryNode)od.getDirectory());
-        bos.reset();
-        pptPoifs.writeFilesystem(bos);
-        assertArrayEquals(ole10.getDataBuffer(), bos.toByteArray());
-
-        od = wb2.getAllEmbeddedObjects().get(1);
-        ole10 = Ole10Native.createFromEmbeddedOleObject((DirectoryNode)od.getDirectory());
-        bos.reset();
-        xlsPoifs.writeFilesystem(bos);
-        assertArrayEquals(ole10.getDataBuffer(), bos.toByteArray());
-
-        od = wb2.getAllEmbeddedObjects().get(2);
-        ole10 = Ole10Native.createFromEmbeddedOleObject((DirectoryNode)od.getDirectory());
-        assertArrayEquals(ole10.getDataBuffer(), getSampleTXT());
-
-        xlsPoifs.close();
-        pptPoifs.close();
-        wb2.close();
+    	try (HSSFWorkbook wb1 = new HSSFWorkbook();
+             POIFSFileSystem pptPoifs = getSamplePPT();
+             POIFSFileSystem xlsPoifs = getSampleXLS()) {
+            HSSFSheet sheet = wb1.createSheet();
+            HSSFPatriarch patriarch = sheet.createDrawingPatriarch();
+
+            byte[] pictureData = HSSFTestDataSamples.getTestDataFileContent("logoKarmokar4.png");
+            byte[] picturePPT = POIDataSamples.getSlideShowInstance().readFile("clock.jpg");
+            int imgIdx = wb1.addPicture(pictureData, HSSFWorkbook.PICTURE_TYPE_PNG);
+
+            int pptIdx = wb1.addOlePackage(pptPoifs, "Sample-PPT", "sample.ppt", "sample.ppt");
+            int imgPPT = wb1.addPicture(picturePPT, HSSFWorkbook.PICTURE_TYPE_JPEG);
+            int xlsIdx = wb1.addOlePackage(xlsPoifs, "Sample-XLS", "sample.xls", "sample.xls");
+            int txtIdx = wb1.addOlePackage(getSampleTXT(), "Sample-TXT", "sample.txt", "sample.txt");
+
+            int rowoffset = 5;
+            int coloffset = 5;
+
+            CreationHelper ch = wb1.getCreationHelper();
+            HSSFClientAnchor anchor = (HSSFClientAnchor) ch.createClientAnchor();
+            anchor.setAnchor((short) (2 + coloffset), 1 + rowoffset, 0, 0, (short) (3 + coloffset), 5 + rowoffset, 0, 0);
+            anchor.setAnchorType(AnchorType.DONT_MOVE_AND_RESIZE);
+
+            patriarch.createObjectData(anchor, pptIdx, imgPPT);
+
+            anchor = (HSSFClientAnchor) ch.createClientAnchor();
+            anchor.setAnchor((short) (5 + coloffset), 1 + rowoffset, 0, 0, (short) (6 + coloffset), 5 + rowoffset, 0, 0);
+            anchor.setAnchorType(AnchorType.DONT_MOVE_AND_RESIZE);
+
+            patriarch.createObjectData(anchor, xlsIdx, imgIdx);
+
+            anchor = (HSSFClientAnchor) ch.createClientAnchor();
+            anchor.setAnchor((short) (3 + coloffset), 10 + rowoffset, 0, 0, (short) (5 + coloffset), 11 + rowoffset, 0, 0);
+            anchor.setAnchorType(AnchorType.DONT_MOVE_AND_RESIZE);
+
+            patriarch.createObjectData(anchor, txtIdx, imgIdx);
+
+            anchor = (HSSFClientAnchor) ch.createClientAnchor();
+            anchor.setAnchor((short) (1 + coloffset), -2 + rowoffset, 0, 0, (short) (7 + coloffset), 14 + rowoffset, 0, 0);
+            anchor.setAnchorType(AnchorType.DONT_MOVE_AND_RESIZE);
+
+            HSSFSimpleShape circle = patriarch.createSimpleShape(anchor);
+            circle.setShapeType(HSSFSimpleShape.OBJECT_TYPE_OVAL);
+            circle.setNoFill(true);
+
+            try (HSSFWorkbook wb2 = HSSFTestDataSamples.writeOutAndReadBack(wb1)) {
+                UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream();
+                HSSFObjectData od = wb2.getAllEmbeddedObjects().get(0);
+                Ole10Native ole10 = Ole10Native.createFromEmbeddedOleObject((DirectoryNode) od.getDirectory());
+                bos.reset();
+                pptPoifs.writeFilesystem(bos);
+                assertArrayEquals(ole10.getDataBuffer(), bos.toByteArray());
+
+                od = wb2.getAllEmbeddedObjects().get(1);
+                ole10 = Ole10Native.createFromEmbeddedOleObject((DirectoryNode) od.getDirectory());
+                bos.reset();
+                xlsPoifs.writeFilesystem(bos);
+                assertArrayEquals(ole10.getDataBuffer(), bos.toByteArray());
+
+                od = wb2.getAllEmbeddedObjects().get(2);
+                ole10 = Ole10Native.createFromEmbeddedOleObject((DirectoryNode) od.getDirectory());
+                assertArrayEquals(ole10.getDataBuffer(), getSampleTXT());
+            }
+        }
     }
 
     static POIFSFileSystem getSamplePPT() throws IOException {
@@ -139,15 +135,15 @@ final class TestOLE2Embeding {
     }
 
     static POIFSFileSystem getSampleXLS() throws IOException {
-        HSSFWorkbook wb = new HSSFWorkbook();
-        HSSFSheet sheet = wb.createSheet();
-        sheet.createRow(5).createCell(2).setCellValue("yo dawg i herd you like embeddet objekts, so we put a ole in your ole so you can save a file while you save a file");
+        UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream();
+        try (HSSFWorkbook wb = new HSSFWorkbook()) {
+            HSSFSheet sheet = wb.createSheet();
+            sheet.createRow(5).createCell(2).setCellValue("yo dawg i herd you like embeddet objekts, so we put a ole in your ole so you can save a file while you save a file");
 
-    	ByteArrayOutputStream bos = new ByteArrayOutputStream();
-    	wb.write(bos);
-    	wb.close();
+            wb.write(bos);
+        }
 
-        return new POIFSFileSystem(new ByteArrayInputStream(bos.toByteArray()));
+        return new POIFSFileSystem(bos.toInputStream());
     }
 
     static byte[] getSampleTXT() {
diff --git a/poi/src/test/java/org/apache/poi/hssf/usermodel/TestPOIFSProperties.java b/poi/src/test/java/org/apache/poi/hssf/usermodel/TestPOIFSProperties.java
index 6d62955f0c..5ff7c4e5ca 100644
--- a/poi/src/test/java/org/apache/poi/hssf/usermodel/TestPOIFSProperties.java
+++ b/poi/src/test/java/org/apache/poi/hssf/usermodel/TestPOIFSProperties.java
@@ -21,11 +21,14 @@ import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 
 import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 
-import org.apache.poi.hpsf.*;
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
+import org.apache.poi.hpsf.NoPropertySetStreamException;
+import org.apache.poi.hpsf.PropertySetFactory;
+import org.apache.poi.hpsf.SummaryInformation;
+import org.apache.poi.hpsf.WritingNotSupportedException;
 import org.apache.poi.hssf.HSSFTestDataSamples;
 import org.apache.poi.poifs.filesystem.POIFSFileSystem;
 import org.apache.poi.util.HexDump;
@@ -38,12 +41,11 @@ class TestPOIFSProperties {
     private static final String title = "Testing POIFS properties";
 
     @Test
-    void testFail() throws Exception {
-        ByteArrayOutputStream out = new ByteArrayOutputStream();
-        { // read the workbook, adjust the SummaryInformation and write the data to a byte array
-            POIFSFileSystem fs = openFileSystem();
-
-            HSSFWorkbook wb = new HSSFWorkbook(fs);
+    void testFail() throws IOException, NoPropertySetStreamException, WritingNotSupportedException {
+        UnsynchronizedByteArrayOutputStream out = new UnsynchronizedByteArrayOutputStream();
+        // read the workbook, adjust the SummaryInformation and write the data to a byte array
+        try (POIFSFileSystem fs = openFileSystem();
+             HSSFWorkbook wb = new HSSFWorkbook(fs)) {
 
             //set POIFS properties after constructing HSSFWorkbook
             //(a piece of code that used to work up to POI 3.0.2)
@@ -51,8 +53,6 @@ class TestPOIFSProperties {
 
             //save the workbook and read the property
             wb.write(out);
-            out.close();
-            wb.close();
         }
 
         // process the byte array
@@ -61,18 +61,16 @@ class TestPOIFSProperties {
 
     @Test
     void testOK() throws Exception {
-        ByteArrayOutputStream out = new ByteArrayOutputStream();
-        { // read the workbook, adjust the SummaryInformation and write the data to a byte array
-            POIFSFileSystem fs = openFileSystem();
+        UnsynchronizedByteArrayOutputStream out = new UnsynchronizedByteArrayOutputStream();
+        // read the workbook, adjust the SummaryInformation and write the data to a byte array
+        try (POIFSFileSystem fs = openFileSystem()) {
 
             //set POIFS properties before constructing HSSFWorkbook
             setTitle(fs);
 
-            HSSFWorkbook wb = new HSSFWorkbook(fs);
-
-            wb.write(out);
-            out.close();
-            wb.close();
+            try (HSSFWorkbook wb = new HSSFWorkbook(fs)) {
+                wb.write(out);
+            }
         }
 
         // process the byte array
@@ -80,13 +78,12 @@ class TestPOIFSProperties {
     }
 
     private POIFSFileSystem openFileSystem() throws IOException {
-        InputStream is = HSSFTestDataSamples.openSampleFileStream("Simple.xls");
-        POIFSFileSystem fs = new POIFSFileSystem(is);
-        is.close();
-        return fs;
+        try (InputStream is = HSSFTestDataSamples.openSampleFileStream("Simple.xls")) {
+            return new POIFSFileSystem(is);
+        }
     }
 
-    private void setTitle(POIFSFileSystem fs) throws NoPropertySetStreamException, MarkUnsupportedException, IOException, WritingNotSupportedException {
+    private void setTitle(POIFSFileSystem fs) throws NoPropertySetStreamException, IOException, WritingNotSupportedException {
         SummaryInformation summary1 = (SummaryInformation) PropertySetFactory.create(fs.createDocumentInputStream(SummaryInformation.DEFAULT_STREAM_NAME));
         assertNotNull(summary1);
 
@@ -100,16 +97,15 @@ class TestPOIFSProperties {
         assertNotNull(summaryCheck);
     }
 
-    private void checkFromByteArray(byte[] bytes) throws IOException, NoPropertySetStreamException, MarkUnsupportedException {
+    private void checkFromByteArray(byte[] bytes) throws IOException, NoPropertySetStreamException {
         // on some environments in CI we see strange failures, let's verify that the size is exactly right
         // this can be removed again after the problem is identified
         assertEquals(5120, bytes.length, "Had: " + HexDump.toHex(bytes));
 
-        POIFSFileSystem fs2 = new POIFSFileSystem(new ByteArrayInputStream(bytes));
-        SummaryInformation summary2 = (SummaryInformation) PropertySetFactory.create(fs2.createDocumentInputStream(SummaryInformation.DEFAULT_STREAM_NAME));
-        assertNotNull(summary2);
-
-        assertEquals(title, summary2.getTitle());
-        fs2.close();
+        try (POIFSFileSystem fs2 = new POIFSFileSystem(new ByteArrayInputStream(bytes))) {
+            SummaryInformation summary2 = (SummaryInformation) PropertySetFactory.create(fs2.createDocumentInputStream(SummaryInformation.DEFAULT_STREAM_NAME));
+            assertNotNull(summary2);
+            assertEquals(title, summary2.getTitle());
+        }
     }
 }
diff --git a/poi/src/test/java/org/apache/poi/poifs/crypt/TestXorEncryption.java b/poi/src/test/java/org/apache/poi/poifs/crypt/TestXorEncryption.java
index 2bca550236..3250bc0307 100644
--- a/poi/src/test/java/org/apache/poi/poifs/crypt/TestXorEncryption.java
+++ b/poi/src/test/java/org/apache/poi/poifs/crypt/TestXorEncryption.java
@@ -17,12 +17,12 @@
 
 package org.apache.poi.poifs.crypt;
 
+import static org.apache.poi.hssf.HSSFTestDataSamples.getSampleFile;
+import static org.apache.poi.hssf.HSSFTestDataSamples.writeOutAndReadBack;
 import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.core.IsEqual.equalTo;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.IOException;
 
@@ -37,9 +37,6 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 class TestXorEncryption {
-
-    private static final HSSFTestDataSamples samples = new HSSFTestDataSamples();
-
     @Test
     void testXorEncryption() {
         // Xor-Password: abc
@@ -56,10 +53,9 @@ class TestXorEncryption {
         assertThat(xorArrExp, equalTo(xorArrAct));
     }
 
-    @SuppressWarnings("static-access")
     @Test
     void testUserFile() throws IOException {
-        File f = samples.getSampleFile("xor-encryption-abc.xls");
+        File f = getSampleFile("xor-encryption-abc.xls");
         Biff8EncryptionKey.setCurrentUserPassword("abc");
         try (POIFSFileSystem fs = new POIFSFileSystem(f, true);
              HSSFWorkbook hwb = new HSSFWorkbook(fs.getRoot(), true)) {
@@ -75,16 +71,14 @@ class TestXorEncryption {
     @Test
     @Disabled("currently not supported")
     void encrypt() throws IOException {
-        ByteArrayOutputStream bos = new ByteArrayOutputStream();
         try {
             try (HSSFWorkbook hwb = HSSFTestDataSamples.openSampleWorkbook("SampleSS.xls")) {
                 Biff8EncryptionKey.setCurrentUserPassword("abc");
                 hwb.getInternalWorkbook().getWorkbookRecordList()
                     .add(1, new FilePassRecord(EncryptionMode.xor));
-                hwb.write(bos);
-            }
-            try (HSSFWorkbook hwb = new HSSFWorkbook(new ByteArrayInputStream(bos.toByteArray()))) {
-                assertEquals(3, hwb.getNumberOfSheets());
+                try (HSSFWorkbook hwb2 = writeOutAndReadBack(hwb)) {
+                    assertEquals(3, hwb2.getNumberOfSheets());
+                }
             }
         } finally {
             Biff8EncryptionKey.setCurrentUserPassword(null);
diff --git a/poi/src/test/java/org/apache/poi/poifs/dev/TestPOIFSDump.java b/poi/src/test/java/org/apache/poi/poifs/dev/TestPOIFSDump.java
index 1fa1802bea..4482607e62 100644
--- a/poi/src/test/java/org/apache/poi/poifs/dev/TestPOIFSDump.java
+++ b/poi/src/test/java/org/apache/poi/poifs/dev/TestPOIFSDump.java
@@ -34,7 +34,7 @@ import org.apache.poi.poifs.filesystem.NotOLE2FileException;
 import org.apache.poi.poifs.filesystem.OfficeXmlFileException;
 import org.apache.poi.poifs.filesystem.POIFSFileSystem;
 import org.apache.poi.poifs.property.PropertyTable;
-import org.apache.poi.util.NullPrintStream;
+import org.apache.commons.io.output.NullPrintStream;
 import org.apache.poi.util.TempFile;
 import org.junit.jupiter.api.AfterAll;
 import org.junit.jupiter.api.AfterEach;
@@ -150,7 +150,7 @@ public class TestPOIFSDump {
     }
 
     @Test
-    void testMainNoArgs() throws Exception {
+    void testMainNoArgs() {
         SecurityManager sm = System.getSecurityManager();
         try {
             System.setSecurityManager(new SecurityManager() {
diff --git a/poi/src/test/java/org/apache/poi/poifs/filesystem/TestDocument.java b/poi/src/test/java/org/apache/poi/poifs/filesystem/TestDocument.java
index 15edc14e92..4994d5db98 100644
--- a/poi/src/test/java/org/apache/poi/poifs/filesystem/TestDocument.java
+++ b/poi/src/test/java/org/apache/poi/poifs/filesystem/TestDocument.java
@@ -21,14 +21,15 @@ import static org.apache.poi.poifs.common.POIFSConstants.LARGER_BIG_BLOCK_SIZE;
 import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertSame;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.nio.ByteBuffer;
 import java.util.stream.IntStream;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.poifs.property.DocumentProperty;
 import org.apache.poi.poifs.storage.RawDataUtil;
 import org.apache.poi.util.IOUtils;
@@ -67,7 +68,7 @@ class TestDocument {
             // verify that output is correct
             POIFSDocument document = checkDocument(poifs, LARGER_BIG_BLOCK_SIZE + 1);
             DocumentProperty property = document.getDocumentProperty();
-            ByteArrayOutputStream stream = new ByteArrayOutputStream();
+            UnsynchronizedByteArrayOutputStream stream = new UnsynchronizedByteArrayOutputStream();
 
             property.writeData(stream);
             byte[] output = stream.toByteArray();
@@ -111,7 +112,7 @@ class TestDocument {
     private static byte[] checkValues(final int blockCountExp, POIFSDocument document, byte[] input) throws IOException {
         assertNotNull(document);
         assertNotNull(document.getDocumentProperty().getDocument());
-        assertEquals(document, document.getDocumentProperty().getDocument());
+        assertSame(document, document.getDocumentProperty().getDocument());
 
         ByteArrayInputStream bis = new ByteArrayInputStream(input);
 
@@ -134,7 +135,7 @@ class TestDocument {
 
         assertEquals(blockCountExp, blockCountAct);
 
-        ByteArrayOutputStream stream = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream stream = new UnsynchronizedByteArrayOutputStream();
         try (DocumentInputStream dis = document.getFileSystem().createDocumentInputStream(
                 document.getDocumentProperty().getName())) {
             IOUtils.copy(dis, stream);
diff --git a/poi/src/test/java/org/apache/poi/poifs/filesystem/TestDocumentOutputStream.java b/poi/src/test/java/org/apache/poi/poifs/filesystem/TestDocumentOutputStream.java
index d2815e0254..95133ff478 100644
--- a/poi/src/test/java/org/apache/poi/poifs/filesystem/TestDocumentOutputStream.java
+++ b/poi/src/test/java/org/apache/poi/poifs/filesystem/TestDocumentOutputStream.java
@@ -22,10 +22,10 @@ import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.fail;
 
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.util.Arrays;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.util.IOUtils;
 import org.junit.jupiter.api.Test;
 
@@ -46,7 +46,7 @@ final class TestDocumentOutputStream {
 
             try {
                 for (byte b : expected) {
-                    dstream.write((int)b);
+                    dstream.write(b);
                 }
             } catch (IOException ignored) {
                 fail("stream exhausted too early");
@@ -115,7 +115,7 @@ final class TestDocumentOutputStream {
             root.createDocument("foo", expected.length, l);
 
             try (DocumentInputStream is = root.createDocumentInputStream("foo")) {
-                final ByteArrayOutputStream bos = new ByteArrayOutputStream(expected.length);
+                final UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream(expected.length);
                 IOUtils.copy(is, bos);
                 assertArrayEquals(expected, bos.toByteArray());
             }
diff --git a/poi/src/test/java/org/apache/poi/poifs/filesystem/TestEmptyDocument.java b/poi/src/test/java/org/apache/poi/poifs/filesystem/TestEmptyDocument.java
index c594fb513d..ed08a1fa08 100644
--- a/poi/src/test/java/org/apache/poi/poifs/filesystem/TestEmptyDocument.java
+++ b/poi/src/test/java/org/apache/poi/poifs/filesystem/TestEmptyDocument.java
@@ -22,10 +22,10 @@ import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.util.stream.Stream;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.poi.util.IOUtils;
@@ -82,9 +82,9 @@ final class TestEmptyDocument {
 			DirectoryEntry dir = fs.getRoot();
 			emptyDoc.handle(dir);
 
-			ByteArrayOutputStream out = new ByteArrayOutputStream();
+			UnsynchronizedByteArrayOutputStream out = new UnsynchronizedByteArrayOutputStream();
 			fs.writeFilesystem(out);
-			assertDoesNotThrow(() -> new POIFSFileSystem(new ByteArrayInputStream(out.toByteArray())));
+			assertDoesNotThrow(() -> new POIFSFileSystem(out.toInputStream()));
 		}
 	}
 
@@ -92,7 +92,7 @@ final class TestEmptyDocument {
 	void testEmptyDocumentBug11744() throws Exception {
 		byte[] testData = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 };
 
-		ByteArrayOutputStream out = new ByteArrayOutputStream();
+		UnsynchronizedByteArrayOutputStream out = new UnsynchronizedByteArrayOutputStream();
 		try (POIFSFileSystem fs = new POIFSFileSystem()) {
 			fs.createDocument(new ByteArrayInputStream(new byte[0]), "Empty");
 			fs.createDocument(new ByteArrayInputStream(testData), "NotEmpty");
@@ -100,7 +100,7 @@ final class TestEmptyDocument {
 		}
 
 		// This line caused the error.
-		try (POIFSFileSystem fs = new POIFSFileSystem(new ByteArrayInputStream(out.toByteArray()))) {
+		try (POIFSFileSystem fs = new POIFSFileSystem(out.toInputStream())) {
 			DocumentEntry entry = (DocumentEntry) fs.getRoot().getEntry("Empty");
 			assertEquals(0, entry.getSize(), "Expected zero size");
 			byte[] actualReadbackData;
diff --git a/poi/src/test/java/org/apache/poi/poifs/filesystem/TestEntryUtils.java b/poi/src/test/java/org/apache/poi/poifs/filesystem/TestEntryUtils.java
index b85550cc15..e2abb090ab 100644
--- a/poi/src/test/java/org/apache/poi/poifs/filesystem/TestEntryUtils.java
+++ b/poi/src/test/java/org/apache/poi/poifs/filesystem/TestEntryUtils.java
@@ -24,12 +24,13 @@ import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
+import java.io.InputStream;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.junit.jupiter.api.Test;
 
 class TestEntryUtils {
@@ -101,51 +102,52 @@ class TestEntryUtils {
 
     @Test
     void testAreDocumentsIdentical() throws IOException {
-       POIFSFileSystem fs = new POIFSFileSystem();
-       DirectoryEntry dirA = fs.createDirectory("DirA");
-       DirectoryEntry dirB = fs.createDirectory("DirB");
+       try (POIFSFileSystem fs = new POIFSFileSystem()) {
+          DirectoryEntry dirA = fs.createDirectory("DirA");
+          DirectoryEntry dirB = fs.createDirectory("DirB");
 
-       DocumentEntry entryA1 = dirA.createDocument("Entry1", new ByteArrayInputStream(dataSmallA));
-       DocumentEntry entryA1b = dirA.createDocument("Entry1b", new ByteArrayInputStream(dataSmallA));
-       DocumentEntry entryA2 = dirA.createDocument("Entry2", new ByteArrayInputStream(dataSmallB));
-       DocumentEntry entryB1 = dirB.createDocument("Entry1", new ByteArrayInputStream(dataSmallA));
+          DocumentEntry entryA1 = dirA.createDocument("Entry1", new ByteArrayInputStream(dataSmallA));
+          DocumentEntry entryA1b = dirA.createDocument("Entry1b", new ByteArrayInputStream(dataSmallA));
+          DocumentEntry entryA2 = dirA.createDocument("Entry2", new ByteArrayInputStream(dataSmallB));
+          DocumentEntry entryB1 = dirB.createDocument("Entry1", new ByteArrayInputStream(dataSmallA));
 
 
-       // Names must match
-       assertNotEquals(entryA1.getName(), entryA1b.getName());
-       assertFalse(EntryUtils.areDocumentsIdentical(entryA1, entryA1b));
+          // Names must match
+          assertNotEquals(entryA1.getName(), entryA1b.getName());
+          assertFalse(EntryUtils.areDocumentsIdentical(entryA1, entryA1b));
 
-       // Contents must match
-       assertFalse(EntryUtils.areDocumentsIdentical(entryA1, entryA2));
+          // Contents must match
+          assertFalse(EntryUtils.areDocumentsIdentical(entryA1, entryA2));
 
-       // Parents don't matter if contents + names are the same
-       assertNotEquals(entryA1.getParent(), entryB1.getParent());
-       assertTrue(EntryUtils.areDocumentsIdentical(entryA1, entryB1));
+          // Parents don't matter if contents + names are the same
+          assertNotEquals(entryA1.getParent(), entryB1.getParent());
+          assertTrue(EntryUtils.areDocumentsIdentical(entryA1, entryB1));
 
 
-       // Can work with POIFS
-       ByteArrayOutputStream tmpO = new ByteArrayOutputStream();
-       fs.writeFilesystem(tmpO);
+          // Can work with POIFS
+          try (UnsynchronizedByteArrayOutputStream tmpO = new UnsynchronizedByteArrayOutputStream()) {
+             fs.writeFilesystem(tmpO);
 
-       ByteArrayInputStream tmpI = new ByteArrayInputStream(tmpO.toByteArray());
-       POIFSFileSystem nfs = new POIFSFileSystem(tmpI);
+             try (InputStream tmpI = tmpO.toInputStream();
+                  POIFSFileSystem nfs = new POIFSFileSystem(tmpI)) {
 
-       DirectoryEntry dN1 = (DirectoryEntry)nfs.getRoot().getEntry("DirA");
-       DirectoryEntry dN2 = (DirectoryEntry)nfs.getRoot().getEntry("DirB");
-       DocumentEntry eNA1 = (DocumentEntry)dN1.getEntry(entryA1.getName());
-       DocumentEntry eNA2 = (DocumentEntry)dN1.getEntry(entryA2.getName());
-       DocumentEntry eNB1 = (DocumentEntry)dN2.getEntry(entryB1.getName());
+                DirectoryEntry dN1 = (DirectoryEntry) nfs.getRoot().getEntry("DirA");
+                DirectoryEntry dN2 = (DirectoryEntry) nfs.getRoot().getEntry("DirB");
+                DocumentEntry eNA1 = (DocumentEntry) dN1.getEntry(entryA1.getName());
+                DocumentEntry eNA2 = (DocumentEntry) dN1.getEntry(entryA2.getName());
+                DocumentEntry eNB1 = (DocumentEntry) dN2.getEntry(entryB1.getName());
 
-       assertFalse(EntryUtils.areDocumentsIdentical(eNA1, eNA2));
-       assertTrue(EntryUtils.areDocumentsIdentical(eNA1, eNB1));
+                assertFalse(EntryUtils.areDocumentsIdentical(eNA1, eNA2));
+                assertTrue(EntryUtils.areDocumentsIdentical(eNA1, eNB1));
 
-       assertFalse(EntryUtils.areDocumentsIdentical(eNA1, entryA1b));
-       assertFalse(EntryUtils.areDocumentsIdentical(eNA1, entryA2));
+                assertFalse(EntryUtils.areDocumentsIdentical(eNA1, entryA1b));
+                assertFalse(EntryUtils.areDocumentsIdentical(eNA1, entryA2));
 
-       assertTrue(EntryUtils.areDocumentsIdentical(eNA1, entryA1));
-       assertTrue(EntryUtils.areDocumentsIdentical(eNA1, entryB1));
-       nfs.close();
-       fs.close();
+                assertTrue(EntryUtils.areDocumentsIdentical(eNA1, entryA1));
+                assertTrue(EntryUtils.areDocumentsIdentical(eNA1, entryB1));
+             }
+          }
+       }
     }
 
     @Test
diff --git a/poi/src/test/java/org/apache/poi/poifs/filesystem/TestFileSystemBugs.java b/poi/src/test/java/org/apache/poi/poifs/filesystem/TestFileSystemBugs.java
index ef504aca69..dd52a10a58 100644
--- a/poi/src/test/java/org/apache/poi/poifs/filesystem/TestFileSystemBugs.java
+++ b/poi/src/test/java/org/apache/poi/poifs/filesystem/TestFileSystemBugs.java
@@ -20,8 +20,6 @@ package org.apache.poi.poifs.filesystem;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.InputStream;
 import java.util.ArrayList;
 import java.util.HashMap;
@@ -29,6 +27,7 @@ import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.POIDataSamples;
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.Test;
@@ -141,11 +140,10 @@ final class TestFileSystemBugs {
         EntryUtils.copyNodes(root, dest);
 
         // Re-load
-        ByteArrayOutputStream baos = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
         root.getFileSystem().writeFilesystem(baos);
 
-        POIFSFileSystem read = new POIFSFileSystem(
-                new ByteArrayInputStream(baos.toByteArray()));
+        POIFSFileSystem read = new POIFSFileSystem(baos.toInputStream());
 
         // Check the structure matches
         checkSizes("/", read.getRoot(), entries);
diff --git a/poi/src/test/java/org/apache/poi/poifs/filesystem/TestOle10Native.java b/poi/src/test/java/org/apache/poi/poifs/filesystem/TestOle10Native.java
index 6becf23aa1..3a3f2fa8dc 100644
--- a/poi/src/test/java/org/apache/poi/poifs/filesystem/TestOle10Native.java
+++ b/poi/src/test/java/org/apache/poi/poifs/filesystem/TestOle10Native.java
@@ -23,7 +23,6 @@ import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
@@ -31,6 +30,7 @@ import java.util.ArrayList;
 import java.util.Iterator;
 import java.util.List;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.POIDataSamples;
 import org.apache.poi.util.IOUtils;
 import org.apache.poi.util.RecordFormatException;
@@ -62,25 +62,24 @@ class TestOle10Native {
         };
 
         for (File f : files) {
-            POIFSFileSystem fs = new POIFSFileSystem(f, true);
-            List<Entry> entries = new ArrayList<>();
-            findOle10(entries, fs.getRoot(), "/");
+            try (POIFSFileSystem fs = new POIFSFileSystem(f, true)) {
+                List<Entry> entries = new ArrayList<>();
+                findOle10(entries, fs.getRoot(), "/");
 
-            for (Entry e : entries) {
-                ByteArrayOutputStream bosExp = new ByteArrayOutputStream();
-                InputStream is = ((DirectoryNode)e.getParent()).createDocumentInputStream(e);
-                IOUtils.copy(is,bosExp);
-                is.close();
+                for (Entry e : entries) {
+                    UnsynchronizedByteArrayOutputStream bosExp = new UnsynchronizedByteArrayOutputStream();
+                    try (InputStream is = ((DirectoryNode) e.getParent()).createDocumentInputStream(e)) {
+                        IOUtils.copy(is, bosExp);
+                    }
 
-                Ole10Native ole = Ole10Native.createFromEmbeddedOleObject((DirectoryNode)e.getParent());
+                    Ole10Native ole = Ole10Native.createFromEmbeddedOleObject((DirectoryNode) e.getParent());
 
-                ByteArrayOutputStream bosAct = new ByteArrayOutputStream();
-                ole.writeOut(bosAct);
+                    UnsynchronizedByteArrayOutputStream bosAct = new UnsynchronizedByteArrayOutputStream();
+                    ole.writeOut(bosAct);
 
-                assertThat(bosExp.toByteArray(), equalTo(bosAct.toByteArray()));
+                    assertThat(bosExp.toByteArray(), equalTo(bosAct.toByteArray()));
+                }
             }
-
-            fs.close();
         }
     }
 
diff --git a/poi/src/test/java/org/apache/poi/poifs/filesystem/TestPOIFSFileSystem.java b/poi/src/test/java/org/apache/poi/poifs/filesystem/TestPOIFSFileSystem.java
index c644fb1c60..db6a062872 100644
--- a/poi/src/test/java/org/apache/poi/poifs/filesystem/TestPOIFSFileSystem.java
+++ b/poi/src/test/java/org/apache/poi/poifs/filesystem/TestPOIFSFileSystem.java
@@ -23,13 +23,13 @@ import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.UnsupportedEncodingException;
 import java.nio.ByteBuffer;
 import java.util.HashMap;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.POIDataSamples;
 import org.apache.poi.hpsf.NoPropertySetStreamException;
 import org.apache.poi.hpsf.Property;
@@ -44,7 +44,6 @@ import org.apache.poi.util.IOUtils;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.CsvSource;
-import org.junit.jupiter.params.provider.ValueSource;
 
 /**
  * Tests for the older OPOIFS-based POIFSFileSystem
@@ -147,7 +146,7 @@ final class TestPOIFSFileSystem {
 		try (POIFSFileSystem fs = new POIFSFileSystem(_samples.openResourceAsStream(file))) {
 
 			// Write it into a temp output array
-			ByteArrayOutputStream baos = new ByteArrayOutputStream();
+			UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
 			fs.writeFilesystem(baos);
 
 			// Check sizes
@@ -186,7 +185,7 @@ final class TestPOIFSFileSystem {
 	         "BIG", new ByteArrayInputStream(hugeStream)
 	   );
 
-	   ByteArrayOutputStream baos = new ByteArrayOutputStream();
+	   UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
 	   fs.writeFilesystem(baos);
 	   byte[] fsData = baos.toByteArray();
 
diff --git a/poi/src/test/java/org/apache/poi/poifs/filesystem/TestPOIFSStream.java b/poi/src/test/java/org/apache/poi/poifs/filesystem/TestPOIFSStream.java
index 2a2a8122d1..430cd8e5d2 100644
--- a/poi/src/test/java/org/apache/poi/poifs/filesystem/TestPOIFSStream.java
+++ b/poi/src/test/java/org/apache/poi/poifs/filesystem/TestPOIFSStream.java
@@ -17,6 +17,7 @@
 
 package org.apache.poi.poifs.filesystem;
 
+import static org.apache.poi.POIDataSamples.writeOutAndReadBack;
 import static org.hamcrest.CoreMatchers.hasItem;
 import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.core.IsEqual.equalTo;
@@ -26,21 +27,28 @@ import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertNull;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.junit.jupiter.api.Assertions.fail;
 import static org.junit.jupiter.api.Assumptions.assumeTrue;
 
 import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
 import java.nio.ByteBuffer;
+import java.util.Arrays;
+import java.util.Collection;
 import java.util.Iterator;
+import java.util.List;
 import java.util.NoSuchElementException;
+import java.util.function.Function;
 
+import org.apache.commons.collections4.CollectionUtils;
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.POIDataSamples;
 import org.apache.poi.hpsf.DocumentSummaryInformation;
+import org.apache.poi.hpsf.NoPropertySetStreamException;
 import org.apache.poi.hpsf.PropertySet;
 import org.apache.poi.hpsf.PropertySetFactory;
 import org.apache.poi.hpsf.SummaryInformation;
@@ -55,6 +63,9 @@ import org.apache.poi.util.IOUtils;
 import org.apache.poi.util.TempFile;
 import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
 
 /**
  * Tests {@link POIFSStream}
@@ -67,26 +78,25 @@ final class TestPOIFSStream {
      */
     @Test
     void testReadTinyStream() throws Exception {
-        POIFSFileSystem fs = new POIFSFileSystem(_inst.getFile("BlockSize512.zvi"));
-
-        // 98 is actually the last block in a two block stream...
-        POIFSStream stream = new POIFSStream(fs, 98);
-        Iterator<ByteBuffer> i = stream.getBlockIterator();
-        assertTrue(i.hasNext());
-        ByteBuffer b = i.next();
-        assertFalse(i.hasNext());
-
-        // Check the contents
-        assertEquals((byte) 0x81, b.get());
-        assertEquals((byte) 0x00, b.get());
-        assertEquals((byte) 0x00, b.get());
-        assertEquals((byte) 0x00, b.get());
-        assertEquals((byte) 0x82, b.get());
-        assertEquals((byte) 0x00, b.get());
-        assertEquals((byte) 0x00, b.get());
-        assertEquals((byte) 0x00, b.get());
-
-        fs.close();
+        try (POIFSFileSystem fs = new POIFSFileSystem(_inst.getFile("BlockSize512.zvi"))) {
+
+            // 98 is actually the last block in a two block stream...
+            POIFSStream stream = new POIFSStream(fs, 98);
+            Iterator<ByteBuffer> i = stream.getBlockIterator();
+            assertTrue(i.hasNext());
+            ByteBuffer b = i.next();
+            assertFalse(i.hasNext());
+
+            // Check the contents
+            assertEquals((byte) 0x81, b.get());
+            assertEquals((byte) 0x00, b.get());
+            assertEquals((byte) 0x00, b.get());
+            assertEquals((byte) 0x00, b.get());
+            assertEquals((byte) 0x82, b.get());
+            assertEquals((byte) 0x00, b.get());
+            assertEquals((byte) 0x00, b.get());
+            assertEquals((byte) 0x00, b.get());
+        }
     }
 
     /**
@@ -94,38 +104,37 @@ final class TestPOIFSStream {
      */
     @Test
     void testReadShortStream() throws Exception {
-        POIFSFileSystem fs = new POIFSFileSystem(_inst.getFile("BlockSize512.zvi"));
-
-        // 97 -> 98 -> end
-        POIFSStream stream = new POIFSStream(fs, 97);
-        Iterator<ByteBuffer> i = stream.getBlockIterator();
-        assertTrue(i.hasNext());
-        ByteBuffer b97 = i.next();
-        assertTrue(i.hasNext());
-        ByteBuffer b98 = i.next();
-        assertFalse(i.hasNext());
-
-        // Check the contents of the 1st block
-        assertEquals((byte) 0x01, b97.get());
-        assertEquals((byte) 0x00, b97.get());
-        assertEquals((byte) 0x00, b97.get());
-        assertEquals((byte) 0x00, b97.get());
-        assertEquals((byte) 0x02, b97.get());
-        assertEquals((byte) 0x00, b97.get());
-        assertEquals((byte) 0x00, b97.get());
-        assertEquals((byte) 0x00, b97.get());
-
-        // Check the contents of the 2nd block
-        assertEquals((byte) 0x81, b98.get());
-        assertEquals((byte) 0x00, b98.get());
-        assertEquals((byte) 0x00, b98.get());
-        assertEquals((byte) 0x00, b98.get());
-        assertEquals((byte) 0x82, b98.get());
-        assertEquals((byte) 0x00, b98.get());
-        assertEquals((byte) 0x00, b98.get());
-        assertEquals((byte) 0x00, b98.get());
-
-        fs.close();
+        try (POIFSFileSystem fs = new POIFSFileSystem(_inst.getFile("BlockSize512.zvi"))) {
+
+            // 97 -> 98 -> end
+            POIFSStream stream = new POIFSStream(fs, 97);
+            Iterator<ByteBuffer> i = stream.getBlockIterator();
+            assertTrue(i.hasNext());
+            ByteBuffer b97 = i.next();
+            assertTrue(i.hasNext());
+            ByteBuffer b98 = i.next();
+            assertFalse(i.hasNext());
+
+            // Check the contents of the 1st block
+            assertEquals((byte) 0x01, b97.get());
+            assertEquals((byte) 0x00, b97.get());
+            assertEquals((byte) 0x00, b97.get());
+            assertEquals((byte) 0x00, b97.get());
+            assertEquals((byte) 0x02, b97.get());
+            assertEquals((byte) 0x00, b97.get());
+            assertEquals((byte) 0x00, b97.get());
+            assertEquals((byte) 0x00, b97.get());
+
+            // Check the contents of the 2nd block
+            assertEquals((byte) 0x81, b98.get());
+            assertEquals((byte) 0x00, b98.get());
+            assertEquals((byte) 0x00, b98.get());
+            assertEquals((byte) 0x00, b98.get());
+            assertEquals((byte) 0x82, b98.get());
+            assertEquals((byte) 0x00, b98.get());
+            assertEquals((byte) 0x00, b98.get());
+            assertEquals((byte) 0x00, b98.get());
+        }
     }
 
     /**
@@ -133,59 +142,58 @@ final class TestPOIFSStream {
      */
     @Test
     void testReadLongerStream() throws Exception {
-        POIFSFileSystem fs = new POIFSFileSystem(_inst.getFile("BlockSize512.zvi"));
+        try (POIFSFileSystem fs = new POIFSFileSystem(_inst.getFile("BlockSize512.zvi"))) {
 
-        ByteBuffer b0 = null;
-        ByteBuffer b1 = null;
-        ByteBuffer b22 = null;
+            ByteBuffer b0 = null;
+            ByteBuffer b1 = null;
+            ByteBuffer b22 = null;
 
-        // The stream at 0 has 23 blocks in it
-        POIFSStream stream = new POIFSStream(fs, 0);
-        Iterator<ByteBuffer> i = stream.getBlockIterator();
-        int count = 0;
-        while (i.hasNext()) {
-            ByteBuffer b = i.next();
-            if (count == 0) {
-                b0 = b;
-            }
-            if (count == 1) {
-                b1 = b;
-            }
-            if (count == 22) {
-                b22 = b;
-            }
+            // The stream at 0 has 23 blocks in it
+            POIFSStream stream = new POIFSStream(fs, 0);
+            Iterator<ByteBuffer> i = stream.getBlockIterator();
+            int count = 0;
+            while (i.hasNext()) {
+                ByteBuffer b = i.next();
+                if (count == 0) {
+                    b0 = b;
+                }
+                if (count == 1) {
+                    b1 = b;
+                }
+                if (count == 22) {
+                    b22 = b;
+                }
 
-            count++;
+                count++;
+            }
+            assertEquals(23, count);
+
+            // Check the contents
+            //  1st block is at 0
+            assertNotNull(b0);
+            assertEquals((byte) 0x9e, b0.get());
+            assertEquals((byte) 0x75, b0.get());
+            assertEquals((byte) 0x97, b0.get());
+            assertEquals((byte) 0xf6, b0.get());
+
+            //  2nd block is at 1
+            assertNotNull(b1);
+            assertEquals((byte) 0x86, b1.get());
+            assertEquals((byte) 0x09, b1.get());
+            assertEquals((byte) 0x22, b1.get());
+            assertEquals((byte) 0xfb, b1.get());
+
+            //  last block is at 89
+            assertNotNull(b22);
+            assertEquals((byte) 0xfe, b22.get());
+            assertEquals((byte) 0xff, b22.get());
+            assertEquals((byte) 0x00, b22.get());
+            assertEquals((byte) 0x00, b22.get());
+            assertEquals((byte) 0x05, b22.get());
+            assertEquals((byte) 0x01, b22.get());
+            assertEquals((byte) 0x02, b22.get());
+            assertEquals((byte) 0x00, b22.get());
         }
-        assertEquals(23, count);
-
-        // Check the contents
-        //  1st block is at 0
-        assertNotNull(b0);
-        assertEquals((byte) 0x9e, b0.get());
-        assertEquals((byte) 0x75, b0.get());
-        assertEquals((byte) 0x97, b0.get());
-        assertEquals((byte) 0xf6, b0.get());
-
-        //  2nd block is at 1
-        assertNotNull(b1);
-        assertEquals((byte) 0x86, b1.get());
-        assertEquals((byte) 0x09, b1.get());
-        assertEquals((byte) 0x22, b1.get());
-        assertEquals((byte) 0xfb, b1.get());
-
-        //  last block is at 89
-        assertNotNull(b22);
-        assertEquals((byte) 0xfe, b22.get());
-        assertEquals((byte) 0xff, b22.get());
-        assertEquals((byte) 0x00, b22.get());
-        assertEquals((byte) 0x00, b22.get());
-        assertEquals((byte) 0x05, b22.get());
-        assertEquals((byte) 0x01, b22.get());
-        assertEquals((byte) 0x02, b22.get());
-        assertEquals((byte) 0x00, b22.get());
-
-        fs.close();
     }
 
     /**
@@ -193,50 +201,48 @@ final class TestPOIFSStream {
      */
     @Test
     void testReadStream4096() throws Exception {
-        POIFSFileSystem fs = new POIFSFileSystem(_inst.getFile("BlockSize4096.zvi"));
-
-        // 0 -> 1 -> 2 -> end
-        POIFSStream stream = new POIFSStream(fs, 0);
-        Iterator<ByteBuffer> i = stream.getBlockIterator();
-        assertTrue(i.hasNext());
-        ByteBuffer b0 = i.next();
-        assertTrue(i.hasNext());
-        ByteBuffer b1 = i.next();
-        assertTrue(i.hasNext());
-        ByteBuffer b2 = i.next();
-        assertFalse(i.hasNext());
-
-        // Check the contents of the 1st block
-        assertEquals((byte) 0x9E, b0.get());
-        assertEquals((byte) 0x75, b0.get());
-        assertEquals((byte) 0x97, b0.get());
-        assertEquals((byte) 0xF6, b0.get());
-        assertEquals((byte) 0xFF, b0.get());
-        assertEquals((byte) 0x21, b0.get());
-        assertEquals((byte) 0xD2, b0.get());
-        assertEquals((byte) 0x11, b0.get());
-
-        // Check the contents of the 2nd block
-        assertEquals((byte) 0x00, b1.get());
-        assertEquals((byte) 0x00, b1.get());
-        assertEquals((byte) 0x03, b1.get());
-        assertEquals((byte) 0x00, b1.get());
-        assertEquals((byte) 0x00, b1.get());
-        assertEquals((byte) 0x00, b1.get());
-        assertEquals((byte) 0x00, b1.get());
-        assertEquals((byte) 0x00, b1.get());
-
-        // Check the contents of the 3rd block
-        assertEquals((byte) 0x6D, b2.get());
-        assertEquals((byte) 0x00, b2.get());
-        assertEquals((byte) 0x00, b2.get());
-        assertEquals((byte) 0x00, b2.get());
-        assertEquals((byte) 0x03, b2.get());
-        assertEquals((byte) 0x00, b2.get());
-        assertEquals((byte) 0x46, b2.get());
-        assertEquals((byte) 0x00, b2.get());
-
-        fs.close();
+        try (POIFSFileSystem fs = new POIFSFileSystem(_inst.getFile("BlockSize4096.zvi"))) {
+            // 0 -> 1 -> 2 -> end
+            POIFSStream stream = new POIFSStream(fs, 0);
+            Iterator<ByteBuffer> i = stream.getBlockIterator();
+            assertTrue(i.hasNext());
+            ByteBuffer b0 = i.next();
+            assertTrue(i.hasNext());
+            ByteBuffer b1 = i.next();
+            assertTrue(i.hasNext());
+            ByteBuffer b2 = i.next();
+            assertFalse(i.hasNext());
+
+            // Check the contents of the 1st block
+            assertEquals((byte) 0x9E, b0.get());
+            assertEquals((byte) 0x75, b0.get());
+            assertEquals((byte) 0x97, b0.get());
+            assertEquals((byte) 0xF6, b0.get());
+            assertEquals((byte) 0xFF, b0.get());
+            assertEquals((byte) 0x21, b0.get());
+            assertEquals((byte) 0xD2, b0.get());
+            assertEquals((byte) 0x11, b0.get());
+
+            // Check the contents of the 2nd block
+            assertEquals((byte) 0x00, b1.get());
+            assertEquals((byte) 0x00, b1.get());
+            assertEquals((byte) 0x03, b1.get());
+            assertEquals((byte) 0x00, b1.get());
+            assertEquals((byte) 0x00, b1.get());
+            assertEquals((byte) 0x00, b1.get());
+            assertEquals((byte) 0x00, b1.get());
+            assertEquals((byte) 0x00, b1.get());
+
+            // Check the contents of the 3rd block
+            assertEquals((byte) 0x6D, b2.get());
+            assertEquals((byte) 0x00, b2.get());
+            assertEquals((byte) 0x00, b2.get());
+            assertEquals((byte) 0x00, b2.get());
+            assertEquals((byte) 0x03, b2.get());
+            assertEquals((byte) 0x00, b2.get());
+            assertEquals((byte) 0x46, b2.get());
+            assertEquals((byte) 0x00, b2.get());
+        }
     }
 
     /**
@@ -244,35 +250,33 @@ final class TestPOIFSStream {
      */
     @Test
     void testReadFailsOnLoop() throws Exception {
-        POIFSFileSystem fs = new POIFSFileSystem(_inst.getFile("BlockSize512.zvi"));
-
-        // Hack the FAT so that it goes 0->1->2->0
-        fs.setNextBlock(0, 1);
-        fs.setNextBlock(1, 2);
-        fs.setNextBlock(2, 0);
-
-        // Now try to read
-        POIFSStream stream = new POIFSStream(fs, 0);
-        Iterator<ByteBuffer> i = stream.getBlockIterator();
-        assertTrue(i.hasNext());
+        try (POIFSFileSystem fs = new POIFSFileSystem(_inst.getFile("BlockSize512.zvi"))) {
+            // Hack the FAT so that it goes 0->1->2->0
+            fs.setNextBlock(0, 1);
+            fs.setNextBlock(1, 2);
+            fs.setNextBlock(2, 0);
 
-        // 1st read works
-        i.next();
-        assertTrue(i.hasNext());
+            // Now try to read
+            POIFSStream stream = new POIFSStream(fs, 0);
+            Iterator<ByteBuffer> i = stream.getBlockIterator();
+            assertTrue(i.hasNext());
 
-        // 2nd read works
-        i.next();
-        assertTrue(i.hasNext());
+            // 1st read works
+            i.next();
+            assertTrue(i.hasNext());
 
-        // 3rd read works
-        i.next();
-        assertTrue(i.hasNext());
+            // 2nd read works
+            i.next();
+            assertTrue(i.hasNext());
 
-        // 4th read blows up as it loops back to 0
-        assertThrows(RuntimeException.class, i::next, "Loop should have been detected but wasn't!");
-        assertTrue(i.hasNext());
+            // 3rd read works
+            i.next();
+            assertTrue(i.hasNext());
 
-        fs.close();
+            // 4th read blows up as it loops back to 0
+            assertThrows(RuntimeException.class, i::next, "Loop should have been detected but wasn't!");
+            assertTrue(i.hasNext());
+        }
     }
 
     /**
@@ -281,51 +285,50 @@ final class TestPOIFSStream {
      */
     @Test
     void testReadMiniStreams() throws Exception {
-        POIFSFileSystem fs = new POIFSFileSystem(_inst.openResourceAsStream("BlockSize512.zvi"));
-        POIFSMiniStore ministore = fs.getMiniStore();
-
-        // 178 -> 179 -> 180 -> end
-        POIFSStream stream = new POIFSStream(ministore, 178);
-        Iterator<ByteBuffer> i = stream.getBlockIterator();
-        assertTrue(i.hasNext());
-        ByteBuffer b178 = i.next();
-        assertTrue(i.hasNext());
-        ByteBuffer b179 = i.next();
-        assertTrue(i.hasNext());
-        ByteBuffer b180 = i.next();
-        assertFalse(i.hasNext());
-
-        // Check the contents of the 1st block
-        assertEquals((byte) 0xfe, b178.get());
-        assertEquals((byte) 0xff, b178.get());
-        assertEquals((byte) 0x00, b178.get());
-        assertEquals((byte) 0x00, b178.get());
-        assertEquals((byte) 0x05, b178.get());
-        assertEquals((byte) 0x01, b178.get());
-        assertEquals((byte) 0x02, b178.get());
-        assertEquals((byte) 0x00, b178.get());
-
-        // And the 2nd
-        assertEquals((byte) 0x6c, b179.get());
-        assertEquals((byte) 0x00, b179.get());
-        assertEquals((byte) 0x00, b179.get());
-        assertEquals((byte) 0x00, b179.get());
-        assertEquals((byte) 0x28, b179.get());
-        assertEquals((byte) 0x00, b179.get());
-        assertEquals((byte) 0x00, b179.get());
-        assertEquals((byte) 0x00, b179.get());
-
-        // And the 3rd
-        assertEquals((byte) 0x30, b180.get());
-        assertEquals((byte) 0x00, b180.get());
-        assertEquals((byte) 0x00, b180.get());
-        assertEquals((byte) 0x00, b180.get());
-        assertEquals((byte) 0x00, b180.get());
-        assertEquals((byte) 0x00, b180.get());
-        assertEquals((byte) 0x00, b180.get());
-        assertEquals((byte) 0x80, b180.get());
-
-        fs.close();
+        try (POIFSFileSystem fs = new POIFSFileSystem(_inst.openResourceAsStream("BlockSize512.zvi"))) {
+            POIFSMiniStore ministore = fs.getMiniStore();
+
+            // 178 -> 179 -> 180 -> end
+            POIFSStream stream = new POIFSStream(ministore, 178);
+            Iterator<ByteBuffer> i = stream.getBlockIterator();
+            assertTrue(i.hasNext());
+            ByteBuffer b178 = i.next();
+            assertTrue(i.hasNext());
+            ByteBuffer b179 = i.next();
+            assertTrue(i.hasNext());
+            ByteBuffer b180 = i.next();
+            assertFalse(i.hasNext());
+
+            // Check the contents of the 1st block
+            assertEquals((byte) 0xfe, b178.get());
+            assertEquals((byte) 0xff, b178.get());
+            assertEquals((byte) 0x00, b178.get());
+            assertEquals((byte) 0x00, b178.get());
+            assertEquals((byte) 0x05, b178.get());
+            assertEquals((byte) 0x01, b178.get());
+            assertEquals((byte) 0x02, b178.get());
+            assertEquals((byte) 0x00, b178.get());
+
+            // And the 2nd
+            assertEquals((byte) 0x6c, b179.get());
+            assertEquals((byte) 0x00, b179.get());
+            assertEquals((byte) 0x00, b179.get());
+            assertEquals((byte) 0x00, b179.get());
+            assertEquals((byte) 0x28, b179.get());
+            assertEquals((byte) 0x00, b179.get());
+            assertEquals((byte) 0x00, b179.get());
+            assertEquals((byte) 0x00, b179.get());
+
+            // And the 3rd
+            assertEquals((byte) 0x30, b180.get());
+            assertEquals((byte) 0x00, b180.get());
+            assertEquals((byte) 0x00, b180.get());
+            assertEquals((byte) 0x00, b180.get());
+            assertEquals((byte) 0x00, b180.get());
+            assertEquals((byte) 0x00, b180.get());
+            assertEquals((byte) 0x00, b180.get());
+            assertEquals((byte) 0x80, b180.get());
+        }
     }
 
     /**
@@ -333,32 +336,31 @@ final class TestPOIFSStream {
      */
     @Test
     void testReplaceStream() throws Exception {
-        POIFSFileSystem fs = new POIFSFileSystem(_inst.openResourceAsStream("BlockSize512.zvi"));
+        try (POIFSFileSystem fs = new POIFSFileSystem(_inst.openResourceAsStream("BlockSize512.zvi"))) {
 
-        byte[] data = new byte[512];
-        for (int i = 0; i < data.length; i++) {
-            data[i] = (byte) (i % 256);
-        }
+            byte[] data = new byte[512];
+            for (int i = 0; i < data.length; i++) {
+                data[i] = (byte) (i % 256);
+            }
 
-        // 98 is actually the last block in a two block stream...
-        POIFSStream stream = new POIFSStream(fs, 98);
-        stream.updateContents(data);
-
-        // Check the reading of blocks
-        Iterator<ByteBuffer> it = stream.getBlockIterator();
-        assertTrue(it.hasNext());
-        ByteBuffer b = it.next();
-        assertFalse(it.hasNext());
-
-        // Now check the contents
-        data = new byte[512];
-        b.get(data);
-        for (int i = 0; i < data.length; i++) {
-            byte exp = (byte) (i % 256);
-            assertEquals(exp, data[i]);
-        }
+            // 98 is actually the last block in a two block stream...
+            POIFSStream stream = new POIFSStream(fs, 98);
+            stream.updateContents(data);
 
-        fs.close();
+            // Check the reading of blocks
+            Iterator<ByteBuffer> it = stream.getBlockIterator();
+            assertTrue(it.hasNext());
+            ByteBuffer b = it.next();
+            assertFalse(it.hasNext());
+
+            // Now check the contents
+            data = new byte[512];
+            b.get(data);
+            for (int i = 0; i < data.length; i++) {
+                byte exp = (byte) (i % 256);
+                assertEquals(exp, data[i]);
+            }
+        }
     }
 
     /**
@@ -455,92 +457,91 @@ final class TestPOIFSStream {
      */
     @Test
     void testWriteNewStream() throws Exception {
-        POIFSFileSystem fs = new POIFSFileSystem(_inst.openResourceAsStream("BlockSize512.zvi"));
+        try (POIFSFileSystem fs = new POIFSFileSystem(_inst.openResourceAsStream("BlockSize512.zvi"))) {
 
-        // 100 is our first free one
-        assertEquals(POIFSConstants.FAT_SECTOR_BLOCK, fs.getNextBlock(99));
-        assertEquals(POIFSConstants.UNUSED_BLOCK, fs.getNextBlock(100));
-        assertEquals(POIFSConstants.UNUSED_BLOCK, fs.getNextBlock(101));
-        assertEquals(POIFSConstants.UNUSED_BLOCK, fs.getNextBlock(102));
-        assertEquals(POIFSConstants.UNUSED_BLOCK, fs.getNextBlock(103));
-        assertEquals(POIFSConstants.UNUSED_BLOCK, fs.getNextBlock(104));
+            // 100 is our first free one
+            assertEquals(POIFSConstants.FAT_SECTOR_BLOCK, fs.getNextBlock(99));
+            assertEquals(POIFSConstants.UNUSED_BLOCK, fs.getNextBlock(100));
+            assertEquals(POIFSConstants.UNUSED_BLOCK, fs.getNextBlock(101));
+            assertEquals(POIFSConstants.UNUSED_BLOCK, fs.getNextBlock(102));
+            assertEquals(POIFSConstants.UNUSED_BLOCK, fs.getNextBlock(103));
+            assertEquals(POIFSConstants.UNUSED_BLOCK, fs.getNextBlock(104));
 
 
-        // Add a single block one
-        byte[] data = new byte[512];
-        for (int i = 0; i < data.length; i++) {
-            data[i] = (byte) (i % 256);
-        }
+            // Add a single block one
+            byte[] data = new byte[512];
+            for (int i = 0; i < data.length; i++) {
+                data[i] = (byte) (i % 256);
+            }
 
-        POIFSStream stream = new POIFSStream(fs);
-        stream.updateContents(data);
+            POIFSStream stream = new POIFSStream(fs);
+            stream.updateContents(data);
 
-        // Check it was allocated properly
-        assertEquals(POIFSConstants.FAT_SECTOR_BLOCK, fs.getNextBlock(99));
-        assertEquals(POIFSConstants.END_OF_CHAIN, fs.getNextBlock(100));
-        assertEquals(POIFSConstants.UNUSED_BLOCK, fs.getNextBlock(101));
-        assertEquals(POIFSConstants.UNUSED_BLOCK, fs.getNextBlock(102));
-        assertEquals(POIFSConstants.UNUSED_BLOCK, fs.getNextBlock(103));
-        assertEquals(POIFSConstants.UNUSED_BLOCK, fs.getNextBlock(104));
+            // Check it was allocated properly
+            assertEquals(POIFSConstants.FAT_SECTOR_BLOCK, fs.getNextBlock(99));
+            assertEquals(POIFSConstants.END_OF_CHAIN, fs.getNextBlock(100));
+            assertEquals(POIFSConstants.UNUSED_BLOCK, fs.getNextBlock(101));
+            assertEquals(POIFSConstants.UNUSED_BLOCK, fs.getNextBlock(102));
+            assertEquals(POIFSConstants.UNUSED_BLOCK, fs.getNextBlock(103));
+            assertEquals(POIFSConstants.UNUSED_BLOCK, fs.getNextBlock(104));
 
-        // And check the contents
-        Iterator<ByteBuffer> it = stream.getBlockIterator();
-        int count = 0;
-        while (it.hasNext()) {
-            ByteBuffer b = it.next();
-            data = new byte[512];
-            b.get(data);
+            // And check the contents
+            Iterator<ByteBuffer> it = stream.getBlockIterator();
+            int count = 0;
+            while (it.hasNext()) {
+                ByteBuffer b = it.next();
+                data = new byte[512];
+                b.get(data);
+                for (int i = 0; i < data.length; i++) {
+                    byte exp = (byte) (i % 256);
+                    assertEquals(exp, data[i]);
+                }
+                count++;
+            }
+            assertEquals(1, count);
+
+
+            // And a multi block one
+            data = new byte[512 * 3];
             for (int i = 0; i < data.length; i++) {
-                byte exp = (byte) (i % 256);
-                assertEquals(exp, data[i]);
+                data[i] = (byte) (i % 256);
             }
-            count++;
-        }
-        assertEquals(1, count);
 
+            stream = new POIFSStream(fs);
+            stream.updateContents(data);
 
-        // And a multi block one
-        data = new byte[512 * 3];
-        for (int i = 0; i < data.length; i++) {
-            data[i] = (byte) (i % 256);
-        }
+            // Check it was allocated properly
+            assertEquals(POIFSConstants.FAT_SECTOR_BLOCK, fs.getNextBlock(99));
+            assertEquals(POIFSConstants.END_OF_CHAIN, fs.getNextBlock(100));
+            assertEquals(102, fs.getNextBlock(101));
+            assertEquals(103, fs.getNextBlock(102));
+            assertEquals(POIFSConstants.END_OF_CHAIN, fs.getNextBlock(103));
+            assertEquals(POIFSConstants.UNUSED_BLOCK, fs.getNextBlock(104));
 
-        stream = new POIFSStream(fs);
-        stream.updateContents(data);
-
-        // Check it was allocated properly
-        assertEquals(POIFSConstants.FAT_SECTOR_BLOCK, fs.getNextBlock(99));
-        assertEquals(POIFSConstants.END_OF_CHAIN, fs.getNextBlock(100));
-        assertEquals(102, fs.getNextBlock(101));
-        assertEquals(103, fs.getNextBlock(102));
-        assertEquals(POIFSConstants.END_OF_CHAIN, fs.getNextBlock(103));
-        assertEquals(POIFSConstants.UNUSED_BLOCK, fs.getNextBlock(104));
-
-        // And check the contents
-        it = stream.getBlockIterator();
-        count = 0;
-        while (it.hasNext()) {
-            ByteBuffer b = it.next();
-            data = new byte[512];
-            b.get(data);
-            for (int i = 0; i < data.length; i++) {
-                byte exp = (byte) (i % 256);
-                assertEquals(exp, data[i]);
+            // And check the contents
+            it = stream.getBlockIterator();
+            count = 0;
+            while (it.hasNext()) {
+                ByteBuffer b = it.next();
+                data = new byte[512];
+                b.get(data);
+                for (int i = 0; i < data.length; i++) {
+                    byte exp = (byte) (i % 256);
+                    assertEquals(exp, data[i]);
+                }
+                count++;
             }
-            count++;
+            assertEquals(3, count);
+
+            // Free it
+            stream.free();
+            assertEquals(POIFSConstants.FAT_SECTOR_BLOCK, fs.getNextBlock(99));
+            assertEquals(POIFSConstants.END_OF_CHAIN, fs.getNextBlock(100));
+            assertEquals(POIFSConstants.UNUSED_BLOCK, fs.getNextBlock(101));
+            assertEquals(POIFSConstants.UNUSED_BLOCK, fs.getNextBlock(102));
+            assertEquals(POIFSConstants.UNUSED_BLOCK, fs.getNextBlock(103));
+            assertEquals(POIFSConstants.UNUSED_BLOCK, fs.getNextBlock(104));
         }
-        assertEquals(3, count);
-
-        // Free it
-        stream.free();
-        assertEquals(POIFSConstants.FAT_SECTOR_BLOCK, fs.getNextBlock(99));
-        assertEquals(POIFSConstants.END_OF_CHAIN, fs.getNextBlock(100));
-        assertEquals(POIFSConstants.UNUSED_BLOCK, fs.getNextBlock(101));
-        assertEquals(POIFSConstants.UNUSED_BLOCK, fs.getNextBlock(102));
-        assertEquals(POIFSConstants.UNUSED_BLOCK, fs.getNextBlock(103));
-        assertEquals(POIFSConstants.UNUSED_BLOCK, fs.getNextBlock(104));
-
-        fs.close();
     }
 
     /**
@@ -550,40 +551,39 @@ final class TestPOIFSStream {
      */
     @Test
     void testWriteNewStreamExtraFATs() throws Exception {
-        POIFSFileSystem fs = new POIFSFileSystem(_inst.openResourceAsStream("BlockSize512.zvi"));
-
-        // Allocate almost all the blocks
-        assertEquals(POIFSConstants.FAT_SECTOR_BLOCK, fs.getNextBlock(99));
-        assertEquals(POIFSConstants.UNUSED_BLOCK, fs.getNextBlock(100));
-        assertEquals(POIFSConstants.UNUSED_BLOCK, fs.getNextBlock(127));
-        for (int i = 100; i < 127; i++) {
-            fs.setNextBlock(i, POIFSConstants.END_OF_CHAIN);
-        }
-        assertEquals(POIFSConstants.UNUSED_BLOCK, fs.getNextBlock(127));
-        assertTrue(fs.getBATBlockAndIndex(0).getBlock().hasFreeSectors());
+        try (POIFSFileSystem fs = new POIFSFileSystem(_inst.openResourceAsStream("BlockSize512.zvi"))) {
 
+            // Allocate almost all the blocks
+            assertEquals(POIFSConstants.FAT_SECTOR_BLOCK, fs.getNextBlock(99));
+            assertEquals(POIFSConstants.UNUSED_BLOCK, fs.getNextBlock(100));
+            assertEquals(POIFSConstants.UNUSED_BLOCK, fs.getNextBlock(127));
+            for (int i = 100; i < 127; i++) {
+                fs.setNextBlock(i, POIFSConstants.END_OF_CHAIN);
+            }
+            assertEquals(POIFSConstants.UNUSED_BLOCK, fs.getNextBlock(127));
+            assertTrue(fs.getBATBlockAndIndex(0).getBlock().hasFreeSectors());
 
-        // Write a 3 block stream
-        byte[] data = new byte[512 * 3];
-        for (int i = 0; i < data.length; i++) {
-            data[i] = (byte) (i % 256);
+
+            // Write a 3 block stream
+            byte[] data = new byte[512 * 3];
+            for (int i = 0; i < data.length; i++) {
+                data[i] = (byte) (i % 256);
+            }
+            POIFSStream stream = new POIFSStream(fs);
+            stream.updateContents(data);
+
+            // Check we got another BAT
+            assertFalse(fs.getBATBlockAndIndex(0).getBlock().hasFreeSectors());
+            assertTrue(fs.getBATBlockAndIndex(128).getBlock().hasFreeSectors());
+
+            // the BAT will be in the first spot of the new block
+            assertEquals(POIFSConstants.END_OF_CHAIN, fs.getNextBlock(126));
+            assertEquals(129, fs.getNextBlock(127));
+            assertEquals(POIFSConstants.FAT_SECTOR_BLOCK, fs.getNextBlock(128));
+            assertEquals(130, fs.getNextBlock(129));
+            assertEquals(POIFSConstants.END_OF_CHAIN, fs.getNextBlock(130));
+            assertEquals(POIFSConstants.UNUSED_BLOCK, fs.getNextBlock(131));
         }
-        POIFSStream stream = new POIFSStream(fs);
-        stream.updateContents(data);
-
-        // Check we got another BAT
-        assertFalse(fs.getBATBlockAndIndex(0).getBlock().hasFreeSectors());
-        assertTrue(fs.getBATBlockAndIndex(128).getBlock().hasFreeSectors());
-
-        // the BAT will be in the first spot of the new block
-        assertEquals(POIFSConstants.END_OF_CHAIN, fs.getNextBlock(126));
-        assertEquals(129, fs.getNextBlock(127));
-        assertEquals(POIFSConstants.FAT_SECTOR_BLOCK, fs.getNextBlock(128));
-        assertEquals(130, fs.getNextBlock(129));
-        assertEquals(POIFSConstants.END_OF_CHAIN, fs.getNextBlock(130));
-        assertEquals(POIFSConstants.UNUSED_BLOCK, fs.getNextBlock(131));
-
-        fs.close();
     }
 
     /**
@@ -592,54 +592,53 @@ final class TestPOIFSStream {
      */
     @Test
     void testWriteStream4096() throws Exception {
-        POIFSFileSystem fs = new POIFSFileSystem(_inst.openResourceAsStream("BlockSize4096.zvi"));
+        try (POIFSFileSystem fs = new POIFSFileSystem(_inst.openResourceAsStream("BlockSize4096.zvi"))) {
 
-        // 0 -> 1 -> 2 -> end
-        assertEquals(1, fs.getNextBlock(0));
-        assertEquals(2, fs.getNextBlock(1));
-        assertEquals(POIFSConstants.END_OF_CHAIN, fs.getNextBlock(2));
-        assertEquals(4, fs.getNextBlock(3));
+            // 0 -> 1 -> 2 -> end
+            assertEquals(1, fs.getNextBlock(0));
+            assertEquals(2, fs.getNextBlock(1));
+            assertEquals(POIFSConstants.END_OF_CHAIN, fs.getNextBlock(2));
+            assertEquals(4, fs.getNextBlock(3));
 
-        // First free one is at 15
-        assertEquals(POIFSConstants.FAT_SECTOR_BLOCK, fs.getNextBlock(14));
-        assertEquals(POIFSConstants.UNUSED_BLOCK, fs.getNextBlock(15));
+            // First free one is at 15
+            assertEquals(POIFSConstants.FAT_SECTOR_BLOCK, fs.getNextBlock(14));
+            assertEquals(POIFSConstants.UNUSED_BLOCK, fs.getNextBlock(15));
 
 
-        // Write a 5 block file
-        byte[] data = new byte[4096 * 5];
-        for (int i = 0; i < data.length; i++) {
-            data[i] = (byte) (i % 256);
-        }
-        POIFSStream stream = new POIFSStream(fs, 0);
-        stream.updateContents(data);
-
-
-        // Check it
-        assertEquals(1, fs.getNextBlock(0));
-        assertEquals(2, fs.getNextBlock(1));
-        assertEquals(15, fs.getNextBlock(2)); // Jumps
-        assertEquals(4, fs.getNextBlock(3));  // Next stream
-        assertEquals(POIFSConstants.FAT_SECTOR_BLOCK, fs.getNextBlock(14));
-        assertEquals(16, fs.getNextBlock(15)); // Continues
-        assertEquals(POIFSConstants.END_OF_CHAIN, fs.getNextBlock(16)); // Ends
-        assertEquals(POIFSConstants.UNUSED_BLOCK, fs.getNextBlock(17)); // Free
-
-        // Check the contents too
-        Iterator<ByteBuffer> it = stream.getBlockIterator();
-        int count = 0;
-        while (it.hasNext()) {
-            ByteBuffer b = it.next();
-            data = new byte[512];
-            b.get(data);
+            // Write a 5 block file
+            byte[] data = new byte[4096 * 5];
             for (int i = 0; i < data.length; i++) {
-                byte exp = (byte) (i % 256);
-                assertEquals(exp, data[i]);
+                data[i] = (byte) (i % 256);
             }
-            count++;
-        }
-        assertEquals(5, count);
+            POIFSStream stream = new POIFSStream(fs, 0);
+            stream.updateContents(data);
+
 
-        fs.close();
+            // Check it
+            assertEquals(1, fs.getNextBlock(0));
+            assertEquals(2, fs.getNextBlock(1));
+            assertEquals(15, fs.getNextBlock(2)); // Jumps
+            assertEquals(4, fs.getNextBlock(3));  // Next stream
+            assertEquals(POIFSConstants.FAT_SECTOR_BLOCK, fs.getNextBlock(14));
+            assertEquals(16, fs.getNextBlock(15)); // Continues
+            assertEquals(POIFSConstants.END_OF_CHAIN, fs.getNextBlock(16)); // Ends
+            assertEquals(POIFSConstants.UNUSED_BLOCK, fs.getNextBlock(17)); // Free
+
+            // Check the contents too
+            Iterator<ByteBuffer> it = stream.getBlockIterator();
+            int count = 0;
+            while (it.hasNext()) {
+                ByteBuffer b = it.next();
+                data = new byte[512];
+                b.get(data);
+                for (int i = 0; i < data.length; i++) {
+                    byte exp = (byte) (i % 256);
+                    assertEquals(exp, data[i]);
+                }
+                count++;
+            }
+            assertEquals(5, count);
+        }
     }
 
     /**
@@ -933,191 +932,192 @@ final class TestPOIFSStream {
      */
     @Test
     void testWriteThenReplace() throws Exception {
-        POIFSFileSystem fs = new POIFSFileSystem();
-
-        // Starts empty, other that Properties and BAT
-        BATBlock bat = fs.getBATBlockAndIndex(0).getBlock();
-        assertEquals(POIFSConstants.END_OF_CHAIN, bat.getValueAt(0));
-        assertEquals(POIFSConstants.FAT_SECTOR_BLOCK, bat.getValueAt(1));
-        assertEquals(POIFSConstants.UNUSED_BLOCK, bat.getValueAt(2));
-
-        // Write something that uses a main stream
-        byte[] main4106 = new byte[4106];
-        main4106[0] = -10;
-        main4106[4105] = -11;
-        fs.getRoot().createDocument("Normal", new ByteArrayInputStream(main4106));
-
-        // Should have used 9 blocks
-        assertEquals(POIFSConstants.END_OF_CHAIN, bat.getValueAt(0));
-        assertEquals(POIFSConstants.FAT_SECTOR_BLOCK, bat.getValueAt(1));
-        assertEquals(3, bat.getValueAt(2));
-        assertEquals(4, bat.getValueAt(3));
-        assertEquals(5, bat.getValueAt(4));
-        assertEquals(6, bat.getValueAt(5));
-        assertEquals(7, bat.getValueAt(6));
-        assertEquals(8, bat.getValueAt(7));
-        assertEquals(9, bat.getValueAt(8));
-        assertEquals(10, bat.getValueAt(9));
-        assertEquals(POIFSConstants.END_OF_CHAIN, bat.getValueAt(10));
-        assertEquals(POIFSConstants.UNUSED_BLOCK, bat.getValueAt(11));
-
-        DocumentEntry normal = (DocumentEntry) fs.getRoot().getEntry("Normal");
-        assertEquals(4106, normal.getSize());
-        assertEquals(4106, ((DocumentNode) normal).getProperty().getSize());
-
-
-        // Replace with one still big enough for a main stream, but one block smaller
-        byte[] main4096 = new byte[4096];
-        main4096[0] = -10;
-        main4096[4095] = -11;
-
-        DocumentOutputStream nout = new DocumentOutputStream(normal);
-        nout.write(main4096);
-        nout.close();
-
-        // Will have dropped to 8
-        assertEquals(POIFSConstants.END_OF_CHAIN, bat.getValueAt(0));
-        assertEquals(POIFSConstants.FAT_SECTOR_BLOCK, bat.getValueAt(1));
-        assertEquals(3, bat.getValueAt(2));
-        assertEquals(4, bat.getValueAt(3));
-        assertEquals(5, bat.getValueAt(4));
-        assertEquals(6, bat.getValueAt(5));
-        assertEquals(7, bat.getValueAt(6));
-        assertEquals(8, bat.getValueAt(7));
-        assertEquals(9, bat.getValueAt(8));
-        assertEquals(POIFSConstants.END_OF_CHAIN, bat.getValueAt(9));
-        assertEquals(POIFSConstants.UNUSED_BLOCK, bat.getValueAt(10));
-        assertEquals(POIFSConstants.UNUSED_BLOCK, bat.getValueAt(11));
-
-        normal = (DocumentEntry) fs.getRoot().getEntry("Normal");
-        assertEquals(4096, normal.getSize());
-        assertEquals(4096, ((DocumentNode) normal).getProperty().getSize());
-
-
-        // Write and check
-        fs = writeOutAndReadBack(fs);
-        bat = fs.getBATBlockAndIndex(0).getBlock();
-
-        // No change after write
-        assertEquals(POIFSConstants.END_OF_CHAIN, bat.getValueAt(0)); // Properties
-        assertEquals(POIFSConstants.FAT_SECTOR_BLOCK, bat.getValueAt(1));
-        assertEquals(3, bat.getValueAt(2));
-        assertEquals(4, bat.getValueAt(3));
-        assertEquals(5, bat.getValueAt(4));
-        assertEquals(6, bat.getValueAt(5));
-        assertEquals(7, bat.getValueAt(6));
-        assertEquals(8, bat.getValueAt(7));
-        assertEquals(9, bat.getValueAt(8));
-        assertEquals(POIFSConstants.END_OF_CHAIN, bat.getValueAt(9)); // End of Normal
-        assertEquals(POIFSConstants.UNUSED_BLOCK, bat.getValueAt(10));
-        assertEquals(POIFSConstants.UNUSED_BLOCK, bat.getValueAt(11));
-
-        normal = (DocumentEntry) fs.getRoot().getEntry("Normal");
-        assertEquals(4096, normal.getSize());
-        assertEquals(4096, ((DocumentNode) normal).getProperty().getSize());
-
-
-        // Make longer, take 1 block at the end
-        normal = (DocumentEntry) fs.getRoot().getEntry("Normal");
-        nout = new DocumentOutputStream(normal);
-        nout.write(main4106);
-        nout.close();
-
-        assertEquals(POIFSConstants.END_OF_CHAIN, bat.getValueAt(0));
-        assertEquals(POIFSConstants.FAT_SECTOR_BLOCK, bat.getValueAt(1));
-        assertEquals(3, bat.getValueAt(2));
-        assertEquals(4, bat.getValueAt(3));
-        assertEquals(5, bat.getValueAt(4));
-        assertEquals(6, bat.getValueAt(5));
-        assertEquals(7, bat.getValueAt(6));
-        assertEquals(8, bat.getValueAt(7));
-        assertEquals(9, bat.getValueAt(8));
-        assertEquals(10, bat.getValueAt(9));
-        assertEquals(POIFSConstants.END_OF_CHAIN, bat.getValueAt(10)); // Normal
-        assertEquals(POIFSConstants.UNUSED_BLOCK, bat.getValueAt(11));
-        assertEquals(POIFSConstants.UNUSED_BLOCK, bat.getValueAt(12));
-
-        normal = (DocumentEntry) fs.getRoot().getEntry("Normal");
-        assertEquals(4106, normal.getSize());
-        assertEquals(4106, ((DocumentNode) normal).getProperty().getSize());
-
-
-        // Make it small, will trigger the SBAT stream and free lots up
-        byte[] mini = new byte[]{42, 0, 1, 2, 3, 4, 42};
-        normal = (DocumentEntry) fs.getRoot().getEntry("Normal");
-        nout = new DocumentOutputStream(normal);
-        nout.write(mini);
-        nout.close();
-
-        assertEquals(POIFSConstants.END_OF_CHAIN, bat.getValueAt(0));
-        assertEquals(POIFSConstants.FAT_SECTOR_BLOCK, bat.getValueAt(1));
-        assertEquals(POIFSConstants.END_OF_CHAIN, bat.getValueAt(2)); // SBAT
-        assertEquals(POIFSConstants.END_OF_CHAIN, bat.getValueAt(3)); // Mini Stream
-        assertEquals(POIFSConstants.UNUSED_BLOCK, bat.getValueAt(4));
-        assertEquals(POIFSConstants.UNUSED_BLOCK, bat.getValueAt(5));
-        assertEquals(POIFSConstants.UNUSED_BLOCK, bat.getValueAt(6));
-        assertEquals(POIFSConstants.UNUSED_BLOCK, bat.getValueAt(7));
-        assertEquals(POIFSConstants.UNUSED_BLOCK, bat.getValueAt(8));
-        assertEquals(POIFSConstants.UNUSED_BLOCK, bat.getValueAt(9));
-        assertEquals(POIFSConstants.UNUSED_BLOCK, bat.getValueAt(10));
-        assertEquals(POIFSConstants.UNUSED_BLOCK, bat.getValueAt(11));
-        assertEquals(POIFSConstants.UNUSED_BLOCK, bat.getValueAt(12));
-
-        normal = (DocumentEntry) fs.getRoot().getEntry("Normal");
-        assertEquals(7, normal.getSize());
-        assertEquals(7, ((DocumentNode) normal).getProperty().getSize());
-
-
-        // Finally back to big again
-        nout = new DocumentOutputStream(normal);
-        nout.write(main4096);
-        nout.close();
-
-        // Will keep the mini stream, now empty
-        assertEquals(POIFSConstants.END_OF_CHAIN, bat.getValueAt(0));
-        assertEquals(POIFSConstants.FAT_SECTOR_BLOCK, bat.getValueAt(1));
-        assertEquals(POIFSConstants.END_OF_CHAIN, bat.getValueAt(2)); // SBAT
-        assertEquals(POIFSConstants.END_OF_CHAIN, bat.getValueAt(3)); // Mini Stream
-        assertEquals(5, bat.getValueAt(4));
-        assertEquals(6, bat.getValueAt(5));
-        assertEquals(7, bat.getValueAt(6));
-        assertEquals(8, bat.getValueAt(7));
-        assertEquals(9, bat.getValueAt(8));
-        assertEquals(10, bat.getValueAt(9));
-        assertEquals(11, bat.getValueAt(10));
-        assertEquals(POIFSConstants.END_OF_CHAIN, bat.getValueAt(11));
-        assertEquals(POIFSConstants.UNUSED_BLOCK, bat.getValueAt(12));
-        assertEquals(POIFSConstants.UNUSED_BLOCK, bat.getValueAt(13));
-
-        normal = (DocumentEntry) fs.getRoot().getEntry("Normal");
-        assertEquals(4096, normal.getSize());
-        assertEquals(4096, ((DocumentNode) normal).getProperty().getSize());
-
-
-        // Save, re-load, re-check
-        fs = writeOutAndReadBack(fs);
-        bat = fs.getBATBlockAndIndex(0).getBlock();
-
-        assertEquals(POIFSConstants.END_OF_CHAIN, bat.getValueAt(0));
-        assertEquals(POIFSConstants.FAT_SECTOR_BLOCK, bat.getValueAt(1));
-        assertEquals(POIFSConstants.END_OF_CHAIN, bat.getValueAt(2)); // SBAT
-        assertEquals(POIFSConstants.END_OF_CHAIN, bat.getValueAt(3)); // Mini Stream
-        assertEquals(5, bat.getValueAt(4));
-        assertEquals(6, bat.getValueAt(5));
-        assertEquals(7, bat.getValueAt(6));
-        assertEquals(8, bat.getValueAt(7));
-        assertEquals(9, bat.getValueAt(8));
-        assertEquals(10, bat.getValueAt(9));
-        assertEquals(11, bat.getValueAt(10));
-        assertEquals(POIFSConstants.END_OF_CHAIN, bat.getValueAt(11));
-        assertEquals(POIFSConstants.UNUSED_BLOCK, bat.getValueAt(12));
-        assertEquals(POIFSConstants.UNUSED_BLOCK, bat.getValueAt(13));
-
-        normal = (DocumentEntry) fs.getRoot().getEntry("Normal");
-        assertEquals(4096, normal.getSize());
-        assertEquals(4096, ((DocumentNode) normal).getProperty().getSize());
-
-        fs.close();
+        try (POIFSFileSystem fs1 = new POIFSFileSystem()) {
+
+            // Starts empty, other that Properties and BAT
+            BATBlock bat = fs1.getBATBlockAndIndex(0).getBlock();
+            assertEquals(POIFSConstants.END_OF_CHAIN, bat.getValueAt(0));
+            assertEquals(POIFSConstants.FAT_SECTOR_BLOCK, bat.getValueAt(1));
+            assertEquals(POIFSConstants.UNUSED_BLOCK, bat.getValueAt(2));
+
+            // Write something that uses a main stream
+            byte[] main4106 = new byte[4106];
+            main4106[0] = -10;
+            main4106[4105] = -11;
+            fs1.getRoot().createDocument("Normal", new ByteArrayInputStream(main4106));
+
+            // Should have used 9 blocks
+            assertEquals(POIFSConstants.END_OF_CHAIN, bat.getValueAt(0));
+            assertEquals(POIFSConstants.FAT_SECTOR_BLOCK, bat.getValueAt(1));
+            assertEquals(3, bat.getValueAt(2));
+            assertEquals(4, bat.getValueAt(3));
+            assertEquals(5, bat.getValueAt(4));
+            assertEquals(6, bat.getValueAt(5));
+            assertEquals(7, bat.getValueAt(6));
+            assertEquals(8, bat.getValueAt(7));
+            assertEquals(9, bat.getValueAt(8));
+            assertEquals(10, bat.getValueAt(9));
+            assertEquals(POIFSConstants.END_OF_CHAIN, bat.getValueAt(10));
+            assertEquals(POIFSConstants.UNUSED_BLOCK, bat.getValueAt(11));
+
+            DocumentEntry normal = (DocumentEntry) fs1.getRoot().getEntry("Normal");
+            assertEquals(4106, normal.getSize());
+            assertEquals(4106, ((DocumentNode) normal).getProperty().getSize());
+
+
+            // Replace with one still big enough for a main stream, but one block smaller
+            byte[] main4096 = new byte[4096];
+            main4096[0] = -10;
+            main4096[4095] = -11;
+
+            try (DocumentOutputStream nout = new DocumentOutputStream(normal)) {
+                nout.write(main4096);
+            }
+
+            // Will have dropped to 8
+            assertEquals(POIFSConstants.END_OF_CHAIN, bat.getValueAt(0));
+            assertEquals(POIFSConstants.FAT_SECTOR_BLOCK, bat.getValueAt(1));
+            assertEquals(3, bat.getValueAt(2));
+            assertEquals(4, bat.getValueAt(3));
+            assertEquals(5, bat.getValueAt(4));
+            assertEquals(6, bat.getValueAt(5));
+            assertEquals(7, bat.getValueAt(6));
+            assertEquals(8, bat.getValueAt(7));
+            assertEquals(9, bat.getValueAt(8));
+            assertEquals(POIFSConstants.END_OF_CHAIN, bat.getValueAt(9));
+            assertEquals(POIFSConstants.UNUSED_BLOCK, bat.getValueAt(10));
+            assertEquals(POIFSConstants.UNUSED_BLOCK, bat.getValueAt(11));
+
+            normal = (DocumentEntry) fs1.getRoot().getEntry("Normal");
+            assertEquals(4096, normal.getSize());
+            assertEquals(4096, ((DocumentNode) normal).getProperty().getSize());
+
+
+            // Write and check
+            try (POIFSFileSystem fs2 = writeOutAndReadBack(fs1)) {
+                bat = fs2.getBATBlockAndIndex(0).getBlock();
+
+                // No change after write
+                assertEquals(POIFSConstants.END_OF_CHAIN, bat.getValueAt(0)); // Properties
+                assertEquals(POIFSConstants.FAT_SECTOR_BLOCK, bat.getValueAt(1));
+                assertEquals(3, bat.getValueAt(2));
+                assertEquals(4, bat.getValueAt(3));
+                assertEquals(5, bat.getValueAt(4));
+                assertEquals(6, bat.getValueAt(5));
+                assertEquals(7, bat.getValueAt(6));
+                assertEquals(8, bat.getValueAt(7));
+                assertEquals(9, bat.getValueAt(8));
+                assertEquals(POIFSConstants.END_OF_CHAIN, bat.getValueAt(9)); // End of Normal
+                assertEquals(POIFSConstants.UNUSED_BLOCK, bat.getValueAt(10));
+                assertEquals(POIFSConstants.UNUSED_BLOCK, bat.getValueAt(11));
+
+                normal = (DocumentEntry) fs2.getRoot().getEntry("Normal");
+                assertEquals(4096, normal.getSize());
+                assertEquals(4096, ((DocumentNode) normal).getProperty().getSize());
+
+
+                // Make longer, take 1 block at the end
+                normal = (DocumentEntry) fs2.getRoot().getEntry("Normal");
+                try (DocumentOutputStream nout = new DocumentOutputStream(normal)) {
+                    nout.write(main4106);
+                }
+
+                assertEquals(POIFSConstants.END_OF_CHAIN, bat.getValueAt(0));
+                assertEquals(POIFSConstants.FAT_SECTOR_BLOCK, bat.getValueAt(1));
+                assertEquals(3, bat.getValueAt(2));
+                assertEquals(4, bat.getValueAt(3));
+                assertEquals(5, bat.getValueAt(4));
+                assertEquals(6, bat.getValueAt(5));
+                assertEquals(7, bat.getValueAt(6));
+                assertEquals(8, bat.getValueAt(7));
+                assertEquals(9, bat.getValueAt(8));
+                assertEquals(10, bat.getValueAt(9));
+                assertEquals(POIFSConstants.END_OF_CHAIN, bat.getValueAt(10)); // Normal
+                assertEquals(POIFSConstants.UNUSED_BLOCK, bat.getValueAt(11));
+                assertEquals(POIFSConstants.UNUSED_BLOCK, bat.getValueAt(12));
+
+                normal = (DocumentEntry) fs2.getRoot().getEntry("Normal");
+                assertEquals(4106, normal.getSize());
+                assertEquals(4106, ((DocumentNode) normal).getProperty().getSize());
+
+
+                // Make it small, will trigger the SBAT stream and free lots up
+                byte[] mini = new byte[]{42, 0, 1, 2, 3, 4, 42};
+                normal = (DocumentEntry) fs2.getRoot().getEntry("Normal");
+                try (DocumentOutputStream nout = new DocumentOutputStream(normal)) {
+                    nout.write(mini);
+                }
+
+                assertEquals(POIFSConstants.END_OF_CHAIN, bat.getValueAt(0));
+                assertEquals(POIFSConstants.FAT_SECTOR_BLOCK, bat.getValueAt(1));
+                assertEquals(POIFSConstants.END_OF_CHAIN, bat.getValueAt(2)); // SBAT
+                assertEquals(POIFSConstants.END_OF_CHAIN, bat.getValueAt(3)); // Mini Stream
+                assertEquals(POIFSConstants.UNUSED_BLOCK, bat.getValueAt(4));
+                assertEquals(POIFSConstants.UNUSED_BLOCK, bat.getValueAt(5));
+                assertEquals(POIFSConstants.UNUSED_BLOCK, bat.getValueAt(6));
+                assertEquals(POIFSConstants.UNUSED_BLOCK, bat.getValueAt(7));
+                assertEquals(POIFSConstants.UNUSED_BLOCK, bat.getValueAt(8));
+                assertEquals(POIFSConstants.UNUSED_BLOCK, bat.getValueAt(9));
+                assertEquals(POIFSConstants.UNUSED_BLOCK, bat.getValueAt(10));
+                assertEquals(POIFSConstants.UNUSED_BLOCK, bat.getValueAt(11));
+                assertEquals(POIFSConstants.UNUSED_BLOCK, bat.getValueAt(12));
+
+                normal = (DocumentEntry) fs2.getRoot().getEntry("Normal");
+                assertEquals(7, normal.getSize());
+                assertEquals(7, ((DocumentNode) normal).getProperty().getSize());
+
+
+                // Finally back to big again
+                try (DocumentOutputStream nout = new DocumentOutputStream(normal)) {
+                    nout.write(main4096);
+                }
+
+                // Will keep the mini stream, now empty
+                assertEquals(POIFSConstants.END_OF_CHAIN, bat.getValueAt(0));
+                assertEquals(POIFSConstants.FAT_SECTOR_BLOCK, bat.getValueAt(1));
+                assertEquals(POIFSConstants.END_OF_CHAIN, bat.getValueAt(2)); // SBAT
+                assertEquals(POIFSConstants.END_OF_CHAIN, bat.getValueAt(3)); // Mini Stream
+                assertEquals(5, bat.getValueAt(4));
+                assertEquals(6, bat.getValueAt(5));
+                assertEquals(7, bat.getValueAt(6));
+                assertEquals(8, bat.getValueAt(7));
+                assertEquals(9, bat.getValueAt(8));
+                assertEquals(10, bat.getValueAt(9));
+                assertEquals(11, bat.getValueAt(10));
+                assertEquals(POIFSConstants.END_OF_CHAIN, bat.getValueAt(11));
+                assertEquals(POIFSConstants.UNUSED_BLOCK, bat.getValueAt(12));
+                assertEquals(POIFSConstants.UNUSED_BLOCK, bat.getValueAt(13));
+
+                normal = (DocumentEntry) fs2.getRoot().getEntry("Normal");
+                assertEquals(4096, normal.getSize());
+                assertEquals(4096, ((DocumentNode) normal).getProperty().getSize());
+
+
+                // Save, re-load, re-check
+                try (POIFSFileSystem fs3 = writeOutAndReadBack(fs2)) {
+                    bat = fs3.getBATBlockAndIndex(0).getBlock();
+
+                    assertEquals(POIFSConstants.END_OF_CHAIN, bat.getValueAt(0));
+                    assertEquals(POIFSConstants.FAT_SECTOR_BLOCK, bat.getValueAt(1));
+                    assertEquals(POIFSConstants.END_OF_CHAIN, bat.getValueAt(2)); // SBAT
+                    assertEquals(POIFSConstants.END_OF_CHAIN, bat.getValueAt(3)); // Mini Stream
+                    assertEquals(5, bat.getValueAt(4));
+                    assertEquals(6, bat.getValueAt(5));
+                    assertEquals(7, bat.getValueAt(6));
+                    assertEquals(8, bat.getValueAt(7));
+                    assertEquals(9, bat.getValueAt(8));
+                    assertEquals(10, bat.getValueAt(9));
+                    assertEquals(11, bat.getValueAt(10));
+                    assertEquals(POIFSConstants.END_OF_CHAIN, bat.getValueAt(11));
+                    assertEquals(POIFSConstants.UNUSED_BLOCK, bat.getValueAt(12));
+                    assertEquals(POIFSConstants.UNUSED_BLOCK, bat.getValueAt(13));
+
+                    normal = (DocumentEntry) fs3.getRoot().getEntry("Normal");
+                    assertEquals(4096, normal.getSize());
+                    assertEquals(4096, ((DocumentNode) normal).getProperty().getSize());
+                }
+            }
+        }
     }
 
 
@@ -1125,14 +1125,43 @@ final class TestPOIFSStream {
      * Returns test files with 512 byte and 4k block sizes, loaded
      * both from InputStreams and Files
      */
-    private POIFSFileSystem[] get512and4kFileAndInput() throws IOException {
-        POIFSFileSystem fsA = new POIFSFileSystem(_inst.getFile("BlockSize512.zvi"));
-        POIFSFileSystem fsB = new POIFSFileSystem(_inst.openResourceAsStream("BlockSize512.zvi"));
-        POIFSFileSystem fsC = new POIFSFileSystem(_inst.getFile("BlockSize4096.zvi"));
-        POIFSFileSystem fsD = new POIFSFileSystem(_inst.openResourceAsStream("BlockSize4096.zvi"));
-        return new POIFSFileSystem[]{fsA, fsB, fsC, fsD};
+    public static Collection<Arguments> get512and4kFileAndInput() {
+        return CollectionUtils.union(get512FileAndInput(), get4kFileAndInput());
+    }
+
+    public static List<Arguments> get512FileAndInput() {
+        return Arrays.asList(
+            Arguments.of("BlockSize512.zvi", (Function<String,POIFSFileSystem>)TestPOIFSStream::openAsFile),
+            Arguments.of("BlockSize512.zvi", (Function<String,POIFSFileSystem>)TestPOIFSStream::openAsStream)
+        );
     }
 
+    public static List<Arguments> get4kFileAndInput() {
+        return Arrays.asList(
+            Arguments.of("BlockSize4096.zvi", (Function<String,POIFSFileSystem>)TestPOIFSStream::openAsFile),
+            Arguments.of("BlockSize4096.zvi", (Function<String,POIFSFileSystem>)TestPOIFSStream::openAsStream)
+        );
+    }
+
+    private static POIFSFileSystem openAsFile(String fileName) {
+        try {
+            return new POIFSFileSystem(_inst.getFile(fileName));
+        } catch (IOException e) {
+            fail(e);
+            return null;
+        }
+    }
+
+    private static POIFSFileSystem openAsStream(String fileName) {
+        try {
+            return new POIFSFileSystem(_inst.openResourceAsStream(fileName));
+        } catch (IOException e) {
+            fail(e);
+            return null;
+        }
+    }
+
+
     private static void assertBATCount(POIFSFileSystem fs, int expectedBAT, int expectedXBAT) throws IOException {
         int foundBAT = 0;
         int foundXBAT = 0;
@@ -1161,16 +1190,9 @@ final class TestPOIFSStream {
     }
 
     private static HeaderBlock writeOutAndReadHeader(POIFSFileSystem fs) throws IOException {
-        ByteArrayOutputStream baos = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
         fs.writeFilesystem(baos);
-
-        return new HeaderBlock(new ByteArrayInputStream(baos.toByteArray()));
-    }
-
-    private static POIFSFileSystem writeOutAndReadBack(POIFSFileSystem original) throws IOException {
-        ByteArrayOutputStream baos = new ByteArrayOutputStream();
-        original.writeFilesystem(baos);
-        return new POIFSFileSystem(new ByteArrayInputStream(baos.toByteArray()));
+        return new HeaderBlock(baos.toInputStream());
     }
 
     private static POIFSFileSystem writeOutFileAndReadBack(POIFSFileSystem original) throws IOException {
@@ -1181,37 +1203,29 @@ final class TestPOIFSStream {
         return new POIFSFileSystem(file, false);
     }
 
-    @Test
-    void basicOpen() throws IOException {
-        POIFSFileSystem fsA, fsB;
-
+    @ParameterizedTest()
+    @MethodSource("get512FileAndInput")
+    void basicOpen512(String file, Function<String,POIFSFileSystem> opener) throws IOException {
         // With a simple 512 block file
-        fsA = new POIFSFileSystem(_inst.getFile("BlockSize512.zvi"));
-        fsB = new POIFSFileSystem(_inst.openResourceAsStream("BlockSize512.zvi"));
-        for (POIFSFileSystem fs : new POIFSFileSystem[]{fsA, fsB}) {
+        try (POIFSFileSystem fs = opener.apply(file)) {
             assertEquals(512, fs.getBigBlockSize());
         }
-        fsA.close();
-        fsB.close();
+    }
 
+    @ParameterizedTest()
+    @MethodSource("get4kFileAndInput")
+    void basicOpen4k(String file, Function<String,POIFSFileSystem> opener) throws IOException {
         // Now with a simple 4096 block file
-        fsA = new POIFSFileSystem(_inst.getFile("BlockSize4096.zvi"));
-        fsB = new POIFSFileSystem(_inst.openResourceAsStream("BlockSize4096.zvi"));
-        for (POIFSFileSystem fs : new POIFSFileSystem[]{fsA, fsB}) {
+        try (POIFSFileSystem fs = opener.apply(file)) {
             assertEquals(4096, fs.getBigBlockSize());
         }
-        fsA.close();
-        fsB.close();
     }
 
-    @Test
-    void propertiesAndFatOnRead() throws IOException {
-        POIFSFileSystem fsA, fsB;
-
+    @ParameterizedTest()
+    @MethodSource("get512FileAndInput")
+    void propertiesAndFatOnRead512(String file, Function<String,POIFSFileSystem> opener) throws IOException {
         // With a simple 512 block file
-        fsA = new POIFSFileSystem(_inst.getFile("BlockSize512.zvi"));
-        fsB = new POIFSFileSystem(_inst.openResourceAsStream("BlockSize512.zvi"));
-        for (POIFSFileSystem fs : new POIFSFileSystem[]{fsA, fsB}) {
+        try (POIFSFileSystem fs = opener.apply(file)) {
             // Check the FAT was properly processed:
             // Verify we only got one block
             fs.getBATBlockAndIndex(0);
@@ -1266,14 +1280,14 @@ final class TestPOIFSStream {
                 assertEquals(i + 1, ministore.getNextBlock(i));
             }
             assertEquals(POIFSConstants.END_OF_CHAIN, ministore.getNextBlock(50));
-
-            fs.close();
         }
+    }
 
+    @ParameterizedTest()
+    @MethodSource("get4kFileAndInput")
+    void propertiesAndFatOnRead4k(String file, Function<String,POIFSFileSystem> opener) throws IOException {
         // Now with a simple 4096 block file
-        fsA = new POIFSFileSystem(_inst.getFile("BlockSize4096.zvi"));
-        fsB = new POIFSFileSystem(_inst.openResourceAsStream("BlockSize4096.zvi"));
-        for (POIFSFileSystem fs : new POIFSFileSystem[]{fsA, fsB}) {
+        try (POIFSFileSystem fs = opener.apply(file)) {
             // Check the FAT was properly processed
             // Verify we only got one block
             fs.getBATBlockAndIndex(0);
@@ -1330,8 +1344,6 @@ final class TestPOIFSStream {
                 assertEquals(i + 1, ministore.getNextBlock(i));
             }
             assertEquals(POIFSConstants.END_OF_CHAIN, ministore.getNextBlock(50));
-
-            fs.close();
         }
     }
 
@@ -1339,11 +1351,10 @@ final class TestPOIFSStream {
      * Check that for a given block, we can correctly figure
      * out what the next one is
      */
-    @Test
-    void nextBlock() throws IOException {
-        POIFSFileSystem fsA = new POIFSFileSystem(_inst.getFile("BlockSize512.zvi"));
-        POIFSFileSystem fsB = new POIFSFileSystem(_inst.openResourceAsStream("BlockSize512.zvi"));
-        for (POIFSFileSystem fs : new POIFSFileSystem[]{fsA, fsB}) {
+    @ParameterizedTest()
+    @MethodSource("get512FileAndInput")
+    void nextBlock512(String file, Function<String,POIFSFileSystem> opener) throws IOException {
+        try (POIFSFileSystem fs = opener.apply(file)) {
             // 0 -> 21 are simple
             for (int i = 0; i < 21; i++) {
                 assertEquals(i + 1, fs.getNextBlock(i));
@@ -1375,14 +1386,14 @@ final class TestPOIFSStream {
             for (int i = 100; i < fs.getBigBlockSizeDetails().getBATEntriesPerBlock(); i++) {
                 assertEquals(POIFSConstants.UNUSED_BLOCK, fs.getNextBlock(i));
             }
-
-            fs.close();
         }
+    }
 
+    @ParameterizedTest()
+    @MethodSource("get4kFileAndInput")
+    void nextBlock4k(String file, Function<String,POIFSFileSystem> opener) throws IOException {
         // Quick check on 4096 byte blocks too
-        fsA = new POIFSFileSystem(_inst.getFile("BlockSize4096.zvi"));
-        fsB = new POIFSFileSystem(_inst.openResourceAsStream("BlockSize4096.zvi"));
-        for (POIFSFileSystem fs : new POIFSFileSystem[]{fsA, fsB}) {
+        try (POIFSFileSystem fs = opener.apply(file)) {
             // 0 -> 1 -> 2 -> end
             assertEquals(1, fs.getNextBlock(0));
             assertEquals(2, fs.getNextBlock(1));
@@ -1393,23 +1404,18 @@ final class TestPOIFSStream {
                 assertEquals(i + 1, fs.getNextBlock(i));
             }
             assertEquals(POIFSConstants.END_OF_CHAIN, fs.getNextBlock(11));
-
-            fs.close();
         }
     }
 
     /**
      * Check we get the right data back for each block
      */
-    @Test
-    void getBlock() throws IOException {
-        POIFSFileSystem fsA = new POIFSFileSystem(_inst.getFile("BlockSize512.zvi"));
-        POIFSFileSystem fsB = new POIFSFileSystem(_inst.openResourceAsStream("BlockSize512.zvi"));
-        for (POIFSFileSystem fs : new POIFSFileSystem[]{fsA, fsB}) {
-            ByteBuffer b;
-
+    @ParameterizedTest()
+    @MethodSource("get512FileAndInput")
+    void getBlock512(String file, Function<String,POIFSFileSystem> opener) throws IOException {
+        try (POIFSFileSystem fs = opener.apply(file)) {
             // The 0th block is the first data block
-            b = fs.getBlockAt(0);
+            ByteBuffer b = fs.getBlockAt(0);
             assertEquals((byte) 0x9e, b.get());
             assertEquals((byte) 0x75, b.get());
             assertEquals((byte) 0x97, b.get());
@@ -1432,18 +1438,16 @@ final class TestPOIFSStream {
             assertEquals((byte) 0x00, b.get());
             assertEquals((byte) 0x00, b.get());
             assertEquals((byte) 0x00, b.get());
-
-            fs.close();
         }
+    }
 
+    @ParameterizedTest()
+    @MethodSource("get4kFileAndInput")
+    void getBlock4k(String file, Function<String,POIFSFileSystem> opener) throws IOException {
         // Quick check on 4096 byte blocks too
-        fsA = new POIFSFileSystem(_inst.getFile("BlockSize4096.zvi"));
-        fsB = new POIFSFileSystem(_inst.openResourceAsStream("BlockSize4096.zvi"));
-        for (POIFSFileSystem fs : new POIFSFileSystem[]{fsA, fsB}) {
-            ByteBuffer b;
-
+        try (POIFSFileSystem fs = opener.apply(file)) {
             // The 0th block is the first data block
-            b = fs.getBlockAt(0);
+            ByteBuffer b = fs.getBlockAt(0);
             assertEquals((byte) 0x9e, b.get());
             assertEquals((byte) 0x75, b.get());
             assertEquals((byte) 0x97, b.get());
@@ -1466,8 +1470,6 @@ final class TestPOIFSStream {
             assertEquals((byte) 0x00, b.get());
             assertEquals((byte) 0x00, b.get());
             assertEquals((byte) 0x00, b.get());
-
-            fs.close();
         }
     }
 
@@ -1477,29 +1479,26 @@ final class TestPOIFSStream {
      */
     @Test
     void getFreeBlockWithSpare() throws IOException {
-        POIFSFileSystem fs = new POIFSFileSystem(_inst.getFile("BlockSize512.zvi"));
-
-        // Our first BAT block has spares
-        assertTrue(fs.getBATBlockAndIndex(0).getBlock().hasFreeSectors());
-
-        // First free one is 100
-        assertEquals(POIFSConstants.UNUSED_BLOCK, fs.getNextBlock(100));
-        assertEquals(POIFSConstants.UNUSED_BLOCK, fs.getNextBlock(101));
-        assertEquals(POIFSConstants.UNUSED_BLOCK, fs.getNextBlock(102));
-        assertEquals(POIFSConstants.UNUSED_BLOCK, fs.getNextBlock(103));
+        try (POIFSFileSystem fs = new POIFSFileSystem(_inst.getFile("BlockSize512.zvi"))) {
+            // Our first BAT block has spares
+            assertTrue(fs.getBATBlockAndIndex(0).getBlock().hasFreeSectors());
 
-        // Ask, will get 100
-        assertEquals(100, fs.getFreeBlock());
+            // First free one is 100
+            assertEquals(POIFSConstants.UNUSED_BLOCK, fs.getNextBlock(100));
+            assertEquals(POIFSConstants.UNUSED_BLOCK, fs.getNextBlock(101));
+            assertEquals(POIFSConstants.UNUSED_BLOCK, fs.getNextBlock(102));
+            assertEquals(POIFSConstants.UNUSED_BLOCK, fs.getNextBlock(103));
 
-        // Ask again, will still get 100 as not written to
-        assertEquals(100, fs.getFreeBlock());
+            // Ask, will get 100
+            assertEquals(100, fs.getFreeBlock());
 
-        // Allocate it, then ask again
-        fs.setNextBlock(100, POIFSConstants.END_OF_CHAIN);
-        assertEquals(101, fs.getFreeBlock());
+            // Ask again, will still get 100 as not written to
+            assertEquals(100, fs.getFreeBlock());
 
-        // All done
-        fs.close();
+            // Allocate it, then ask again
+            fs.setNextBlock(100, POIFSConstants.END_OF_CHAIN);
+            assertEquals(101, fs.getFreeBlock());
+        }
     }
 
     /**
@@ -1508,136 +1507,134 @@ final class TestPOIFSStream {
      */
     @Test
     void getFreeBlockWithNoneSpare() throws IOException {
-        POIFSFileSystem fs1 = new POIFSFileSystem(_inst.openResourceAsStream("BlockSize512.zvi"));
-        int free;
+        try (POIFSFileSystem fs1 = new POIFSFileSystem(_inst.openResourceAsStream("BlockSize512.zvi"))) {
+            int free;
 
-        // We have one BAT at block 99
-        assertEquals(POIFSConstants.FAT_SECTOR_BLOCK, fs1.getNextBlock(99));
-        assertBATCount(fs1, 1, 0);
+            // We have one BAT at block 99
+            assertEquals(POIFSConstants.FAT_SECTOR_BLOCK, fs1.getNextBlock(99));
+            assertBATCount(fs1, 1, 0);
 
-        // We've spare ones from 100 to 128
-        for (int i = 100; i < 128; i++) {
-            assertEquals(POIFSConstants.UNUSED_BLOCK, fs1.getNextBlock(i));
-        }
+            // We've spare ones from 100 to 128
+            for (int i = 100; i < 128; i++) {
+                assertEquals(POIFSConstants.UNUSED_BLOCK, fs1.getNextBlock(i));
+            }
 
-        // Check our BAT knows it's free
-        assertTrue(fs1.getBATBlockAndIndex(0).getBlock().hasFreeSectors());
+            // Check our BAT knows it's free
+            assertTrue(fs1.getBATBlockAndIndex(0).getBlock().hasFreeSectors());
 
-        // Allocate all the spare ones
-        for (int i = 100; i < 128; i++) {
-            fs1.setNextBlock(i, POIFSConstants.END_OF_CHAIN);
-        }
+            // Allocate all the spare ones
+            for (int i = 100; i < 128; i++) {
+                fs1.setNextBlock(i, POIFSConstants.END_OF_CHAIN);
+            }
 
-        // BAT is now full, but there's only the one
-        assertFalse(fs1.getBATBlockAndIndex(0).getBlock().hasFreeSectors());
-        assertThrows(IndexOutOfBoundsException.class, () -> fs1.getBATBlockAndIndex(128), "Should only be one BAT");
-        assertBATCount(fs1, 1, 0);
+            // BAT is now full, but there's only the one
+            assertFalse(fs1.getBATBlockAndIndex(0).getBlock().hasFreeSectors());
+            assertThrows(IndexOutOfBoundsException.class, () -> fs1.getBATBlockAndIndex(128), "Should only be one BAT");
+            assertBATCount(fs1, 1, 0);
 
 
-        // Now ask for a free one, will need to extend the file
-        assertEquals(129, fs1.getFreeBlock());
+            // Now ask for a free one, will need to extend the file
+            assertEquals(129, fs1.getFreeBlock());
 
-        assertFalse(fs1.getBATBlockAndIndex(0).getBlock().hasFreeSectors());
-        assertTrue(fs1.getBATBlockAndIndex(128).getBlock().hasFreeSectors());
-        assertEquals(POIFSConstants.FAT_SECTOR_BLOCK, fs1.getNextBlock(128));
-        assertEquals(POIFSConstants.UNUSED_BLOCK, fs1.getNextBlock(129));
+            assertFalse(fs1.getBATBlockAndIndex(0).getBlock().hasFreeSectors());
+            assertTrue(fs1.getBATBlockAndIndex(128).getBlock().hasFreeSectors());
+            assertEquals(POIFSConstants.FAT_SECTOR_BLOCK, fs1.getNextBlock(128));
+            assertEquals(POIFSConstants.UNUSED_BLOCK, fs1.getNextBlock(129));
 
-        // We now have 2 BATs, but no XBATs
-        assertBATCount(fs1, 2, 0);
+            // We now have 2 BATs, but no XBATs
+            assertBATCount(fs1, 2, 0);
 
 
-        // Fill up to hold 109 BAT blocks
-        for (int i = 0; i < 109; i++) {
-            fs1.getFreeBlock();
-            int startOffset = i * 128;
-            while (fs1.getBATBlockAndIndex(startOffset).getBlock().hasFreeSectors()) {
-                free = fs1.getFreeBlock();
-                fs1.setNextBlock(free, POIFSConstants.END_OF_CHAIN);
+            // Fill up to hold 109 BAT blocks
+            for (int i = 0; i < 109; i++) {
+                fs1.getFreeBlock();
+                int startOffset = i * 128;
+                while (fs1.getBATBlockAndIndex(startOffset).getBlock().hasFreeSectors()) {
+                    free = fs1.getFreeBlock();
+                    fs1.setNextBlock(free, POIFSConstants.END_OF_CHAIN);
+                }
             }
-        }
 
-        assertFalse(fs1.getBATBlockAndIndex(109 * 128 - 1).getBlock().hasFreeSectors());
-        assertThrows(IndexOutOfBoundsException.class, () -> fs1.getBATBlockAndIndex(109 * 128), "Should only be 109 BATs");
+            assertFalse(fs1.getBATBlockAndIndex(109 * 128 - 1).getBlock().hasFreeSectors());
+            assertThrows(IndexOutOfBoundsException.class, () -> fs1.getBATBlockAndIndex(109 * 128), "Should only be 109 BATs");
 
-        // We now have 109 BATs, but no XBATs
-        assertBATCount(fs1, 109, 0);
+            // We now have 109 BATs, but no XBATs
+            assertBATCount(fs1, 109, 0);
 
 
-        // Ask for it to be written out, and check the header
-        HeaderBlock header = writeOutAndReadHeader(fs1);
-        assertEquals(109, header.getBATCount());
-        assertEquals(0, header.getXBATCount());
+            // Ask for it to be written out, and check the header
+            HeaderBlock header = writeOutAndReadHeader(fs1);
+            assertEquals(109, header.getBATCount());
+            assertEquals(0, header.getXBATCount());
 
 
-        // Ask for another, will get our first XBAT
-        free = fs1.getFreeBlock();
-        assertTrue(free > 0, "Had: " + free);
+            // Ask for another, will get our first XBAT
+            free = fs1.getFreeBlock();
+            assertTrue(free > 0, "Had: " + free);
 
-        assertFalse(fs1.getBATBlockAndIndex(109 * 128 - 1).getBlock().hasFreeSectors());
-        assertTrue(fs1.getBATBlockAndIndex(110 * 128 - 1).getBlock().hasFreeSectors());
-        assertThrows(IndexOutOfBoundsException.class, () -> fs1.getBATBlockAndIndex(110 * 128), "Should only be 110 BATs");
-        assertBATCount(fs1, 110, 1);
+            assertFalse(fs1.getBATBlockAndIndex(109 * 128 - 1).getBlock().hasFreeSectors());
+            assertTrue(fs1.getBATBlockAndIndex(110 * 128 - 1).getBlock().hasFreeSectors());
+            assertThrows(IndexOutOfBoundsException.class, () -> fs1.getBATBlockAndIndex(110 * 128), "Should only be 110 BATs");
+            assertBATCount(fs1, 110, 1);
 
-        header = writeOutAndReadHeader(fs1);
-        assertEquals(110, header.getBATCount());
-        assertEquals(1, header.getXBATCount());
+            header = writeOutAndReadHeader(fs1);
+            assertEquals(110, header.getBATCount());
+            assertEquals(1, header.getXBATCount());
 
 
-        // Fill the XBAT, which means filling 127 BATs
-        for (int i = 109; i < 109 + 127; i++) {
-            fs1.getFreeBlock();
-            int startOffset = i * 128;
-            while (fs1.getBATBlockAndIndex(startOffset).getBlock().hasFreeSectors()) {
-                free = fs1.getFreeBlock();
-                fs1.setNextBlock(free, POIFSConstants.END_OF_CHAIN);
+            // Fill the XBAT, which means filling 127 BATs
+            for (int i = 109; i < 109 + 127; i++) {
+                fs1.getFreeBlock();
+                int startOffset = i * 128;
+                while (fs1.getBATBlockAndIndex(startOffset).getBlock().hasFreeSectors()) {
+                    free = fs1.getFreeBlock();
+                    fs1.setNextBlock(free, POIFSConstants.END_OF_CHAIN);
+                }
+                assertBATCount(fs1, i + 1, 1);
             }
-            assertBATCount(fs1, i + 1, 1);
-        }
-
-        // Should now have 109+127 = 236 BATs
-        assertFalse(fs1.getBATBlockAndIndex(236 * 128 - 1).getBlock().hasFreeSectors());
-        assertThrows(IndexOutOfBoundsException.class, () -> fs1.getBATBlockAndIndex(236 * 128), "Should only be 236 BATs");
-        assertBATCount(fs1, 236, 1);
-
 
-        // Ask for another, will get our 2nd XBAT
-        free = fs1.getFreeBlock();
-        assertTrue(free > 0, "Had: " + free);
+            // Should now have 109+127 = 236 BATs
+            assertFalse(fs1.getBATBlockAndIndex(236 * 128 - 1).getBlock().hasFreeSectors());
+            assertThrows(IndexOutOfBoundsException.class, () -> fs1.getBATBlockAndIndex(236 * 128), "Should only be 236 BATs");
+            assertBATCount(fs1, 236, 1);
 
-        assertFalse(fs1.getBATBlockAndIndex(236 * 128 - 1).getBlock().hasFreeSectors());
-        assertTrue(fs1.getBATBlockAndIndex(237 * 128 - 1).getBlock().hasFreeSectors());
-        assertThrows(IndexOutOfBoundsException.class, () -> fs1.getBATBlockAndIndex(237 * 128), "Should only be 237 BATs");
 
+            // Ask for another, will get our 2nd XBAT
+            free = fs1.getFreeBlock();
+            assertTrue(free > 0, "Had: " + free);
 
-        // Check the counts now
-        assertBATCount(fs1, 237, 2);
+            assertFalse(fs1.getBATBlockAndIndex(236 * 128 - 1).getBlock().hasFreeSectors());
+            assertTrue(fs1.getBATBlockAndIndex(237 * 128 - 1).getBlock().hasFreeSectors());
+            assertThrows(IndexOutOfBoundsException.class, () -> fs1.getBATBlockAndIndex(237 * 128), "Should only be 237 BATs");
 
-        // Check the header
-        header = writeOutAndReadHeader(fs1);
-        assertNotNull(header);
+            // Check the counts now
+            assertBATCount(fs1, 237, 2);
 
-        // Now, write it out, and read it back in again fully
-        POIFSFileSystem fs2 = writeOutAndReadBack(fs1);
-        fs1.close();
+            // Check the header
+            header = writeOutAndReadHeader(fs1);
+            assertNotNull(header);
 
-        // Check that it is seen correctly
-        assertBATCount(fs2, 237, 2);
+            // Now, write it out, and read it back in again fully
+            try (POIFSFileSystem fs2 = writeOutAndReadBack(fs1)) {
 
-        assertFalse(fs2.getBATBlockAndIndex(236 * 128 - 1).getBlock().hasFreeSectors());
-        assertTrue(fs2.getBATBlockAndIndex(237 * 128 - 1).getBlock().hasFreeSectors());
-        assertThrows(IndexOutOfBoundsException.class, () -> fs2.getBATBlockAndIndex(237 * 128), "Should only be 237 BATs");
+                // Check that it is seen correctly
+                assertBATCount(fs2, 237, 2);
 
-        // All done
-        fs2.close();
+                assertFalse(fs2.getBATBlockAndIndex(236 * 128 - 1).getBlock().hasFreeSectors());
+                assertTrue(fs2.getBATBlockAndIndex(237 * 128 - 1).getBlock().hasFreeSectors());
+                assertThrows(IndexOutOfBoundsException.class, () -> fs2.getBATBlockAndIndex(237 * 128), "Should only be 237 BATs");
+            }
+        }
     }
 
     /**
      * Test that we can correctly get the list of directory
      * entries, and the details on the files in them
      */
-    @Test
-    void listEntries() throws IOException {
-        for (POIFSFileSystem fs : get512and4kFileAndInput()) {
+    @ParameterizedTest
+    @MethodSource("get512and4kFileAndInput")
+    void listEntries(String file, Function<String,POIFSFileSystem> opener) throws IOException {
+        try (POIFSFileSystem fs = opener.apply(file)) {
             DirectoryEntry root = fs.getRoot();
             assertEquals(5, root.getEntryCount());
 
@@ -1665,8 +1662,6 @@ final class TestPOIFSStream {
             // Look inside another
             DirectoryEntry imageD = (DirectoryEntry) image;
             assertEquals(7, imageD.getEntryCount());
-
-            fs.close();
         }
     }
 
@@ -1674,9 +1669,11 @@ final class TestPOIFSStream {
      * Tests that we can get the correct contents for
      * a document in the filesystem
      */
-    @Test
-    void getDocumentEntry() throws Exception {
-        for (POIFSFileSystem fs : get512and4kFileAndInput()) {
+    @ParameterizedTest
+    @MethodSource("get512and4kFileAndInput")
+    void getDocumentEntry(String file, Function<String,POIFSFileSystem> opener)
+    throws IOException, NoPropertySetStreamException {
+        try (POIFSFileSystem fs = opener.apply(file)) {
             DirectoryEntry root = fs.getRoot();
             Entry si = root.getEntry("\u0005SummaryInformation");
 
@@ -1687,18 +1684,16 @@ final class TestPOIFSStream {
             assertContentsMatches(null, doc);
 
             // Now try to build the property set
-            DocumentInputStream inp = new DocumentInputStream(doc);
-            PropertySet ps = PropertySetFactory.create(inp);
-            SummaryInformation inf = (SummaryInformation) ps;
-
-            // Check some bits in it
-            assertNull(inf.getApplicationName());
-            assertNull(inf.getAuthor());
-            assertNull(inf.getSubject());
-            assertEquals(131333, inf.getOSVersion());
-
-            // Finish with this one
-            inp.close();
+            try (DocumentInputStream inp = new DocumentInputStream(doc)) {
+                PropertySet ps = PropertySetFactory.create(inp);
+                SummaryInformation inf = (SummaryInformation) ps;
+
+                // Check some bits in it
+                assertNull(inf.getApplicationName());
+                assertNull(inf.getAuthor());
+                assertNull(inf.getSubject());
+                assertEquals(131333, inf.getOSVersion());
+            }
 
 
             // Try the other summary information
@@ -1707,12 +1702,11 @@ final class TestPOIFSStream {
             doc = (DocumentNode) si;
             assertContentsMatches(null, doc);
 
-            inp = new DocumentInputStream(doc);
-            ps = PropertySetFactory.create(inp);
-            DocumentSummaryInformation dinf = (DocumentSummaryInformation) ps;
-            assertEquals(131333, dinf.getOSVersion());
-
-            fs.close();
+            try (DocumentInputStream inp = new DocumentInputStream(doc)) {
+                PropertySet ps = PropertySetFactory.create(inp);
+                DocumentSummaryInformation dinf = (DocumentSummaryInformation) ps;
+                assertEquals(131333, dinf.getOSVersion());
+            }
         }
     }
 
@@ -1720,13 +1714,14 @@ final class TestPOIFSStream {
      * Read a file, write it and read it again.
      * Then, alter+add some streams, write and read
      */
-    @Test
-    void readWriteRead() throws Exception {
+    @ParameterizedTest
+    @MethodSource("get512and4kFileAndInput")
+    void readWriteRead(String file, Function<String,POIFSFileSystem> opener) throws IOException, NoPropertySetStreamException {
         SummaryInformation sinf;
         DocumentSummaryInformation dinf;
         DirectoryEntry root, testDir;
 
-        for (POIFSFileSystem fs1 : get512and4kFileAndInput()) {
+        try (POIFSFileSystem fs1 = opener.apply(file)) {
             // Check we can find the entries we expect
             root = fs1.getRoot();
             assertEquals(5, root.getEntryCount());
@@ -1736,257 +1731,251 @@ final class TestPOIFSStream {
             assertThat(root.getEntryNames(), hasItem("\u0005DocumentSummaryInformation"));
             assertThat(root.getEntryNames(), hasItem("\u0005SummaryInformation"));
 
-
             // Write out, re-load
-            POIFSFileSystem fs2 = writeOutAndReadBack(fs1);
-            fs1.close();
+            try (POIFSFileSystem fs2 = writeOutAndReadBack(fs1)) {
+                // Check they're still there
+                root = fs2.getRoot();
+                assertEquals(5, root.getEntryCount());
+                assertThat(root.getEntryNames(), hasItem("Thumbnail"));
+                assertThat(root.getEntryNames(), hasItem("Image"));
+                assertThat(root.getEntryNames(), hasItem("Tags"));
+                assertThat(root.getEntryNames(), hasItem("\u0005DocumentSummaryInformation"));
+                assertThat(root.getEntryNames(), hasItem("\u0005SummaryInformation"));
 
-            // Check they're still there
-            root = fs2.getRoot();
-            assertEquals(5, root.getEntryCount());
-            assertThat(root.getEntryNames(), hasItem("Thumbnail"));
-            assertThat(root.getEntryNames(), hasItem("Image"));
-            assertThat(root.getEntryNames(), hasItem("Tags"));
-            assertThat(root.getEntryNames(), hasItem("\u0005DocumentSummaryInformation"));
-            assertThat(root.getEntryNames(), hasItem("\u0005SummaryInformation"));
 
+                // Check the contents of them - parse the summary block and check
+                sinf = (SummaryInformation) PropertySetFactory.create(new DocumentInputStream(
+                    (DocumentEntry) root.getEntry(SummaryInformation.DEFAULT_STREAM_NAME)));
+                assertEquals(131333, sinf.getOSVersion());
 
-            // Check the contents of them - parse the summary block and check
-            sinf = (SummaryInformation) PropertySetFactory.create(new DocumentInputStream(
-                (DocumentEntry) root.getEntry(SummaryInformation.DEFAULT_STREAM_NAME)));
-            assertEquals(131333, sinf.getOSVersion());
+                dinf = (DocumentSummaryInformation) PropertySetFactory.create(new DocumentInputStream(
+                    (DocumentEntry) root.getEntry(DocumentSummaryInformation.DEFAULT_STREAM_NAME)));
+                assertEquals(131333, dinf.getOSVersion());
 
-            dinf = (DocumentSummaryInformation) PropertySetFactory.create(new DocumentInputStream(
-                (DocumentEntry) root.getEntry(DocumentSummaryInformation.DEFAULT_STREAM_NAME)));
-            assertEquals(131333, dinf.getOSVersion());
 
+                // Add a test mini stream
+                testDir = root.createDirectory("Testing 123");
+                testDir.createDirectory("Testing 456");
+                testDir.createDirectory("Testing 789");
+                byte[] mini = new byte[]{42, 0, 1, 2, 3, 4, 42};
+                testDir.createDocument("Mini", new ByteArrayInputStream(mini));
 
-            // Add a test mini stream
-            testDir = root.createDirectory("Testing 123");
-            testDir.createDirectory("Testing 456");
-            testDir.createDirectory("Testing 789");
-            byte[] mini = new byte[]{42, 0, 1, 2, 3, 4, 42};
-            testDir.createDocument("Mini", new ByteArrayInputStream(mini));
 
+                // Write out, re-load
+                try (POIFSFileSystem fs3 = writeOutAndReadBack(fs2)) {
 
-            // Write out, re-load
-            POIFSFileSystem fs3 = writeOutAndReadBack(fs2);
-            fs2.close();
+                    root = fs3.getRoot();
+                    testDir = (DirectoryEntry) root.getEntry("Testing 123");
+                    assertEquals(6, root.getEntryCount());
+                    assertThat(root.getEntryNames(), hasItem("Thumbnail"));
+                    assertThat(root.getEntryNames(), hasItem("Image"));
+                    assertThat(root.getEntryNames(), hasItem("Tags"));
+                    assertThat(root.getEntryNames(), hasItem("Testing 123"));
+                    assertThat(root.getEntryNames(), hasItem("\u0005DocumentSummaryInformation"));
+                    assertThat(root.getEntryNames(), hasItem("\u0005SummaryInformation"));
 
-            root = fs3.getRoot();
-            testDir = (DirectoryEntry) root.getEntry("Testing 123");
-            assertEquals(6, root.getEntryCount());
-            assertThat(root.getEntryNames(), hasItem("Thumbnail"));
-            assertThat(root.getEntryNames(), hasItem("Image"));
-            assertThat(root.getEntryNames(), hasItem("Tags"));
-            assertThat(root.getEntryNames(), hasItem("Testing 123"));
-            assertThat(root.getEntryNames(), hasItem("\u0005DocumentSummaryInformation"));
-            assertThat(root.getEntryNames(), hasItem("\u0005SummaryInformation"));
 
+                    // Check old and new are there
+                    sinf = (SummaryInformation) PropertySetFactory.create(new DocumentInputStream(
+                        (DocumentEntry) root.getEntry(SummaryInformation.DEFAULT_STREAM_NAME)));
+                    assertEquals(131333, sinf.getOSVersion());
 
-            // Check old and new are there
-            sinf = (SummaryInformation) PropertySetFactory.create(new DocumentInputStream(
-                (DocumentEntry) root.getEntry(SummaryInformation.DEFAULT_STREAM_NAME)));
-            assertEquals(131333, sinf.getOSVersion());
+                    dinf = (DocumentSummaryInformation) PropertySetFactory.create(new DocumentInputStream(
+                        (DocumentEntry) root.getEntry(DocumentSummaryInformation.DEFAULT_STREAM_NAME)));
+                    assertEquals(131333, dinf.getOSVersion());
 
-            dinf = (DocumentSummaryInformation) PropertySetFactory.create(new DocumentInputStream(
-                (DocumentEntry) root.getEntry(DocumentSummaryInformation.DEFAULT_STREAM_NAME)));
-            assertEquals(131333, dinf.getOSVersion());
+                    assertContentsMatches(mini, (DocumentEntry) testDir.getEntry("Mini"));
 
-            assertContentsMatches(mini, (DocumentEntry) testDir.getEntry("Mini"));
 
+                    // Write out and read once more, just to be sure
+                    try (POIFSFileSystem fs4 = writeOutAndReadBack(fs3)) {
 
-            // Write out and read once more, just to be sure
-            POIFSFileSystem fs4 = writeOutAndReadBack(fs3);
-            fs3.close();
+                        root = fs4.getRoot();
+                        testDir = (DirectoryEntry) root.getEntry("Testing 123");
+                        assertEquals(6, root.getEntryCount());
+                        assertThat(root.getEntryNames(), hasItem("Thumbnail"));
+                        assertThat(root.getEntryNames(), hasItem("Image"));
+                        assertThat(root.getEntryNames(), hasItem("Tags"));
+                        assertThat(root.getEntryNames(), hasItem("Testing 123"));
+                        assertThat(root.getEntryNames(), hasItem("\u0005DocumentSummaryInformation"));
+                        assertThat(root.getEntryNames(), hasItem("\u0005SummaryInformation"));
 
-            root = fs4.getRoot();
-            testDir = (DirectoryEntry) root.getEntry("Testing 123");
-            assertEquals(6, root.getEntryCount());
-            assertThat(root.getEntryNames(), hasItem("Thumbnail"));
-            assertThat(root.getEntryNames(), hasItem("Image"));
-            assertThat(root.getEntryNames(), hasItem("Tags"));
-            assertThat(root.getEntryNames(), hasItem("Testing 123"));
-            assertThat(root.getEntryNames(), hasItem("\u0005DocumentSummaryInformation"));
-            assertThat(root.getEntryNames(), hasItem("\u0005SummaryInformation"));
+                        sinf = (SummaryInformation) PropertySetFactory.create(new DocumentInputStream(
+                            (DocumentEntry) root.getEntry(SummaryInformation.DEFAULT_STREAM_NAME)));
+                        assertEquals(131333, sinf.getOSVersion());
 
-            sinf = (SummaryInformation) PropertySetFactory.create(new DocumentInputStream(
-                (DocumentEntry) root.getEntry(SummaryInformation.DEFAULT_STREAM_NAME)));
-            assertEquals(131333, sinf.getOSVersion());
+                        dinf = (DocumentSummaryInformation) PropertySetFactory.create(new DocumentInputStream(
+                            (DocumentEntry) root.getEntry(DocumentSummaryInformation.DEFAULT_STREAM_NAME)));
+                        assertEquals(131333, dinf.getOSVersion());
 
-            dinf = (DocumentSummaryInformation) PropertySetFactory.create(new DocumentInputStream(
-                (DocumentEntry) root.getEntry(DocumentSummaryInformation.DEFAULT_STREAM_NAME)));
-            assertEquals(131333, dinf.getOSVersion());
+                        assertContentsMatches(mini, (DocumentEntry) testDir.getEntry("Mini"));
 
-            assertContentsMatches(mini, (DocumentEntry) testDir.getEntry("Mini"));
 
+                        // Add a full stream, delete a full stream
+                        byte[] main4096 = new byte[4096];
+                        main4096[0] = -10;
+                        main4096[4095] = -11;
+                        testDir.createDocument("Normal4096", new ByteArrayInputStream(main4096));
 
-            // Add a full stream, delete a full stream
-            byte[] main4096 = new byte[4096];
-            main4096[0] = -10;
-            main4096[4095] = -11;
-            testDir.createDocument("Normal4096", new ByteArrayInputStream(main4096));
-
-            root.getEntry("Tags").delete();
-
-
-            // Write out, re-load
-            POIFSFileSystem fs5 = writeOutAndReadBack(fs4);
-            fs4.close();
-
-            // Check it's all there
-            root = fs5.getRoot();
-            testDir = (DirectoryEntry) root.getEntry("Testing 123");
-            assertEquals(5, root.getEntryCount());
-            assertThat(root.getEntryNames(), hasItem("Thumbnail"));
-            assertThat(root.getEntryNames(), hasItem("Image"));
-            assertThat(root.getEntryNames(), hasItem("Testing 123"));
-            assertThat(root.getEntryNames(), hasItem("\u0005DocumentSummaryInformation"));
-            assertThat(root.getEntryNames(), hasItem("\u0005SummaryInformation"));
+                        root.getEntry("Tags").delete();
 
 
-            // Check old and new are there
-            sinf = (SummaryInformation) PropertySetFactory.create(new DocumentInputStream(
-                (DocumentEntry) root.getEntry(SummaryInformation.DEFAULT_STREAM_NAME)));
-            assertEquals(131333, sinf.getOSVersion());
+                        // Write out, re-load
+                        try (POIFSFileSystem fs5 = writeOutAndReadBack(fs4)) {
 
-            dinf = (DocumentSummaryInformation) PropertySetFactory.create(new DocumentInputStream(
-                (DocumentEntry) root.getEntry(DocumentSummaryInformation.DEFAULT_STREAM_NAME)));
-            assertEquals(131333, dinf.getOSVersion());
+                            // Check it's all there
+                            root = fs5.getRoot();
+                            testDir = (DirectoryEntry) root.getEntry("Testing 123");
+                            assertEquals(5, root.getEntryCount());
+                            assertThat(root.getEntryNames(), hasItem("Thumbnail"));
+                            assertThat(root.getEntryNames(), hasItem("Image"));
+                            assertThat(root.getEntryNames(), hasItem("Testing 123"));
+                            assertThat(root.getEntryNames(), hasItem("\u0005DocumentSummaryInformation"));
+                            assertThat(root.getEntryNames(), hasItem("\u0005SummaryInformation"));
 
-            assertContentsMatches(mini, (DocumentEntry) testDir.getEntry("Mini"));
-            assertContentsMatches(main4096, (DocumentEntry) testDir.getEntry("Normal4096"));
 
+                            // Check old and new are there
+                            sinf = (SummaryInformation) PropertySetFactory.create(new DocumentInputStream(
+                                (DocumentEntry) root.getEntry(SummaryInformation.DEFAULT_STREAM_NAME)));
+                            assertEquals(131333, sinf.getOSVersion());
 
-            // Delete a directory, and add one more
-            testDir.getEntry("Testing 456").delete();
-            testDir.createDirectory("Testing ABC");
+                            dinf = (DocumentSummaryInformation) PropertySetFactory.create(new DocumentInputStream(
+                                (DocumentEntry) root.getEntry(DocumentSummaryInformation.DEFAULT_STREAM_NAME)));
+                            assertEquals(131333, dinf.getOSVersion());
 
+                            assertContentsMatches(mini, (DocumentEntry) testDir.getEntry("Mini"));
+                            assertContentsMatches(main4096, (DocumentEntry) testDir.getEntry("Normal4096"));
 
-            // Save
-            POIFSFileSystem fs6 = writeOutAndReadBack(fs5);
-            fs5.close();
 
-            // Check
-            root = fs6.getRoot();
-            testDir = (DirectoryEntry) root.getEntry("Testing 123");
-
-            assertEquals(5, root.getEntryCount());
-            assertThat(root.getEntryNames(), hasItem("Thumbnail"));
-            assertThat(root.getEntryNames(), hasItem("Image"));
-            assertThat(root.getEntryNames(), hasItem("Testing 123"));
-            assertThat(root.getEntryNames(), hasItem("\u0005DocumentSummaryInformation"));
-            assertThat(root.getEntryNames(), hasItem("\u0005SummaryInformation"));
-
-            assertEquals(4, testDir.getEntryCount());
-            assertThat(testDir.getEntryNames(), hasItem("Mini"));
-            assertThat(testDir.getEntryNames(), hasItem("Normal4096"));
-            assertThat(testDir.getEntryNames(), hasItem("Testing 789"));
-            assertThat(testDir.getEntryNames(), hasItem("Testing ABC"));
-
-
-            // Add another mini stream
-            byte[] mini2 = new byte[]{-42, 0, -1, -2, -3, -4, -42};
-            testDir.createDocument("Mini2", new ByteArrayInputStream(mini2));
+                            // Delete a directory, and add one more
+                            testDir.getEntry("Testing 456").delete();
+                            testDir.createDirectory("Testing ABC");
 
-            // Save, load, check
-            POIFSFileSystem fs7 = writeOutAndReadBack(fs6);
-            fs6.close();
 
-            root = fs7.getRoot();
-            testDir = (DirectoryEntry) root.getEntry("Testing 123");
+                            // Save
+                            try (POIFSFileSystem fs6 = writeOutAndReadBack(fs5)) {
 
-            assertEquals(5, root.getEntryCount());
-            assertThat(root.getEntryNames(), hasItem("Thumbnail"));
-            assertThat(root.getEntryNames(), hasItem("Image"));
-            assertThat(root.getEntryNames(), hasItem("Testing 123"));
-            assertThat(root.getEntryNames(), hasItem("\u0005DocumentSummaryInformation"));
-            assertThat(root.getEntryNames(), hasItem("\u0005SummaryInformation"));
+                                // Check
+                                root = fs6.getRoot();
+                                testDir = (DirectoryEntry) root.getEntry("Testing 123");
 
-            assertEquals(5, testDir.getEntryCount());
-            assertThat(testDir.getEntryNames(), hasItem("Mini"));
-            assertThat(testDir.getEntryNames(), hasItem("Mini2"));
-            assertThat(testDir.getEntryNames(), hasItem("Normal4096"));
-            assertThat(testDir.getEntryNames(), hasItem("Testing 789"));
-            assertThat(testDir.getEntryNames(), hasItem("Testing ABC"));
+                                assertEquals(5, root.getEntryCount());
+                                assertThat(root.getEntryNames(), hasItem("Thumbnail"));
+                                assertThat(root.getEntryNames(), hasItem("Image"));
+                                assertThat(root.getEntryNames(), hasItem("Testing 123"));
+                                assertThat(root.getEntryNames(), hasItem("\u0005DocumentSummaryInformation"));
+                                assertThat(root.getEntryNames(), hasItem("\u0005SummaryInformation"));
 
-            assertContentsMatches(mini, (DocumentEntry) testDir.getEntry("Mini"));
-            assertContentsMatches(mini2, (DocumentEntry) testDir.getEntry("Mini2"));
-            assertContentsMatches(main4096, (DocumentEntry) testDir.getEntry("Normal4096"));
+                                assertEquals(4, testDir.getEntryCount());
+                                assertThat(testDir.getEntryNames(), hasItem("Mini"));
+                                assertThat(testDir.getEntryNames(), hasItem("Normal4096"));
+                                assertThat(testDir.getEntryNames(), hasItem("Testing 789"));
+                                assertThat(testDir.getEntryNames(), hasItem("Testing ABC"));
 
 
-            // Delete a mini stream, add one more
-            testDir.getEntry("Mini").delete();
+                                // Add another mini stream
+                                byte[] mini2 = new byte[]{-42, 0, -1, -2, -3, -4, -42};
+                                testDir.createDocument("Mini2", new ByteArrayInputStream(mini2));
 
-            byte[] mini3 = new byte[]{42, 0, 42, 0, 42, 0, 42};
-            testDir.createDocument("Mini3", new ByteArrayInputStream(mini3));
+                                // Save, load, check
+                                try (POIFSFileSystem fs7 = writeOutAndReadBack(fs6)) {
 
+                                    root = fs7.getRoot();
+                                    testDir = (DirectoryEntry) root.getEntry("Testing 123");
 
-            // Save, load, check
-            POIFSFileSystem fs8 = writeOutAndReadBack(fs7);
-            fs7.close();
+                                    assertEquals(5, root.getEntryCount());
+                                    assertThat(root.getEntryNames(), hasItem("Thumbnail"));
+                                    assertThat(root.getEntryNames(), hasItem("Image"));
+                                    assertThat(root.getEntryNames(), hasItem("Testing 123"));
+                                    assertThat(root.getEntryNames(), hasItem("\u0005DocumentSummaryInformation"));
+                                    assertThat(root.getEntryNames(), hasItem("\u0005SummaryInformation"));
 
-            root = fs8.getRoot();
-            testDir = (DirectoryEntry) root.getEntry("Testing 123");
+                                    assertEquals(5, testDir.getEntryCount());
+                                    assertThat(testDir.getEntryNames(), hasItem("Mini"));
+                                    assertThat(testDir.getEntryNames(), hasItem("Mini2"));
+                                    assertThat(testDir.getEntryNames(), hasItem("Normal4096"));
+                                    assertThat(testDir.getEntryNames(), hasItem("Testing 789"));
+                                    assertThat(testDir.getEntryNames(), hasItem("Testing ABC"));
 
-            assertEquals(5, root.getEntryCount());
-            assertThat(root.getEntryNames(), hasItem("Thumbnail"));
-            assertThat(root.getEntryNames(), hasItem("Image"));
-            assertThat(root.getEntryNames(), hasItem("Testing 123"));
-            assertThat(root.getEntryNames(), hasItem("\u0005DocumentSummaryInformation"));
-            assertThat(root.getEntryNames(), hasItem("\u0005SummaryInformation"));
+                                    assertContentsMatches(mini, (DocumentEntry) testDir.getEntry("Mini"));
+                                    assertContentsMatches(mini2, (DocumentEntry) testDir.getEntry("Mini2"));
+                                    assertContentsMatches(main4096, (DocumentEntry) testDir.getEntry("Normal4096"));
 
-            assertEquals(5, testDir.getEntryCount());
-            assertThat(testDir.getEntryNames(), hasItem("Mini2"));
-            assertThat(testDir.getEntryNames(), hasItem("Mini3"));
-            assertThat(testDir.getEntryNames(), hasItem("Normal4096"));
-            assertThat(testDir.getEntryNames(), hasItem("Testing 789"));
-            assertThat(testDir.getEntryNames(), hasItem("Testing ABC"));
 
-            assertContentsMatches(mini2, (DocumentEntry) testDir.getEntry("Mini2"));
-            assertContentsMatches(mini3, (DocumentEntry) testDir.getEntry("Mini3"));
-            assertContentsMatches(main4096, (DocumentEntry) testDir.getEntry("Normal4096"));
+                                    // Delete a mini stream, add one more
+                                    testDir.getEntry("Mini").delete();
 
+                                    byte[] mini3 = new byte[]{42, 0, 42, 0, 42, 0, 42};
+                                    testDir.createDocument("Mini3", new ByteArrayInputStream(mini3));
 
-            // Change some existing streams
-            POIFSDocument mini2Doc = new POIFSDocument((DocumentNode) testDir.getEntry("Mini2"));
-            mini2Doc.replaceContents(new ByteArrayInputStream(mini));
 
-            byte[] main4106 = new byte[4106];
-            main4106[0] = 41;
-            main4106[4105] = 42;
-            POIFSDocument mainDoc = new POIFSDocument((DocumentNode) testDir.getEntry("Normal4096"));
-            mainDoc.replaceContents(new ByteArrayInputStream(main4106));
+                                    // Save, load, check
+                                    try (POIFSFileSystem fs8 = writeOutAndReadBack(fs7)) {
 
+                                        root = fs8.getRoot();
+                                        testDir = (DirectoryEntry) root.getEntry("Testing 123");
 
-            // Re-check
-            POIFSFileSystem fs9 = writeOutAndReadBack(fs8);
-            fs8.close();
+                                        assertEquals(5, root.getEntryCount());
+                                        assertThat(root.getEntryNames(), hasItem("Thumbnail"));
+                                        assertThat(root.getEntryNames(), hasItem("Image"));
+                                        assertThat(root.getEntryNames(), hasItem("Testing 123"));
+                                        assertThat(root.getEntryNames(), hasItem("\u0005DocumentSummaryInformation"));
+                                        assertThat(root.getEntryNames(), hasItem("\u0005SummaryInformation"));
+
+                                        assertEquals(5, testDir.getEntryCount());
+                                        assertThat(testDir.getEntryNames(), hasItem("Mini2"));
+                                        assertThat(testDir.getEntryNames(), hasItem("Mini3"));
+                                        assertThat(testDir.getEntryNames(), hasItem("Normal4096"));
+                                        assertThat(testDir.getEntryNames(), hasItem("Testing 789"));
+                                        assertThat(testDir.getEntryNames(), hasItem("Testing ABC"));
 
-            root = fs9.getRoot();
-            testDir = (DirectoryEntry) root.getEntry("Testing 123");
+                                        assertContentsMatches(mini2, (DocumentEntry) testDir.getEntry("Mini2"));
+                                        assertContentsMatches(mini3, (DocumentEntry) testDir.getEntry("Mini3"));
+                                        assertContentsMatches(main4096, (DocumentEntry) testDir.getEntry("Normal4096"));
 
-            assertEquals(5, root.getEntryCount());
-            assertThat(root.getEntryNames(), hasItem("Thumbnail"));
-            assertThat(root.getEntryNames(), hasItem("Image"));
-            assertThat(root.getEntryNames(), hasItem("Testing 123"));
-            assertThat(root.getEntryNames(), hasItem("\u0005DocumentSummaryInformation"));
-            assertThat(root.getEntryNames(), hasItem("\u0005SummaryInformation"));
 
-            assertEquals(5, testDir.getEntryCount());
-            assertThat(testDir.getEntryNames(), hasItem("Mini2"));
-            assertThat(testDir.getEntryNames(), hasItem("Mini3"));
-            assertThat(testDir.getEntryNames(), hasItem("Normal4096"));
-            assertThat(testDir.getEntryNames(), hasItem("Testing 789"));
-            assertThat(testDir.getEntryNames(), hasItem("Testing ABC"));
+                                        // Change some existing streams
+                                        POIFSDocument mini2Doc = new POIFSDocument((DocumentNode) testDir.getEntry("Mini2"));
+                                        mini2Doc.replaceContents(new ByteArrayInputStream(mini));
 
-            assertContentsMatches(mini, (DocumentEntry) testDir.getEntry("Mini2"));
-            assertContentsMatches(mini3, (DocumentEntry) testDir.getEntry("Mini3"));
-            assertContentsMatches(main4106, (DocumentEntry) testDir.getEntry("Normal4096"));
+                                        byte[] main4106 = new byte[4106];
+                                        main4106[0] = 41;
+                                        main4106[4105] = 42;
+                                        POIFSDocument mainDoc = new POIFSDocument((DocumentNode) testDir.getEntry("Normal4096"));
+                                        mainDoc.replaceContents(new ByteArrayInputStream(main4106));
 
 
-            // All done
-            fs9.close();
+                                        // Re-check
+                                        try (POIFSFileSystem fs9 = writeOutAndReadBack(fs8)) {
+
+                                            root = fs9.getRoot();
+                                            testDir = (DirectoryEntry) root.getEntry("Testing 123");
+
+                                            assertEquals(5, root.getEntryCount());
+                                            assertThat(root.getEntryNames(), hasItem("Thumbnail"));
+                                            assertThat(root.getEntryNames(), hasItem("Image"));
+                                            assertThat(root.getEntryNames(), hasItem("Testing 123"));
+                                            assertThat(root.getEntryNames(), hasItem("\u0005DocumentSummaryInformation"));
+                                            assertThat(root.getEntryNames(), hasItem("\u0005SummaryInformation"));
+
+                                            assertEquals(5, testDir.getEntryCount());
+                                            assertThat(testDir.getEntryNames(), hasItem("Mini2"));
+                                            assertThat(testDir.getEntryNames(), hasItem("Mini3"));
+                                            assertThat(testDir.getEntryNames(), hasItem("Normal4096"));
+                                            assertThat(testDir.getEntryNames(), hasItem("Testing 789"));
+                                            assertThat(testDir.getEntryNames(), hasItem("Testing ABC"));
+
+                                            assertContentsMatches(mini, (DocumentEntry) testDir.getEntry("Mini2"));
+                                            assertContentsMatches(mini3, (DocumentEntry) testDir.getEntry("Mini3"));
+                                            assertContentsMatches(main4106, (DocumentEntry) testDir.getEntry("Normal4096"));
+                                        }
+                                    }
+                                }
+                            }
+                        }
+                    }
+                }
+            }
         }
     }
 
@@ -1996,528 +1985,510 @@ final class TestPOIFSStream {
      */
     @Test
     void createWriteRead() throws IOException {
-        POIFSFileSystem fs1 = new POIFSFileSystem();
-        DocumentEntry miniDoc;
-        DocumentEntry normDoc;
-
-        // Initially has Properties + BAT but not SBAT
-        assertEquals(POIFSConstants.END_OF_CHAIN, fs1.getNextBlock(0));
-        assertEquals(POIFSConstants.FAT_SECTOR_BLOCK, fs1.getNextBlock(1));
-        assertEquals(POIFSConstants.UNUSED_BLOCK, fs1.getNextBlock(2));
-
-        // Check that the SBAT is empty
-        assertEquals(POIFSConstants.END_OF_CHAIN, fs1.getRoot().getProperty().getStartBlock());
-
-        // Check that properties table was given block 0
-        assertEquals(0, fs1._get_property_table().getStartBlock());
-
-        // Write and read it
-        POIFSFileSystem fs2 = writeOutAndReadBack(fs1);
-        fs1.close();
-
-        // No change, SBAT remains empty
-        assertEquals(POIFSConstants.END_OF_CHAIN, fs2.getNextBlock(0));
-        assertEquals(POIFSConstants.FAT_SECTOR_BLOCK, fs2.getNextBlock(1));
-        assertEquals(POIFSConstants.UNUSED_BLOCK, fs2.getNextBlock(2));
-        assertEquals(POIFSConstants.UNUSED_BLOCK, fs2.getNextBlock(3));
-        assertEquals(POIFSConstants.END_OF_CHAIN, fs2.getRoot().getProperty().getStartBlock());
-        assertEquals(0, fs2._get_property_table().getStartBlock());
-        fs2.close();
+        try (POIFSFileSystem fs1 = new POIFSFileSystem()) {
+            // Initially has Properties + BAT but not SBAT
+            assertEquals(POIFSConstants.END_OF_CHAIN, fs1.getNextBlock(0));
+            assertEquals(POIFSConstants.FAT_SECTOR_BLOCK, fs1.getNextBlock(1));
+            assertEquals(POIFSConstants.UNUSED_BLOCK, fs1.getNextBlock(2));
+
+            // Check that the SBAT is empty
+            assertEquals(POIFSConstants.END_OF_CHAIN, fs1.getRoot().getProperty().getStartBlock());
+
+            // Check that properties table was given block 0
+            assertEquals(0, fs1._get_property_table().getStartBlock());
+
+            // Write and read it
+            try (POIFSFileSystem fs2 = writeOutAndReadBack(fs1)) {
+
+                // No change, SBAT remains empty
+                assertEquals(POIFSConstants.END_OF_CHAIN, fs2.getNextBlock(0));
+                assertEquals(POIFSConstants.FAT_SECTOR_BLOCK, fs2.getNextBlock(1));
+                assertEquals(POIFSConstants.UNUSED_BLOCK, fs2.getNextBlock(2));
+                assertEquals(POIFSConstants.UNUSED_BLOCK, fs2.getNextBlock(3));
+                assertEquals(POIFSConstants.END_OF_CHAIN, fs2.getRoot().getProperty().getStartBlock());
+                assertEquals(0, fs2._get_property_table().getStartBlock());
+            }
+        }
 
         // Check the same but with saving to a file
-        POIFSFileSystem fs3 = new POIFSFileSystem();
-        POIFSFileSystem fs4 = writeOutFileAndReadBack(fs3);
-        fs3.close();
-
-        // Same, no change, SBAT remains empty
-        assertEquals(POIFSConstants.END_OF_CHAIN, fs4.getNextBlock(0));
-        assertEquals(POIFSConstants.FAT_SECTOR_BLOCK, fs4.getNextBlock(1));
-        assertEquals(POIFSConstants.UNUSED_BLOCK, fs4.getNextBlock(2));
-        assertEquals(POIFSConstants.UNUSED_BLOCK, fs4.getNextBlock(3));
-        assertEquals(POIFSConstants.END_OF_CHAIN, fs4.getRoot().getProperty().getStartBlock());
-        assertEquals(0, fs4._get_property_table().getStartBlock());
-
-
-        // Put everything within a new directory
-        DirectoryEntry testDir = fs4.createDirectory("Test Directory");
-
-        // Add a new Normal Stream (Normal Streams minimum 4096 bytes)
-        byte[] main4096 = new byte[4096];
-        main4096[0] = -10;
-        main4096[4095] = -11;
-        testDir.createDocument("Normal4096", new ByteArrayInputStream(main4096));
-
-        assertEquals(POIFSConstants.END_OF_CHAIN, fs4.getNextBlock(0));
-        assertEquals(POIFSConstants.FAT_SECTOR_BLOCK, fs4.getNextBlock(1));
-        assertEquals(3, fs4.getNextBlock(2));
-        assertEquals(4, fs4.getNextBlock(3));
-        assertEquals(5, fs4.getNextBlock(4));
-        assertEquals(6, fs4.getNextBlock(5));
-        assertEquals(7, fs4.getNextBlock(6));
-        assertEquals(8, fs4.getNextBlock(7));
-        assertEquals(9, fs4.getNextBlock(8));
-        assertEquals(POIFSConstants.END_OF_CHAIN, fs4.getNextBlock(9));
-        assertEquals(POIFSConstants.UNUSED_BLOCK, fs4.getNextBlock(10));
-        assertEquals(POIFSConstants.UNUSED_BLOCK, fs4.getNextBlock(11));
-        // SBAT still unused
-        assertEquals(POIFSConstants.END_OF_CHAIN, fs4.getRoot().getProperty().getStartBlock());
-
-
-        // Add a bigger Normal Stream
-        byte[] main5124 = new byte[5124];
-        main5124[0] = -22;
-        main5124[5123] = -33;
-        testDir.createDocument("Normal5124", new ByteArrayInputStream(main5124));
-
-        assertEquals(POIFSConstants.END_OF_CHAIN, fs4.getNextBlock(0));
-        assertEquals(POIFSConstants.FAT_SECTOR_BLOCK, fs4.getNextBlock(1));
-        assertEquals(3, fs4.getNextBlock(2));
-        assertEquals(4, fs4.getNextBlock(3));
-        assertEquals(5, fs4.getNextBlock(4));
-        assertEquals(6, fs4.getNextBlock(5));
-        assertEquals(7, fs4.getNextBlock(6));
-        assertEquals(8, fs4.getNextBlock(7));
-        assertEquals(9, fs4.getNextBlock(8));
-        assertEquals(POIFSConstants.END_OF_CHAIN, fs4.getNextBlock(9));
-
-        assertEquals(11, fs4.getNextBlock(10));
-        assertEquals(12, fs4.getNextBlock(11));
-        assertEquals(13, fs4.getNextBlock(12));
-        assertEquals(14, fs4.getNextBlock(13));
-        assertEquals(15, fs4.getNextBlock(14));
-        assertEquals(16, fs4.getNextBlock(15));
-        assertEquals(17, fs4.getNextBlock(16));
-        assertEquals(18, fs4.getNextBlock(17));
-        assertEquals(19, fs4.getNextBlock(18));
-        assertEquals(20, fs4.getNextBlock(19));
-        assertEquals(POIFSConstants.END_OF_CHAIN, fs4.getNextBlock(20));
-        assertEquals(POIFSConstants.UNUSED_BLOCK, fs4.getNextBlock(21));
-        assertEquals(POIFSConstants.UNUSED_BLOCK, fs4.getNextBlock(22));
-
-        assertEquals(POIFSConstants.END_OF_CHAIN, fs4.getRoot().getProperty().getStartBlock());
-
-
-        // Now Add a mini stream
-        byte[] mini = new byte[]{42, 0, 1, 2, 3, 4, 42};
-        testDir.createDocument("Mini", new ByteArrayInputStream(mini));
-
-        // Mini stream will get one block for fat + one block for data
-        assertEquals(POIFSConstants.END_OF_CHAIN, fs4.getNextBlock(0));
-        assertEquals(POIFSConstants.FAT_SECTOR_BLOCK, fs4.getNextBlock(1));
-        assertEquals(3, fs4.getNextBlock(2));
-        assertEquals(4, fs4.getNextBlock(3));
-        assertEquals(5, fs4.getNextBlock(4));
-        assertEquals(6, fs4.getNextBlock(5));
-        assertEquals(7, fs4.getNextBlock(6));
-        assertEquals(8, fs4.getNextBlock(7));
-        assertEquals(9, fs4.getNextBlock(8));
-        assertEquals(POIFSConstants.END_OF_CHAIN, fs4.getNextBlock(9));
-
-        assertEquals(11, fs4.getNextBlock(10));
-        assertEquals(12, fs4.getNextBlock(11));
-        assertEquals(13, fs4.getNextBlock(12));
-        assertEquals(14, fs4.getNextBlock(13));
-        assertEquals(15, fs4.getNextBlock(14));
-        assertEquals(16, fs4.getNextBlock(15));
-        assertEquals(17, fs4.getNextBlock(16));
-        assertEquals(18, fs4.getNextBlock(17));
-        assertEquals(19, fs4.getNextBlock(18));
-        assertEquals(20, fs4.getNextBlock(19));
-        assertEquals(POIFSConstants.END_OF_CHAIN, fs4.getNextBlock(20));
-        assertEquals(POIFSConstants.END_OF_CHAIN, fs4.getNextBlock(21));
-        assertEquals(POIFSConstants.END_OF_CHAIN, fs4.getNextBlock(22));
-        assertEquals(POIFSConstants.UNUSED_BLOCK, fs4.getNextBlock(23));
-
-        // Check the mini stream location was set
-        // (21 is mini fat, 22 is first mini stream block)
-        assertEquals(22, fs4.getRoot().getProperty().getStartBlock());
-
-
-        // Write and read back
-        POIFSFileSystem fs5 = writeOutAndReadBack(fs4);
-        fs4.close();
-        HeaderBlock header = writeOutAndReadHeader(fs5);
-
-        // Check the header has the right points in it
-        assertEquals(1, header.getBATCount());
-        assertEquals(1, header.getBATArray()[0]);
-        assertEquals(0, header.getPropertyStart());
-        assertEquals(1, header.getSBATCount());
-        assertEquals(21, header.getSBATStart());
-        assertEquals(22, fs5._get_property_table().getRoot().getStartBlock());
-
-        // Block use should be almost the same, except the properties
-        //  stream will have grown out to cover 2 blocks
-        // Check the block use is all unchanged
-        assertEquals(23, fs5.getNextBlock(0)); // Properties now extends over 2 blocks
-        assertEquals(POIFSConstants.FAT_SECTOR_BLOCK, fs5.getNextBlock(1));
-
-        assertEquals(3, fs5.getNextBlock(2));
-        assertEquals(4, fs5.getNextBlock(3));
-        assertEquals(5, fs5.getNextBlock(4));
-        assertEquals(6, fs5.getNextBlock(5));
-        assertEquals(7, fs5.getNextBlock(6));
-        assertEquals(8, fs5.getNextBlock(7));
-        assertEquals(9, fs5.getNextBlock(8));
-        assertEquals(POIFSConstants.END_OF_CHAIN, fs5.getNextBlock(9)); // End of normal4096
-
-        assertEquals(11, fs5.getNextBlock(10));
-        assertEquals(12, fs5.getNextBlock(11));
-        assertEquals(13, fs5.getNextBlock(12));
-        assertEquals(14, fs5.getNextBlock(13));
-        assertEquals(15, fs5.getNextBlock(14));
-        assertEquals(16, fs5.getNextBlock(15));
-        assertEquals(17, fs5.getNextBlock(16));
-        assertEquals(18, fs5.getNextBlock(17));
-        assertEquals(19, fs5.getNextBlock(18));
-        assertEquals(20, fs5.getNextBlock(19));
-        assertEquals(POIFSConstants.END_OF_CHAIN, fs5.getNextBlock(20)); // End of normal5124
-
-        assertEquals(POIFSConstants.END_OF_CHAIN, fs5.getNextBlock(21)); // Mini Stream FAT
-        assertEquals(POIFSConstants.END_OF_CHAIN, fs5.getNextBlock(22)); // Mini Stream data
-        assertEquals(POIFSConstants.END_OF_CHAIN, fs5.getNextBlock(23)); // Properties #2
-        assertEquals(POIFSConstants.UNUSED_BLOCK, fs5.getNextBlock(24));
-
-
-        // Check some data
-        assertEquals(1, fs5.getRoot().getEntryCount());
-        testDir = (DirectoryEntry) fs5.getRoot().getEntry("Test Directory");
-        assertEquals(3, testDir.getEntryCount());
-
-        miniDoc = (DocumentEntry) testDir.getEntry("Mini");
-        assertContentsMatches(mini, miniDoc);
-
-        normDoc = (DocumentEntry) testDir.getEntry("Normal4096");
-        assertContentsMatches(main4096, normDoc);
-
-        normDoc = (DocumentEntry) testDir.getEntry("Normal5124");
-        assertContentsMatches(main5124, normDoc);
-
-
-        // Delete a couple of streams
-        miniDoc.delete();
-        normDoc.delete();
-
-
-        // Check - will have un-used sectors now
-        POIFSFileSystem fs6 = writeOutAndReadBack(fs5);
-        fs5.close();
-
-        assertEquals(POIFSConstants.END_OF_CHAIN, fs6.getNextBlock(0)); // Props back in 1 block
-        assertEquals(POIFSConstants.FAT_SECTOR_BLOCK, fs6.getNextBlock(1));
-
-        assertEquals(3, fs6.getNextBlock(2));
-        assertEquals(4, fs6.getNextBlock(3));
-        assertEquals(5, fs6.getNextBlock(4));
-        assertEquals(6, fs6.getNextBlock(5));
-        assertEquals(7, fs6.getNextBlock(6));
-        assertEquals(8, fs6.getNextBlock(7));
-        assertEquals(9, fs6.getNextBlock(8));
-        assertEquals(POIFSConstants.END_OF_CHAIN, fs6.getNextBlock(9)); // End of normal4096
-
-        assertEquals(POIFSConstants.UNUSED_BLOCK, fs6.getNextBlock(10));
-        assertEquals(POIFSConstants.UNUSED_BLOCK, fs6.getNextBlock(11));
-        assertEquals(POIFSConstants.UNUSED_BLOCK, fs6.getNextBlock(12));
-        assertEquals(POIFSConstants.UNUSED_BLOCK, fs6.getNextBlock(13));
-        assertEquals(POIFSConstants.UNUSED_BLOCK, fs6.getNextBlock(14));
-        assertEquals(POIFSConstants.UNUSED_BLOCK, fs6.getNextBlock(15));
-        assertEquals(POIFSConstants.UNUSED_BLOCK, fs6.getNextBlock(16));
-        assertEquals(POIFSConstants.UNUSED_BLOCK, fs6.getNextBlock(17));
-        assertEquals(POIFSConstants.UNUSED_BLOCK, fs6.getNextBlock(18));
-        assertEquals(POIFSConstants.UNUSED_BLOCK, fs6.getNextBlock(19));
-        assertEquals(POIFSConstants.UNUSED_BLOCK, fs6.getNextBlock(20));
-
-        assertEquals(POIFSConstants.END_OF_CHAIN, fs6.getNextBlock(21)); // Mini Stream FAT
-        assertEquals(POIFSConstants.END_OF_CHAIN, fs6.getNextBlock(22)); // Mini Stream data
-        assertEquals(POIFSConstants.UNUSED_BLOCK, fs6.getNextBlock(23)); // Properties gone
-        assertEquals(POIFSConstants.UNUSED_BLOCK, fs6.getNextBlock(24));
-        assertEquals(POIFSConstants.UNUSED_BLOCK, fs6.getNextBlock(25));
-
-        // All done
-        fs6.close();
-    }
+        try (POIFSFileSystem fs3 = new POIFSFileSystem();
+            POIFSFileSystem fs4 = writeOutFileAndReadBack(fs3)) {
 
-    @Test
-    void addBeforeWrite() throws IOException {
-        POIFSFileSystem fs1 = new POIFSFileSystem();
-        DocumentEntry miniDoc;
-        DocumentEntry normDoc;
-        HeaderBlock hdr;
-
-        // Initially has Properties + BAT but nothing else
-        assertEquals(POIFSConstants.END_OF_CHAIN, fs1.getNextBlock(0));
-        assertEquals(POIFSConstants.FAT_SECTOR_BLOCK, fs1.getNextBlock(1));
-        assertEquals(POIFSConstants.UNUSED_BLOCK, fs1.getNextBlock(2));
-
-        hdr = writeOutAndReadHeader(fs1);
-        // No mini stream, and no xbats
-        // Will have fat then properties stream
-        assertEquals(1, hdr.getBATCount());
-        assertEquals(1, hdr.getBATArray()[0]);
-        assertEquals(0, hdr.getPropertyStart());
-        assertEquals(POIFSConstants.END_OF_CHAIN, hdr.getSBATStart());
-        assertEquals(POIFSConstants.END_OF_CHAIN, hdr.getXBATIndex());
-        assertEquals(POIFSConstants.SMALLER_BIG_BLOCK_SIZE * 3, fs1.size());
-        fs1.close();
+            // Same, no change, SBAT remains empty
+            assertEquals(POIFSConstants.END_OF_CHAIN, fs4.getNextBlock(0));
+            assertEquals(POIFSConstants.FAT_SECTOR_BLOCK, fs4.getNextBlock(1));
+            assertEquals(POIFSConstants.UNUSED_BLOCK, fs4.getNextBlock(2));
+            assertEquals(POIFSConstants.UNUSED_BLOCK, fs4.getNextBlock(3));
+            assertEquals(POIFSConstants.END_OF_CHAIN, fs4.getRoot().getProperty().getStartBlock());
+            assertEquals(0, fs4._get_property_table().getStartBlock());
 
-        // Get a clean filesystem to start with
-        fs1 = new POIFSFileSystem();
-
-        // Put our test files in a non-standard place
-        DirectoryEntry parentDir = fs1.createDirectory("Parent Directory");
-        DirectoryEntry testDir = parentDir.createDirectory("Test Directory");
-
-
-        // Add to the mini stream
-        byte[] mini = new byte[]{42, 0, 1, 2, 3, 4, 42};
-        testDir.createDocument("Mini", new ByteArrayInputStream(mini));
-
-        // Add to the main stream
-        byte[] main4096 = new byte[4096];
-        main4096[0] = -10;
-        main4096[4095] = -11;
-        testDir.createDocument("Normal4096", new ByteArrayInputStream(main4096));
-
-
-        // Check the mini stream was added, then the main stream
-        assertEquals(POIFSConstants.END_OF_CHAIN, fs1.getNextBlock(0));
-        assertEquals(POIFSConstants.FAT_SECTOR_BLOCK, fs1.getNextBlock(1));
-        assertEquals(POIFSConstants.END_OF_CHAIN, fs1.getNextBlock(2)); // Mini Fat
-        assertEquals(POIFSConstants.END_OF_CHAIN, fs1.getNextBlock(3)); // Mini Stream
-        assertEquals(5, fs1.getNextBlock(4)); // Main Stream
-        assertEquals(6, fs1.getNextBlock(5));
-        assertEquals(7, fs1.getNextBlock(6));
-        assertEquals(8, fs1.getNextBlock(7));
-        assertEquals(9, fs1.getNextBlock(8));
-        assertEquals(10, fs1.getNextBlock(9));
-        assertEquals(11, fs1.getNextBlock(10));
-        assertEquals(POIFSConstants.END_OF_CHAIN, fs1.getNextBlock(11));
-        assertEquals(POIFSConstants.UNUSED_BLOCK, fs1.getNextBlock(12));
-        assertEquals(POIFSConstants.SMALLER_BIG_BLOCK_SIZE * 13, fs1.size());
 
+            // Put everything within a new directory
+            DirectoryEntry testDir = fs4.createDirectory("Test Directory");
 
-        // Check that we can read the right data pre-write
-        miniDoc = (DocumentEntry) testDir.getEntry("Mini");
-        assertContentsMatches(mini, miniDoc);
-
-        normDoc = (DocumentEntry) testDir.getEntry("Normal4096");
-        assertContentsMatches(main4096, normDoc);
-
-
-        // Write, read, check
-        hdr = writeOutAndReadHeader(fs1);
-        POIFSFileSystem fs2 = writeOutAndReadBack(fs1);
-        fs1.close();
-
-        // Check the header details - will have the sbat near the start,
-        //  then the properties at the end
-        assertEquals(1, hdr.getBATCount());
-        assertEquals(1, hdr.getBATArray()[0]);
-        assertEquals(2, hdr.getSBATStart());
-        assertEquals(0, hdr.getPropertyStart());
-        assertEquals(POIFSConstants.END_OF_CHAIN, hdr.getXBATIndex());
-
-        // Check the block allocation is unchanged, other than
-        //  the properties stream going in at the end
-        assertEquals(12, fs2.getNextBlock(0)); // Properties
-        assertEquals(POIFSConstants.FAT_SECTOR_BLOCK, fs2.getNextBlock(1));
-        assertEquals(POIFSConstants.END_OF_CHAIN, fs2.getNextBlock(2));
-        assertEquals(POIFSConstants.END_OF_CHAIN, fs2.getNextBlock(3));
-        assertEquals(5, fs2.getNextBlock(4));
-        assertEquals(6, fs2.getNextBlock(5));
-        assertEquals(7, fs2.getNextBlock(6));
-        assertEquals(8, fs2.getNextBlock(7));
-        assertEquals(9, fs2.getNextBlock(8));
-        assertEquals(10, fs2.getNextBlock(9));
-        assertEquals(11, fs2.getNextBlock(10));
-        assertEquals(POIFSConstants.END_OF_CHAIN, fs2.getNextBlock(11));
-        assertEquals(POIFSConstants.END_OF_CHAIN, fs2.getNextBlock(12));
-        assertEquals(POIFSConstants.UNUSED_BLOCK, fs2.getNextBlock(13));
-        assertEquals(POIFSConstants.SMALLER_BIG_BLOCK_SIZE * 14, fs2.size());
+            // Add a new Normal Stream (Normal Streams minimum 4096 bytes)
+            byte[] main4096 = new byte[4096];
+            main4096[0] = -10;
+            main4096[4095] = -11;
+            testDir.createDocument("Normal4096", new ByteArrayInputStream(main4096));
 
+            assertEquals(POIFSConstants.END_OF_CHAIN, fs4.getNextBlock(0));
+            assertEquals(POIFSConstants.FAT_SECTOR_BLOCK, fs4.getNextBlock(1));
+            assertEquals(3, fs4.getNextBlock(2));
+            assertEquals(4, fs4.getNextBlock(3));
+            assertEquals(5, fs4.getNextBlock(4));
+            assertEquals(6, fs4.getNextBlock(5));
+            assertEquals(7, fs4.getNextBlock(6));
+            assertEquals(8, fs4.getNextBlock(7));
+            assertEquals(9, fs4.getNextBlock(8));
+            assertEquals(POIFSConstants.END_OF_CHAIN, fs4.getNextBlock(9));
+            assertEquals(POIFSConstants.UNUSED_BLOCK, fs4.getNextBlock(10));
+            assertEquals(POIFSConstants.UNUSED_BLOCK, fs4.getNextBlock(11));
+            // SBAT still unused
+            assertEquals(POIFSConstants.END_OF_CHAIN, fs4.getRoot().getProperty().getStartBlock());
+
+
+            // Add a bigger Normal Stream
+            byte[] main5124 = new byte[5124];
+            main5124[0] = -22;
+            main5124[5123] = -33;
+            testDir.createDocument("Normal5124", new ByteArrayInputStream(main5124));
+
+            assertEquals(POIFSConstants.END_OF_CHAIN, fs4.getNextBlock(0));
+            assertEquals(POIFSConstants.FAT_SECTOR_BLOCK, fs4.getNextBlock(1));
+            assertEquals(3, fs4.getNextBlock(2));
+            assertEquals(4, fs4.getNextBlock(3));
+            assertEquals(5, fs4.getNextBlock(4));
+            assertEquals(6, fs4.getNextBlock(5));
+            assertEquals(7, fs4.getNextBlock(6));
+            assertEquals(8, fs4.getNextBlock(7));
+            assertEquals(9, fs4.getNextBlock(8));
+            assertEquals(POIFSConstants.END_OF_CHAIN, fs4.getNextBlock(9));
+
+            assertEquals(11, fs4.getNextBlock(10));
+            assertEquals(12, fs4.getNextBlock(11));
+            assertEquals(13, fs4.getNextBlock(12));
+            assertEquals(14, fs4.getNextBlock(13));
+            assertEquals(15, fs4.getNextBlock(14));
+            assertEquals(16, fs4.getNextBlock(15));
+            assertEquals(17, fs4.getNextBlock(16));
+            assertEquals(18, fs4.getNextBlock(17));
+            assertEquals(19, fs4.getNextBlock(18));
+            assertEquals(20, fs4.getNextBlock(19));
+            assertEquals(POIFSConstants.END_OF_CHAIN, fs4.getNextBlock(20));
+            assertEquals(POIFSConstants.UNUSED_BLOCK, fs4.getNextBlock(21));
+            assertEquals(POIFSConstants.UNUSED_BLOCK, fs4.getNextBlock(22));
+
+            assertEquals(POIFSConstants.END_OF_CHAIN, fs4.getRoot().getProperty().getStartBlock());
+
+
+            // Now Add a mini stream
+            byte[] mini = new byte[]{42, 0, 1, 2, 3, 4, 42};
+            testDir.createDocument("Mini", new ByteArrayInputStream(mini));
 
-        // Check the data
-        DirectoryEntry fsRoot = fs2.getRoot();
-        assertEquals(1, fsRoot.getEntryCount());
+            // Mini stream will get one block for fat + one block for data
+            assertEquals(POIFSConstants.END_OF_CHAIN, fs4.getNextBlock(0));
+            assertEquals(POIFSConstants.FAT_SECTOR_BLOCK, fs4.getNextBlock(1));
+            assertEquals(3, fs4.getNextBlock(2));
+            assertEquals(4, fs4.getNextBlock(3));
+            assertEquals(5, fs4.getNextBlock(4));
+            assertEquals(6, fs4.getNextBlock(5));
+            assertEquals(7, fs4.getNextBlock(6));
+            assertEquals(8, fs4.getNextBlock(7));
+            assertEquals(9, fs4.getNextBlock(8));
+            assertEquals(POIFSConstants.END_OF_CHAIN, fs4.getNextBlock(9));
+
+            assertEquals(11, fs4.getNextBlock(10));
+            assertEquals(12, fs4.getNextBlock(11));
+            assertEquals(13, fs4.getNextBlock(12));
+            assertEquals(14, fs4.getNextBlock(13));
+            assertEquals(15, fs4.getNextBlock(14));
+            assertEquals(16, fs4.getNextBlock(15));
+            assertEquals(17, fs4.getNextBlock(16));
+            assertEquals(18, fs4.getNextBlock(17));
+            assertEquals(19, fs4.getNextBlock(18));
+            assertEquals(20, fs4.getNextBlock(19));
+            assertEquals(POIFSConstants.END_OF_CHAIN, fs4.getNextBlock(20));
+            assertEquals(POIFSConstants.END_OF_CHAIN, fs4.getNextBlock(21));
+            assertEquals(POIFSConstants.END_OF_CHAIN, fs4.getNextBlock(22));
+            assertEquals(POIFSConstants.UNUSED_BLOCK, fs4.getNextBlock(23));
+
+            // Check the mini stream location was set
+            // (21 is mini fat, 22 is first mini stream block)
+            assertEquals(22, fs4.getRoot().getProperty().getStartBlock());
+
+
+            // Write and read back
+            try (POIFSFileSystem fs5 = writeOutAndReadBack(fs4)) {
+                HeaderBlock header = writeOutAndReadHeader(fs5);
+
+                // Check the header has the right points in it
+                assertEquals(1, header.getBATCount());
+                assertEquals(1, header.getBATArray()[0]);
+                assertEquals(0, header.getPropertyStart());
+                assertEquals(1, header.getSBATCount());
+                assertEquals(21, header.getSBATStart());
+                assertEquals(22, fs5._get_property_table().getRoot().getStartBlock());
+
+                // Block use should be almost the same, except the properties
+                //  stream will have grown out to cover 2 blocks
+                // Check the block use is all unchanged
+                assertEquals(23, fs5.getNextBlock(0)); // Properties now extends over 2 blocks
+                assertEquals(POIFSConstants.FAT_SECTOR_BLOCK, fs5.getNextBlock(1));
+
+                assertEquals(3, fs5.getNextBlock(2));
+                assertEquals(4, fs5.getNextBlock(3));
+                assertEquals(5, fs5.getNextBlock(4));
+                assertEquals(6, fs5.getNextBlock(5));
+                assertEquals(7, fs5.getNextBlock(6));
+                assertEquals(8, fs5.getNextBlock(7));
+                assertEquals(9, fs5.getNextBlock(8));
+                assertEquals(POIFSConstants.END_OF_CHAIN, fs5.getNextBlock(9)); // End of normal4096
+
+                assertEquals(11, fs5.getNextBlock(10));
+                assertEquals(12, fs5.getNextBlock(11));
+                assertEquals(13, fs5.getNextBlock(12));
+                assertEquals(14, fs5.getNextBlock(13));
+                assertEquals(15, fs5.getNextBlock(14));
+                assertEquals(16, fs5.getNextBlock(15));
+                assertEquals(17, fs5.getNextBlock(16));
+                assertEquals(18, fs5.getNextBlock(17));
+                assertEquals(19, fs5.getNextBlock(18));
+                assertEquals(20, fs5.getNextBlock(19));
+                assertEquals(POIFSConstants.END_OF_CHAIN, fs5.getNextBlock(20)); // End of normal5124
+
+                assertEquals(POIFSConstants.END_OF_CHAIN, fs5.getNextBlock(21)); // Mini Stream FAT
+                assertEquals(POIFSConstants.END_OF_CHAIN, fs5.getNextBlock(22)); // Mini Stream data
+                assertEquals(POIFSConstants.END_OF_CHAIN, fs5.getNextBlock(23)); // Properties #2
+                assertEquals(POIFSConstants.UNUSED_BLOCK, fs5.getNextBlock(24));
+
+
+                // Check some data
+                assertEquals(1, fs5.getRoot().getEntryCount());
+                testDir = (DirectoryEntry) fs5.getRoot().getEntry("Test Directory");
+                assertEquals(3, testDir.getEntryCount());
+
+                DocumentEntry miniDoc = (DocumentEntry) testDir.getEntry("Mini");
+                assertContentsMatches(mini, miniDoc);
+
+                DocumentEntry normDoc = (DocumentEntry) testDir.getEntry("Normal4096");
+                assertContentsMatches(main4096, normDoc);
+
+                normDoc = (DocumentEntry) testDir.getEntry("Normal5124");
+                assertContentsMatches(main5124, normDoc);
+
+
+                // Delete a couple of streams
+                miniDoc.delete();
+                normDoc.delete();
+
+
+                // Check - will have un-used sectors now
+                try (POIFSFileSystem fs6 = writeOutAndReadBack(fs5)) {
+
+                    assertEquals(POIFSConstants.END_OF_CHAIN, fs6.getNextBlock(0)); // Props back in 1 block
+                    assertEquals(POIFSConstants.FAT_SECTOR_BLOCK, fs6.getNextBlock(1));
+
+                    assertEquals(3, fs6.getNextBlock(2));
+                    assertEquals(4, fs6.getNextBlock(3));
+                    assertEquals(5, fs6.getNextBlock(4));
+                    assertEquals(6, fs6.getNextBlock(5));
+                    assertEquals(7, fs6.getNextBlock(6));
+                    assertEquals(8, fs6.getNextBlock(7));
+                    assertEquals(9, fs6.getNextBlock(8));
+                    assertEquals(POIFSConstants.END_OF_CHAIN, fs6.getNextBlock(9)); // End of normal4096
+
+                    assertEquals(POIFSConstants.UNUSED_BLOCK, fs6.getNextBlock(10));
+                    assertEquals(POIFSConstants.UNUSED_BLOCK, fs6.getNextBlock(11));
+                    assertEquals(POIFSConstants.UNUSED_BLOCK, fs6.getNextBlock(12));
+                    assertEquals(POIFSConstants.UNUSED_BLOCK, fs6.getNextBlock(13));
+                    assertEquals(POIFSConstants.UNUSED_BLOCK, fs6.getNextBlock(14));
+                    assertEquals(POIFSConstants.UNUSED_BLOCK, fs6.getNextBlock(15));
+                    assertEquals(POIFSConstants.UNUSED_BLOCK, fs6.getNextBlock(16));
+                    assertEquals(POIFSConstants.UNUSED_BLOCK, fs6.getNextBlock(17));
+                    assertEquals(POIFSConstants.UNUSED_BLOCK, fs6.getNextBlock(18));
+                    assertEquals(POIFSConstants.UNUSED_BLOCK, fs6.getNextBlock(19));
+                    assertEquals(POIFSConstants.UNUSED_BLOCK, fs6.getNextBlock(20));
+
+                    assertEquals(POIFSConstants.END_OF_CHAIN, fs6.getNextBlock(21)); // Mini Stream FAT
+                    assertEquals(POIFSConstants.END_OF_CHAIN, fs6.getNextBlock(22)); // Mini Stream data
+                    assertEquals(POIFSConstants.UNUSED_BLOCK, fs6.getNextBlock(23)); // Properties gone
+                    assertEquals(POIFSConstants.UNUSED_BLOCK, fs6.getNextBlock(24));
+                    assertEquals(POIFSConstants.UNUSED_BLOCK, fs6.getNextBlock(25));
+                }
+            }
+        }
 
-        parentDir = (DirectoryEntry) fsRoot.getEntry("Parent Directory");
-        assertEquals(1, parentDir.getEntryCount());
+    }
 
-        testDir = (DirectoryEntry) parentDir.getEntry("Test Directory");
-        assertEquals(2, testDir.getEntryCount());
+    @Test
+    void addBeforeWrite() throws IOException {
+        try (POIFSFileSystem fs1 = new POIFSFileSystem()) {
+
+            // Initially has Properties + BAT but nothing else
+            assertEquals(POIFSConstants.END_OF_CHAIN, fs1.getNextBlock(0));
+            assertEquals(POIFSConstants.FAT_SECTOR_BLOCK, fs1.getNextBlock(1));
+            assertEquals(POIFSConstants.UNUSED_BLOCK, fs1.getNextBlock(2));
+
+            HeaderBlock hdr = writeOutAndReadHeader(fs1);
+            // No mini stream, and no xbats
+            // Will have fat then properties stream
+            assertEquals(1, hdr.getBATCount());
+            assertEquals(1, hdr.getBATArray()[0]);
+            assertEquals(0, hdr.getPropertyStart());
+            assertEquals(POIFSConstants.END_OF_CHAIN, hdr.getSBATStart());
+            assertEquals(POIFSConstants.END_OF_CHAIN, hdr.getXBATIndex());
+            assertEquals(POIFSConstants.SMALLER_BIG_BLOCK_SIZE * 3, fs1.size());
+        }
 
-        miniDoc = (DocumentEntry) testDir.getEntry("Mini");
-        assertContentsMatches(mini, miniDoc);
+        // Get a clean filesystem to start with
+        try (POIFSFileSystem fs1 = new POIFSFileSystem()) {
 
-        normDoc = (DocumentEntry) testDir.getEntry("Normal4096");
-        assertContentsMatches(main4096, normDoc);
+            // Put our test files in a non-standard place
+            DirectoryEntry parentDir = fs1.createDirectory("Parent Directory");
+            DirectoryEntry testDir = parentDir.createDirectory("Test Directory");
 
 
-        // Add one more stream to each, then save and re-load
-        byte[] mini2 = new byte[]{-42, 0, -1, -2, -3, -4, -42};
-        testDir.createDocument("Mini2", new ByteArrayInputStream(mini2));
+            // Add to the mini stream
+            byte[] mini = new byte[]{42, 0, 1, 2, 3, 4, 42};
+            testDir.createDocument("Mini", new ByteArrayInputStream(mini));
 
-        // Add to the main stream
-        byte[] main4106 = new byte[4106];
-        main4106[0] = 41;
-        main4106[4105] = 42;
-        testDir.createDocument("Normal4106", new ByteArrayInputStream(main4106));
+            // Add to the main stream
+            byte[] main4096 = new byte[4096];
+            main4096[0] = -10;
+            main4096[4095] = -11;
+            testDir.createDocument("Normal4096", new ByteArrayInputStream(main4096));
 
 
-        // Recheck the data in all 4 streams
-        POIFSFileSystem fs3 = writeOutAndReadBack(fs2);
-        fs2.close();
-
-        fsRoot = fs3.getRoot();
-        assertEquals(1, fsRoot.getEntryCount());
-
-        parentDir = (DirectoryEntry) fsRoot.getEntry("Parent Directory");
-        assertEquals(1, parentDir.getEntryCount());
-
-        testDir = (DirectoryEntry) parentDir.getEntry("Test Directory");
-        assertEquals(4, testDir.getEntryCount());
-
-        miniDoc = (DocumentEntry) testDir.getEntry("Mini");
-        assertContentsMatches(mini, miniDoc);
-
-        miniDoc = (DocumentEntry) testDir.getEntry("Mini2");
-        assertContentsMatches(mini2, miniDoc);
-
-        normDoc = (DocumentEntry) testDir.getEntry("Normal4106");
-        assertContentsMatches(main4106, normDoc);
-
-        // All done
-        fs3.close();
+            // Check the mini stream was added, then the main stream
+            assertEquals(POIFSConstants.END_OF_CHAIN, fs1.getNextBlock(0));
+            assertEquals(POIFSConstants.FAT_SECTOR_BLOCK, fs1.getNextBlock(1));
+            assertEquals(POIFSConstants.END_OF_CHAIN, fs1.getNextBlock(2)); // Mini Fat
+            assertEquals(POIFSConstants.END_OF_CHAIN, fs1.getNextBlock(3)); // Mini Stream
+            assertEquals(5, fs1.getNextBlock(4)); // Main Stream
+            assertEquals(6, fs1.getNextBlock(5));
+            assertEquals(7, fs1.getNextBlock(6));
+            assertEquals(8, fs1.getNextBlock(7));
+            assertEquals(9, fs1.getNextBlock(8));
+            assertEquals(10, fs1.getNextBlock(9));
+            assertEquals(11, fs1.getNextBlock(10));
+            assertEquals(POIFSConstants.END_OF_CHAIN, fs1.getNextBlock(11));
+            assertEquals(POIFSConstants.UNUSED_BLOCK, fs1.getNextBlock(12));
+            assertEquals(POIFSConstants.SMALLER_BIG_BLOCK_SIZE * 13, fs1.size());
+
+
+            // Check that we can read the right data pre-write
+            DocumentEntry miniDoc = (DocumentEntry) testDir.getEntry("Mini");
+            assertContentsMatches(mini, miniDoc);
+
+            DocumentEntry normDoc = (DocumentEntry) testDir.getEntry("Normal4096");
+            assertContentsMatches(main4096, normDoc);
+
+
+            // Write, read, check
+            HeaderBlock hdr = writeOutAndReadHeader(fs1);
+            try (POIFSFileSystem fs2 = writeOutAndReadBack(fs1)) {
+                // Check the header details - will have the sbat near the start,
+                //  then the properties at the end
+                assertEquals(1, hdr.getBATCount());
+                assertEquals(1, hdr.getBATArray()[0]);
+                assertEquals(2, hdr.getSBATStart());
+                assertEquals(0, hdr.getPropertyStart());
+                assertEquals(POIFSConstants.END_OF_CHAIN, hdr.getXBATIndex());
+
+                // Check the block allocation is unchanged, other than
+                //  the properties stream going in at the end
+                assertEquals(12, fs2.getNextBlock(0)); // Properties
+                assertEquals(POIFSConstants.FAT_SECTOR_BLOCK, fs2.getNextBlock(1));
+                assertEquals(POIFSConstants.END_OF_CHAIN, fs2.getNextBlock(2));
+                assertEquals(POIFSConstants.END_OF_CHAIN, fs2.getNextBlock(3));
+                assertEquals(5, fs2.getNextBlock(4));
+                assertEquals(6, fs2.getNextBlock(5));
+                assertEquals(7, fs2.getNextBlock(6));
+                assertEquals(8, fs2.getNextBlock(7));
+                assertEquals(9, fs2.getNextBlock(8));
+                assertEquals(10, fs2.getNextBlock(9));
+                assertEquals(11, fs2.getNextBlock(10));
+                assertEquals(POIFSConstants.END_OF_CHAIN, fs2.getNextBlock(11));
+                assertEquals(POIFSConstants.END_OF_CHAIN, fs2.getNextBlock(12));
+                assertEquals(POIFSConstants.UNUSED_BLOCK, fs2.getNextBlock(13));
+                assertEquals(POIFSConstants.SMALLER_BIG_BLOCK_SIZE * 14, fs2.size());
+
+
+                // Check the data
+                DirectoryEntry fsRoot = fs2.getRoot();
+                assertEquals(1, fsRoot.getEntryCount());
+
+                parentDir = (DirectoryEntry) fsRoot.getEntry("Parent Directory");
+                assertEquals(1, parentDir.getEntryCount());
+
+                testDir = (DirectoryEntry) parentDir.getEntry("Test Directory");
+                assertEquals(2, testDir.getEntryCount());
+
+                miniDoc = (DocumentEntry) testDir.getEntry("Mini");
+                assertContentsMatches(mini, miniDoc);
+
+                normDoc = (DocumentEntry) testDir.getEntry("Normal4096");
+                assertContentsMatches(main4096, normDoc);
+
+
+                // Add one more stream to each, then save and re-load
+                byte[] mini2 = new byte[]{-42, 0, -1, -2, -3, -4, -42};
+                testDir.createDocument("Mini2", new ByteArrayInputStream(mini2));
+
+                // Add to the main stream
+                byte[] main4106 = new byte[4106];
+                main4106[0] = 41;
+                main4106[4105] = 42;
+                testDir.createDocument("Normal4106", new ByteArrayInputStream(main4106));
+
+                // Recheck the data in all 4 streams
+                try (POIFSFileSystem fs3 = writeOutAndReadBack(fs2)) {
+                    fsRoot = fs3.getRoot();
+                    assertEquals(1, fsRoot.getEntryCount());
+
+                    parentDir = (DirectoryEntry) fsRoot.getEntry("Parent Directory");
+                    assertEquals(1, parentDir.getEntryCount());
+
+                    testDir = (DirectoryEntry) parentDir.getEntry("Test Directory");
+                    assertEquals(4, testDir.getEntryCount());
+
+                    miniDoc = (DocumentEntry) testDir.getEntry("Mini");
+                    assertContentsMatches(mini, miniDoc);
+
+                    miniDoc = (DocumentEntry) testDir.getEntry("Mini2");
+                    assertContentsMatches(mini2, miniDoc);
+
+                    normDoc = (DocumentEntry) testDir.getEntry("Normal4106");
+                    assertContentsMatches(main4106, normDoc);
+                }
+            }
+        }
     }
 
     @Test
     void readZeroLengthEntries() throws IOException {
-        POIFSFileSystem fs = new POIFSFileSystem(_inst.getFile("only-zero-byte-streams.ole2"));
-        DirectoryNode testDir = fs.getRoot();
-        assertEquals(3, testDir.getEntryCount());
-        DocumentEntry entry;
+        try (POIFSFileSystem fs = new POIFSFileSystem(_inst.getFile("only-zero-byte-streams.ole2"))) {
+            DirectoryNode testDir = fs.getRoot();
+            assertEquals(3, testDir.getEntryCount());
 
-        entry = (DocumentEntry) testDir.getEntry("test-zero-1");
-        assertNotNull(entry);
-        assertEquals(0, entry.getSize());
+            DocumentEntry entry = (DocumentEntry) testDir.getEntry("test-zero-1");
+            assertNotNull(entry);
+            assertEquals(0, entry.getSize());
 
-        entry = (DocumentEntry) testDir.getEntry("test-zero-2");
-        assertNotNull(entry);
-        assertEquals(0, entry.getSize());
+            entry = (DocumentEntry) testDir.getEntry("test-zero-2");
+            assertNotNull(entry);
+            assertEquals(0, entry.getSize());
 
-        entry = (DocumentEntry) testDir.getEntry("test-zero-3");
-        assertNotNull(entry);
-        assertEquals(0, entry.getSize());
+            entry = (DocumentEntry) testDir.getEntry("test-zero-3");
+            assertNotNull(entry);
+            assertEquals(0, entry.getSize());
 
-        // Check properties, all have zero length, no blocks
-        PropertyTable props = fs._get_property_table();
-        assertEquals(POIFSConstants.END_OF_CHAIN, props.getRoot().getStartBlock());
-        for (Property prop : props.getRoot()) {
-            assertEquals("test-zero-", prop.getName().substring(0, 10));
-            assertEquals(POIFSConstants.END_OF_CHAIN, prop.getStartBlock());
+            // Check properties, all have zero length, no blocks
+            PropertyTable props = fs._get_property_table();
+            assertEquals(POIFSConstants.END_OF_CHAIN, props.getRoot().getStartBlock());
+            for (Property prop : props.getRoot()) {
+                assertEquals("test-zero-", prop.getName().substring(0, 10));
+                assertEquals(POIFSConstants.END_OF_CHAIN, prop.getStartBlock());
+            }
         }
-
-        // All done
-        fs.close();
     }
 
     @Test
     void writeZeroLengthEntries() throws IOException {
-        POIFSFileSystem fs1 = new POIFSFileSystem();
-        DirectoryNode testDir = fs1.getRoot();
-        DocumentEntry miniDoc;
-        DocumentEntry normDoc;
-        DocumentEntry emptyDoc;
-
-        // Add mini and normal sized entries to start
-        byte[] mini2 = new byte[]{-42, 0, -1, -2, -3, -4, -42};
-        testDir.createDocument("Mini2", new ByteArrayInputStream(mini2));
+        try (POIFSFileSystem fs1 = new POIFSFileSystem()) {
+            DirectoryNode testDir = fs1.getRoot();
+            DocumentEntry miniDoc;
+            DocumentEntry normDoc;
+            DocumentEntry emptyDoc;
 
-        // Add to the main stream
-        byte[] main4106 = new byte[4106];
-        main4106[0] = 41;
-        main4106[4105] = 42;
-        testDir.createDocument("Normal4106", new ByteArrayInputStream(main4106));
+            // Add mini and normal sized entries to start
+            byte[] mini2 = new byte[]{-42, 0, -1, -2, -3, -4, -42};
+            testDir.createDocument("Mini2", new ByteArrayInputStream(mini2));
 
-        // Now add some empty ones
-        byte[] empty = new byte[0];
-        testDir.createDocument("empty-1", new ByteArrayInputStream(empty));
-        testDir.createDocument("empty-2", new ByteArrayInputStream(empty));
-        testDir.createDocument("empty-3", new ByteArrayInputStream(empty));
+            // Add to the main stream
+            byte[] main4106 = new byte[4106];
+            main4106[0] = 41;
+            main4106[4105] = 42;
+            testDir.createDocument("Normal4106", new ByteArrayInputStream(main4106));
 
-        // Check
-        miniDoc = (DocumentEntry) testDir.getEntry("Mini2");
-        assertContentsMatches(mini2, miniDoc);
+            // Now add some empty ones
+            byte[] empty = new byte[0];
+            testDir.createDocument("empty-1", new ByteArrayInputStream(empty));
+            testDir.createDocument("empty-2", new ByteArrayInputStream(empty));
+            testDir.createDocument("empty-3", new ByteArrayInputStream(empty));
 
-        normDoc = (DocumentEntry) testDir.getEntry("Normal4106");
-        assertContentsMatches(main4106, normDoc);
+            // Check
+            miniDoc = (DocumentEntry) testDir.getEntry("Mini2");
+            assertContentsMatches(mini2, miniDoc);
 
-        emptyDoc = (DocumentEntry) testDir.getEntry("empty-1");
-        assertContentsMatches(empty, emptyDoc);
+            normDoc = (DocumentEntry) testDir.getEntry("Normal4106");
+            assertContentsMatches(main4106, normDoc);
 
-        emptyDoc = (DocumentEntry) testDir.getEntry("empty-2");
-        assertContentsMatches(empty, emptyDoc);
+            emptyDoc = (DocumentEntry) testDir.getEntry("empty-1");
+            assertContentsMatches(empty, emptyDoc);
 
-        emptyDoc = (DocumentEntry) testDir.getEntry("empty-3");
-        assertContentsMatches(empty, emptyDoc);
+            emptyDoc = (DocumentEntry) testDir.getEntry("empty-2");
+            assertContentsMatches(empty, emptyDoc);
 
-        // Look at the properties entry, and check the empty ones
-        //  have zero size and no start block
-        PropertyTable props = fs1._get_property_table();
-        Iterator<Property> propsIt = props.getRoot().getChildren();
+            emptyDoc = (DocumentEntry) testDir.getEntry("empty-3");
+            assertContentsMatches(empty, emptyDoc);
 
-        Property prop = propsIt.next();
-        assertEquals("Mini2", prop.getName());
-        assertEquals(0, prop.getStartBlock());
-        assertEquals(7, prop.getSize());
+            // Look at the properties entry, and check the empty ones
+            //  have zero size and no start block
+            PropertyTable props = fs1._get_property_table();
+            Iterator<Property> propsIt = props.getRoot().getChildren();
 
-        prop = propsIt.next();
-        assertEquals("Normal4106", prop.getName());
-        assertEquals(4, prop.getStartBlock()); // BAT, Props, SBAT, MIni
-        assertEquals(4106, prop.getSize());
+            Property prop = propsIt.next();
+            assertEquals("Mini2", prop.getName());
+            assertEquals(0, prop.getStartBlock());
+            assertEquals(7, prop.getSize());
 
-        prop = propsIt.next();
-        assertEquals("empty-1", prop.getName());
-        assertEquals(POIFSConstants.END_OF_CHAIN, prop.getStartBlock());
-        assertEquals(0, prop.getSize());
+            prop = propsIt.next();
+            assertEquals("Normal4106", prop.getName());
+            assertEquals(4, prop.getStartBlock()); // BAT, Props, SBAT, MIni
+            assertEquals(4106, prop.getSize());
 
-        prop = propsIt.next();
-        assertEquals("empty-2", prop.getName());
-        assertEquals(POIFSConstants.END_OF_CHAIN, prop.getStartBlock());
-        assertEquals(0, prop.getSize());
+            prop = propsIt.next();
+            assertEquals("empty-1", prop.getName());
+            assertEquals(POIFSConstants.END_OF_CHAIN, prop.getStartBlock());
+            assertEquals(0, prop.getSize());
 
-        prop = propsIt.next();
-        assertEquals("empty-3", prop.getName());
-        assertEquals(POIFSConstants.END_OF_CHAIN, prop.getStartBlock());
-        assertEquals(0, prop.getSize());
+            prop = propsIt.next();
+            assertEquals("empty-2", prop.getName());
+            assertEquals(POIFSConstants.END_OF_CHAIN, prop.getStartBlock());
+            assertEquals(0, prop.getSize());
 
+            prop = propsIt.next();
+            assertEquals("empty-3", prop.getName());
+            assertEquals(POIFSConstants.END_OF_CHAIN, prop.getStartBlock());
+            assertEquals(0, prop.getSize());
 
-        // Save and re-check
-        POIFSFileSystem fs2 = writeOutAndReadBack(fs1);
-        fs1.close();
-        testDir = fs2.getRoot();
 
-        miniDoc = (DocumentEntry) testDir.getEntry("Mini2");
-        assertContentsMatches(mini2, miniDoc);
+            // Save and re-check
+            try (POIFSFileSystem fs2 = writeOutAndReadBack(fs1)) {
+                testDir = fs2.getRoot();
 
-        normDoc = (DocumentEntry) testDir.getEntry("Normal4106");
-        assertContentsMatches(main4106, normDoc);
+                miniDoc = (DocumentEntry) testDir.getEntry("Mini2");
+                assertContentsMatches(mini2, miniDoc);
 
-        emptyDoc = (DocumentEntry) testDir.getEntry("empty-1");
-        assertContentsMatches(empty, emptyDoc);
+                normDoc = (DocumentEntry) testDir.getEntry("Normal4106");
+                assertContentsMatches(main4106, normDoc);
 
-        emptyDoc = (DocumentEntry) testDir.getEntry("empty-2");
-        assertContentsMatches(empty, emptyDoc);
+                emptyDoc = (DocumentEntry) testDir.getEntry("empty-1");
+                assertContentsMatches(empty, emptyDoc);
 
-        emptyDoc = (DocumentEntry) testDir.getEntry("empty-3");
-        assertContentsMatches(empty, emptyDoc);
+                emptyDoc = (DocumentEntry) testDir.getEntry("empty-2");
+                assertContentsMatches(empty, emptyDoc);
 
-        // Check that a mini-stream was assigned, with one block used
-        assertEquals(3, testDir.getProperty().getStartBlock());
-        assertEquals(64, testDir.getProperty().getSize());
+                emptyDoc = (DocumentEntry) testDir.getEntry("empty-3");
+                assertContentsMatches(empty, emptyDoc);
 
-        // All done
-        fs2.close();
+                // Check that a mini-stream was assigned, with one block used
+                assertEquals(3, testDir.getProperty().getStartBlock());
+                assertEquals(64, testDir.getProperty().getSize());
+            }
+        }
     }
 
     /**
@@ -2527,22 +2498,16 @@ final class TestPOIFSStream {
     @Test
     void POIFSReadCopyWritePOIFSRead() throws IOException {
         File testFile = POIDataSamples.getSpreadSheetInstance().getFile("Simple.xls");
-        POIFSFileSystem src = new POIFSFileSystem(testFile);
-        byte[] wbDataExp = IOUtils.toByteArray(src.createDocumentInputStream("Workbook"));
-
-        POIFSFileSystem nfs = new POIFSFileSystem();
-        EntryUtils.copyNodes(src.getRoot(), nfs.getRoot());
-        src.close();
-
-        ByteArrayOutputStream bos = new ByteArrayOutputStream();
-        nfs.writeFilesystem(bos);
-        nfs.close();
-
-        POIFSFileSystem pfs = new POIFSFileSystem(new ByteArrayInputStream(bos.toByteArray()));
-        byte[] wbDataAct = IOUtils.toByteArray(pfs.createDocumentInputStream("Workbook"));
-
-        assertThat(wbDataExp, equalTo(wbDataAct));
-        pfs.close();
+        try (POIFSFileSystem src = new POIFSFileSystem(testFile);
+             POIFSFileSystem nfs = new POIFSFileSystem()) {
+            byte[] wbDataExp = IOUtils.toByteArray(src.createDocumentInputStream("Workbook"));
+            EntryUtils.copyNodes(src.getRoot(), nfs.getRoot());
+
+            try (POIFSFileSystem pfs = writeOutFileAndReadBack(nfs)) {
+                byte[] wbDataAct = IOUtils.toByteArray(pfs.createDocumentInputStream("Workbook"));
+                assertThat(wbDataExp, equalTo(wbDataAct));
+            }
+        }
     }
 
     /**
@@ -2552,31 +2517,28 @@ final class TestPOIFSStream {
     @Test
     void RecursiveDelete() throws IOException {
         File testFile = POIDataSamples.getSpreadSheetInstance().getFile("SimpleMacro.xls");
-        POIFSFileSystem src = new POIFSFileSystem(testFile);
-
-        // Starts out with 5 entries:
-        //  _VBA_PROJECT_CUR
-        //  SummaryInformation <(0x05)SummaryInformation>
-        //  DocumentSummaryInformation <(0x05)DocumentSummaryInformation>
-        //  Workbook
-        //  CompObj <(0x01)CompObj>
-        assertEquals(5, _countChildren(src._get_property_table().getRoot()));
-        assertEquals(5, src.getRoot().getEntryCount());
-
-        // Grab the VBA project root
-        DirectoryEntry vbaProj = (DirectoryEntry) src.getRoot().getEntry("_VBA_PROJECT_CUR");
-        assertEquals(3, vbaProj.getEntryCount());
-        // Can't delete yet, has stuff
-        assertFalse(vbaProj.delete());
-        // Recursively delete
-        _recursiveDeletee(vbaProj);
-
-        // Entries gone
-        assertEquals(4, _countChildren(src._get_property_table().getRoot()));
-        assertEquals(4, src.getRoot().getEntryCount());
-
-        // Done
-        src.close();
+        try (POIFSFileSystem src = new POIFSFileSystem(testFile)) {
+            // Starts out with 5 entries:
+            //  _VBA_PROJECT_CUR
+            //  SummaryInformation <(0x05)SummaryInformation>
+            //  DocumentSummaryInformation <(0x05)DocumentSummaryInformation>
+            //  Workbook
+            //  CompObj <(0x01)CompObj>
+            assertEquals(5, _countChildren(src._get_property_table().getRoot()));
+            assertEquals(5, src.getRoot().getEntryCount());
+
+            // Grab the VBA project root
+            DirectoryEntry vbaProj = (DirectoryEntry) src.getRoot().getEntry("_VBA_PROJECT_CUR");
+            assertEquals(3, vbaProj.getEntryCount());
+            // Can't delete yet, has stuff
+            assertFalse(vbaProj.delete());
+            // Recursively delete
+            _recursiveDeletee(vbaProj);
+
+            // Entries gone
+            assertEquals(4, _countChildren(src._get_property_table().getRoot()));
+            assertEquals(4, src.getRoot().getEntryCount());
+        }
     }
 
     private void _recursiveDeletee(Entry entry) throws IOException {
@@ -2628,82 +2590,80 @@ final class TestPOIFSStream {
         int s512mb = 512 * 1024 * 1024;
         long s2gb = 2L * 1024 * 1024 * 1024;
         DocumentEntry entry;
-        POIFSFileSystem fs;
 
         // Create a just-sub 2gb file
-        fs = POIFSFileSystem.create(big);
-        for (int i = 0; i < 19; i++) {
-            fs.createDocument(new DummyDataInputStream(s100mb), "Entry" + i);
+        try (POIFSFileSystem fs = POIFSFileSystem.create(big)) {
+            for (int i = 0; i < 19; i++) {
+                fs.createDocument(new DummyDataInputStream(s100mb), "Entry" + i);
+            }
+            fs.writeFilesystem();
         }
-        fs.writeFilesystem();
-        fs.close();
 
         // Extend it past the 2gb mark
-        fs = new POIFSFileSystem(big, false);
-        for (int i = 0; i < 19; i++) {
-            entry = (DocumentEntry) fs.getRoot().getEntry("Entry" + i);
-            assertNotNull(entry);
-            assertEquals(s100mb, entry.getSize());
-        }
+        try (POIFSFileSystem fs = new POIFSFileSystem(big, false)) {
+            for (int i = 0; i < 19; i++) {
+                entry = (DocumentEntry) fs.getRoot().getEntry("Entry" + i);
+                assertNotNull(entry);
+                assertEquals(s100mb, entry.getSize());
+            }
 
-        fs.createDocument(new DummyDataInputStream(s512mb), "Bigger");
-        fs.writeFilesystem();
-        fs.close();
+            fs.createDocument(new DummyDataInputStream(s512mb), "Bigger");
+            fs.writeFilesystem();
+        }
 
         // Check it still works
-        fs = new POIFSFileSystem(big, false);
-        for (int i = 0; i < 19; i++) {
-            entry = (DocumentEntry) fs.getRoot().getEntry("Entry" + i);
+        try (POIFSFileSystem fs = new POIFSFileSystem(big, false)) {
+            for (int i = 0; i < 19; i++) {
+                entry = (DocumentEntry) fs.getRoot().getEntry("Entry" + i);
+                assertNotNull(entry);
+                assertEquals(s100mb, entry.getSize());
+            }
+            entry = (DocumentEntry) fs.getRoot().getEntry("Bigger");
             assertNotNull(entry);
-            assertEquals(s100mb, entry.getSize());
+            assertEquals(s512mb, entry.getSize());
         }
-        entry = (DocumentEntry) fs.getRoot().getEntry("Bigger");
-        assertNotNull(entry);
-        assertEquals(s512mb, entry.getSize());
-
         // Tidy
-        fs.close();
         assertTrue(big.delete());
 
 
         // Create a >2gb file
-        fs = POIFSFileSystem.create(big);
-        for (int i = 0; i < 4; i++) {
-            fs.createDocument(new DummyDataInputStream(s512mb), "Entry" + i);
+        try (POIFSFileSystem fs = POIFSFileSystem.create(big)) {
+            for (int i = 0; i < 4; i++) {
+                fs.createDocument(new DummyDataInputStream(s512mb), "Entry" + i);
+            }
+            fs.writeFilesystem();
         }
-        fs.writeFilesystem();
-        fs.close();
 
         // Read it
-        fs = new POIFSFileSystem(big, false);
-        for (int i = 0; i < 4; i++) {
-            entry = (DocumentEntry) fs.getRoot().getEntry("Entry" + i);
-            assertNotNull(entry);
-            assertEquals(s512mb, entry.getSize());
-        }
+        try (POIFSFileSystem fs = new POIFSFileSystem(big, false)) {
+            for (int i = 0; i < 4; i++) {
+                entry = (DocumentEntry) fs.getRoot().getEntry("Entry" + i);
+                assertNotNull(entry);
+                assertEquals(s512mb, entry.getSize());
+            }
 
-        // Extend it
-        fs.createDocument(new DummyDataInputStream(s512mb), "Entry4");
-        fs.writeFilesystem();
-        fs.close();
+            // Extend it
+            fs.createDocument(new DummyDataInputStream(s512mb), "Entry4");
+            fs.writeFilesystem();
+        }
 
         // Check it worked
-        fs = new POIFSFileSystem(big, false);
-        for (int i = 0; i < 5; i++) {
-            entry = (DocumentEntry) fs.getRoot().getEntry("Entry" + i);
-            assertNotNull(entry);
-            assertEquals(s512mb, entry.getSize());
+        try (POIFSFileSystem fs = new POIFSFileSystem(big, false)) {
+            for (int i = 0; i < 5; i++) {
+                entry = (DocumentEntry) fs.getRoot().getEntry("Entry" + i);
+                assertNotNull(entry);
+                assertEquals(s512mb, entry.getSize());
+            }
         }
-
         // Tidy
-        fs.close();
         assertTrue(big.delete());
 
         // Create a file with a 2gb entry
-        fs = POIFSFileSystem.create(big);
-        fs.createDocument(new DummyDataInputStream(s100mb), "Small");
-        // TODO Check we get a helpful error about the max size
-        fs.createDocument(new DummyDataInputStream(s2gb), "Big");
+        try (POIFSFileSystem fs = POIFSFileSystem.create(big)) {
+            fs.createDocument(new DummyDataInputStream(s100mb), "Small");
+            // TODO Check we get a helpful error about the max size
+            fs.createDocument(new DummyDataInputStream(s2gb), "Big");
+        }
     }
 
     private static final class DummyDataInputStream extends InputStream {
@@ -2715,16 +2675,19 @@ final class TestPOIFSStream {
             this.size = 0;
         }
 
+        @Override
         public int read() {
             if (size >= maxSize) return -1;
             size++;
             return (int) (size % 128);
         }
 
+        @Override
         public int read(byte[] b) {
             return read(b, 0, b.length);
         }
 
+        @Override
         public int read(byte[] b, int offset, int len) {
             if (size >= maxSize) return -1;
             int sz = (int) Math.min(len, maxSize - size);
@@ -2741,7 +2704,6 @@ final class TestPOIFSStream {
     void performance() throws Exception {
         int iterations = 200;//1_000;
 
-        System.out.println("NPOI:");
         long start = System.currentTimeMillis();
 
         for (int i = 0; i < iterations; i++) {
@@ -2762,11 +2724,7 @@ final class TestPOIFSStream {
             }
         }
 
-        System.out.println();
         System.out.println("NPOI took: " + (System.currentTimeMillis() - start));
-
-        System.out.println();
-        System.out.println();
     }
 
     private static void copyAllEntries(DirectoryEntry srcDirectory, DirectoryEntry destDirectory) throws IOException {
@@ -2788,5 +2746,4 @@ final class TestPOIFSStream {
             }
         }
     }
-
 }
diff --git a/poi/src/test/java/org/apache/poi/poifs/filesystem/TestPropertySorter.java b/poi/src/test/java/org/apache/poi/poifs/filesystem/TestPropertySorter.java
index 29ed3001f0..25e9031828 100644
--- a/poi/src/test/java/org/apache/poi/poifs/filesystem/TestPropertySorter.java
+++ b/poi/src/test/java/org/apache/poi/poifs/filesystem/TestPropertySorter.java
@@ -17,17 +17,15 @@
 
 package org.apache.poi.poifs.filesystem;
 
+import static org.apache.poi.POIDataSamples.writeOutAndReadBack;
 import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotEquals;
 
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.util.ArrayList;
 import java.util.Arrays;
-import java.util.Iterator;
 import java.util.List;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
@@ -38,7 +36,7 @@ import org.apache.poi.poifs.property.Property;
 import org.junit.jupiter.api.Test;
 
 /**
- * Verify the order of entries <code>DirectoryProperty</code> .
+ * Verify the order of entries {@code DirectoryProperty} .
  * <p>
  * In particular it is important to serialize ROOT._VBA_PROJECT_CUR.VBA node.
  * See bug 39234 in bugzilla. Thanks to Bill Seddon for providing the solution.
@@ -63,28 +61,29 @@ final class TestPropertySorter {
     }
 
     /**
-     * Test sorting of properties in <code>DirectoryProperty</code>
+     * Test sorting of properties in {@code DirectoryProperty}
      */
     @Test
     void testSortProperties() throws IOException {
-        POIFSFileSystem fs = openSampleFS();
-        Property[] props = getVBAProperties(fs);
+        try (POIFSFileSystem fs = openSampleFS()) {
+            Property[] props = getVBAProperties(fs);
 
-        assertEquals(_entries.length, props.length);
+            assertEquals(_entries.length, props.length);
 
-        // (1). See that there is a problem with the old case-sensitive property comparator
-        Arrays.sort(props, TestPropertySorter::oldCaseSensitivePropertyCompareTo);
+            // (1). See that there is a problem with the old case-sensitive property comparator
+            Arrays.sort(props, TestPropertySorter::oldCaseSensitivePropertyCompareTo);
 
-        String exp = String.join("", _entries);
-        String actOld = Stream.of(props).map(Property::getName).collect(Collectors.joining());
+            String exp = String.join("", _entries);
+            String actOld = Stream.of(props).map(Property::getName).collect(Collectors.joining());
 
-        assertNotEquals("expected old case-sensitive property comparator to return properties in wrong order", exp, actOld);
+            assertNotEquals("expected old case-sensitive property comparator to return properties in wrong order", exp, actOld);
 
-        // (2) Verify that the fixed property comparator works right
-        Arrays.sort(props, new DirectoryProperty.PropertyComparator());
-        String[] actNew = Stream.of(props).map(Property::getName).toArray(String[]::new);
+            // (2) Verify that the fixed property comparator works right
+            Arrays.sort(props, new DirectoryProperty.PropertyComparator());
+            String[] actNew = Stream.of(props).map(Property::getName).toArray(String[]::new);
 
-        assertArrayEquals(_entries, actNew);
+            assertArrayEquals(_entries, actNew);
+        }
     }
 
     private static int oldCaseSensitivePropertyCompareTo(Property o1, Property o2) {
@@ -99,19 +98,14 @@ final class TestPropertySorter {
      */
     @Test
     void testSerialization() throws IOException {
-        POIFSFileSystem fs = openSampleFS();
-
-        ByteArrayOutputStream out = new ByteArrayOutputStream();
-        fs.writeFilesystem(out);
-        out.close();
-        InputStream is = new ByteArrayInputStream(out.toByteArray());
-        fs = new POIFSFileSystem(is);
-        is.close();
-        Property[] props = getVBAProperties(fs);
-        Arrays.sort(props, new DirectoryProperty.PropertyComparator());
-
-        String[] act = Stream.of(props).map(Property::getName).toArray(String[]::new);
-        assertArrayEquals(_entries, act);
+        try (POIFSFileSystem fs = openSampleFS();
+             POIFSFileSystem fs2 = writeOutAndReadBack(fs)) {
+            Property[] props = getVBAProperties(fs2);
+            Arrays.sort(props, new DirectoryProperty.PropertyComparator());
+
+            String[] act = Stream.of(props).map(Property::getName).toArray(String[]::new);
+            assertArrayEquals(_entries, act);
+        }
     }
 
     /**
@@ -128,10 +122,9 @@ final class TestPropertySorter {
         DirectoryProperty  p = (DirectoryProperty)vba.getProperty();
 
         List<Property> lst = new ArrayList<>();
-        for (Iterator<Property> it = p.getChildren(); it.hasNext();){
-            Property ch = it.next();
+        for (Property ch : p){
             lst.add(ch);
         }
-        return lst.toArray(new Property[ 0 ]);
+        return lst.toArray(new Property[0]);
     }
 }
diff --git a/poi/src/test/java/org/apache/poi/poifs/property/TestDirectoryProperty.java b/poi/src/test/java/org/apache/poi/poifs/property/TestDirectoryProperty.java
index 49b6553012..f3f855fd8d 100644
--- a/poi/src/test/java/org/apache/poi/poifs/property/TestDirectoryProperty.java
+++ b/poi/src/test/java/org/apache/poi/poifs/property/TestDirectoryProperty.java
@@ -22,13 +22,13 @@ import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Iterator;
 import java.util.List;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.poifs.storage.RawDataUtil;
 import org.apache.poi.util.LocaleUtil;
 import org.junit.jupiter.api.Test;
@@ -187,7 +187,7 @@ final class TestDirectoryProperty {
     }
 
     private void verifyProperty() throws IOException {
-        ByteArrayOutputStream stream = new ByteArrayOutputStream(512);
+        UnsynchronizedByteArrayOutputStream stream = new UnsynchronizedByteArrayOutputStream(512);
 
         _property.writeData(stream);
         byte[] output = stream.toByteArray();
@@ -253,7 +253,7 @@ final class TestDirectoryProperty {
 
     private static void verifyReadingProperty(int index, byte[] input, int offset, String name) {
         DirectoryProperty property = new DirectoryProperty(index, input, offset);
-        ByteArrayOutputStream stream = new ByteArrayOutputStream(128);
+        UnsynchronizedByteArrayOutputStream stream = new UnsynchronizedByteArrayOutputStream(128);
         byte[] expected = Arrays.copyOfRange(input, offset, offset+128);
         try {
             property.writeData(stream);
diff --git a/poi/src/test/java/org/apache/poi/poifs/property/TestDocumentProperty.java b/poi/src/test/java/org/apache/poi/poifs/property/TestDocumentProperty.java
index 17145cd9db..1bda3ab462 100644
--- a/poi/src/test/java/org/apache/poi/poifs/property/TestDocumentProperty.java
+++ b/poi/src/test/java/org/apache/poi/poifs/property/TestDocumentProperty.java
@@ -17,14 +17,15 @@
 
 package org.apache.poi.poifs.property;
 
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.util.Arrays;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.hpsf.DocumentSummaryInformation;
 import org.apache.poi.hpsf.SummaryInformation;
 import org.apache.poi.poifs.storage.RawDataUtil;
@@ -82,15 +83,13 @@ final class TestDocumentProperty {
             throws IOException {
         DocumentProperty      property = new DocumentProperty(index, input,
                                              offset);
-        ByteArrayOutputStream stream   = new ByteArrayOutputStream(128);
+        UnsynchronizedByteArrayOutputStream stream   = new UnsynchronizedByteArrayOutputStream(128);
         byte[]                expected = Arrays.copyOfRange(input, offset, offset+128);
         property.writeData(stream);
         byte[] output = stream.toByteArray();
 
         assertEquals(128, output.length);
-        for (int j = 0; j < 128; j++) {
-            assertEquals(expected[ j ], output[ j ], "mismatch at offset " + j);
-        }
+        assertArrayEquals(expected, output);
         assertEquals(index, property.getIndex());
         assertEquals(name, property.getName());
     }
@@ -146,15 +145,10 @@ final class TestDocumentProperty {
         {
             testblock[ index * 2 ] = name_bytes[ index ];
         }
-        ByteArrayOutputStream stream = new ByteArrayOutputStream(512);
+        UnsynchronizedByteArrayOutputStream stream = new UnsynchronizedByteArrayOutputStream(512);
 
         property.writeData(stream);
         byte[] output = stream.toByteArray();
-
-        assertEquals(testblock.length, output.length);
-        for (int j = 0; j < testblock.length; j++)
-        {
-            assertEquals(testblock[ j ], output[ j ], "mismatch at offset " + j);
-        }
+        assertArrayEquals(testblock, output);
     }
 }
diff --git a/poi/src/test/java/org/apache/poi/poifs/property/TestPropertyTable.java b/poi/src/test/java/org/apache/poi/poifs/property/TestPropertyTable.java
index e6ce6610f5..8a59f0f146 100644
--- a/poi/src/test/java/org/apache/poi/poifs/property/TestPropertyTable.java
+++ b/poi/src/test/java/org/apache/poi/poifs/property/TestPropertyTable.java
@@ -23,7 +23,6 @@ import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
@@ -31,6 +30,7 @@ import java.nio.ByteBuffer;
 import java.util.ArrayList;
 import java.util.List;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.hpsf.DocumentSummaryInformation;
 import org.apache.poi.hpsf.SummaryInformation;
 import org.apache.poi.poifs.common.POIFSConstants;
@@ -45,7 +45,7 @@ import org.junit.jupiter.api.Test;
 final class TestPropertyTable {
 
 	private static void confirmBlockEncoding(String expectedDataStr, PropertyTable table) throws IOException {
-		final ByteArrayOutputStream bos = new ByteArrayOutputStream();
+		final UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream();
 		byte[] expectedData = RawDataUtil.decompress(expectedDataStr);
 
 		POIFSStream stream = new POIFSStream(null) {
diff --git a/poi/src/test/java/org/apache/poi/poifs/property/TestRootProperty.java b/poi/src/test/java/org/apache/poi/poifs/property/TestRootProperty.java
index de51fcefde..04b42eff2e 100644
--- a/poi/src/test/java/org/apache/poi/poifs/property/TestRootProperty.java
+++ b/poi/src/test/java/org/apache/poi/poifs/property/TestRootProperty.java
@@ -17,13 +17,15 @@
 
 package org.apache.poi.poifs.property;
 
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
 
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.util.Arrays;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
+import org.apache.poi.hpsf.ClassIDPredefined;
 import org.apache.poi.poifs.common.POIFSConstants;
 import org.apache.poi.poifs.storage.RawDataUtil;
 import org.apache.poi.util.LocaleUtil;
@@ -39,7 +41,11 @@ final class TestRootProperty {
 	@Test
 	void testConstructor() throws IOException {
 		createBasicRootProperty();
-		verifyProperty();
+
+		UnsynchronizedByteArrayOutputStream stream = new UnsynchronizedByteArrayOutputStream(512);
+		_property.writeData(stream);
+		assertArrayEquals(_testblock, stream.toByteArray());
+
 	}
 
 	private void createBasicRootProperty() {
@@ -77,18 +83,6 @@ final class TestRootProperty {
 		}
 	}
 
-	private void verifyProperty() throws IOException {
-		ByteArrayOutputStream stream = new ByteArrayOutputStream(512);
-
-		_property.writeData(stream);
-		byte[] output = stream.toByteArray();
-
-		assertEquals(_testblock.length, output.length);
-		for (int j = 0; j < _testblock.length; j++) {
-			assertEquals(_testblock[j], output[j], "mismatch at offset " + j);
-		}
-	}
-
 	@Test
 	void testSetSize() {
 		for (int j = 0; j < 10; j++) {
@@ -99,27 +93,21 @@ final class TestRootProperty {
 	}
 
 	@Test
-	void testReadingConstructor() {
-		String[] input = {
+	void testReadingConstructor() throws IOException {
+		String[] inputBytes = {
 			"52 00 6F 00 6F 00 74 00 20 00 45 00 6E 00 74 00 72 00 79 00 00 00 00 00 00 00 00 00 00 00 00 00",
 			"00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00",
 			"16 00 05 01 FF FF FF FF FF FF FF FF 02 00 00 00 20 08 02 00 00 00 00 00 C0 00 00 00 00 00 00 46",
 			"00 00 00 00 00 00 00 00 00 00 00 00 C0 5C E8 23 9E 6B C1 01 FE FF FF FF 00 00 00 00 00 00 00 00",
 		};
-		verifyReadingProperty(0, RawDataUtil.decode(input), 0, "Root Entry",
-				"{00020820-0000-0000-C000-000000000046}");
-	}
+		int index = 0;
+		byte[] input = RawDataUtil.decode(inputBytes);
+		int offset = 0;
 
-	private void verifyReadingProperty(int index, byte[] input, int offset, String name,
-			String sClsId) {
 		RootProperty property = new RootProperty(index, input, offset);
-		ByteArrayOutputStream stream = new ByteArrayOutputStream(128);
+		UnsynchronizedByteArrayOutputStream stream = new UnsynchronizedByteArrayOutputStream(128);
 		byte[] expected = Arrays.copyOfRange(input, offset, offset+128);
-		try {
-			property.writeData(stream);
-		} catch (IOException e) {
-			throw new RuntimeException(e);
-		}
+		property.writeData(stream);
 		byte[] output = stream.toByteArray();
 
 		assertEquals(128, output.length);
@@ -127,8 +115,8 @@ final class TestRootProperty {
 			assertEquals(expected[j], output[j], "mismatch at offset " + j);
 		}
 		assertEquals(index, property.getIndex());
-		assertEquals(name, property.getName());
-        assertFalse(property.getChildren().hasNext());
-		assertEquals(property.getStorageClsid().toString(), sClsId);
+		assertEquals("Root Entry", property.getName());
+		assertFalse(property.getChildren().hasNext());
+		assertEquals(ClassIDPredefined.EXCEL_V8.getClassID(), property.getStorageClsid());
 	}
 }
diff --git a/poi/src/test/java/org/apache/poi/poifs/storage/RawDataUtil.java b/poi/src/test/java/org/apache/poi/poifs/storage/RawDataUtil.java
index b04741fb06..a349b5bedf 100644
--- a/poi/src/test/java/org/apache/poi/poifs/storage/RawDataUtil.java
+++ b/poi/src/test/java/org/apache/poi/poifs/storage/RawDataUtil.java
@@ -17,25 +17,25 @@
 package org.apache.poi.poifs.storage;
 
 import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.util.Base64;
 import java.util.zip.GZIPInputStream;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.util.HexRead;
 import org.apache.poi.util.IOUtils;
 
 /**
  * Test utility class.<br>
  *
- * Creates raw <code>byte[]</code> data from hex-dump String arrays.
+ * Creates raw {@code byte[]} data from hex-dump String arrays.
  */
 public final class RawDataUtil {
 
 	private RawDataUtil() {}
 
 	public static byte[] decode(String[] hexDataLines) {
-		ByteArrayOutputStream baos = new ByteArrayOutputStream(hexDataLines.length * 32 + 32);
+		UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream(hexDataLines.length * 32 + 32);
 
 		for (String hexDataLine : hexDataLines) {
 			byte[] lineData = HexRead.readFromString(hexDataLine);
@@ -64,7 +64,7 @@ public final class RawDataUtil {
      * @throws IOException usually not ...
      */
     public static String compress(byte[] data) throws IOException {
-        java.io.ByteArrayOutputStream bos = new java.io.ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream();
         java.util.zip.GZIPOutputStream gz = new java.util.zip.GZIPOutputStream(bos);
         gz.write(data);
         gz.finish();
diff --git a/poi/src/test/java/org/apache/poi/sl/usermodel/BaseTestSlideShow.java b/poi/src/test/java/org/apache/poi/sl/usermodel/BaseTestSlideShow.java
index 81f5931f34..0654012411 100644
--- a/poi/src/test/java/org/apache/poi/sl/usermodel/BaseTestSlideShow.java
+++ b/poi/src/test/java/org/apache/poi/sl/usermodel/BaseTestSlideShow.java
@@ -160,17 +160,16 @@ public abstract class BaseTestSlideShow<
     @Test
     void shapeAndSlideName() throws IOException {
         final String file = "SampleShow.ppt"+(getClass().getSimpleName().contains("XML")?"x":"");
-        //noinspection unchecked
         try (final InputStream is = slTests.openResourceAsStream(file);
-             final SlideShow<S,P> ppt = (SlideShow<S,P>)SlideShowFactory.create(is)) {
-            final List<S> shapes1 = ppt.getSlides().get(0).getShapes();
+             final SlideShow<? extends Shape<?,?>,?> ppt = SlideShowFactory.create(is)) {
+            final List<? extends Shape<?,?>> shapes1 = ppt.getSlides().get(0).getShapes();
             assertEquals("The Title", shapes1.get(0).getShapeName());
             assertEquals("Another Subtitle", shapes1.get(1).getShapeName());
-            final List<S> shapes2 = ppt.getSlides().get(1).getShapes();
+            final List<? extends Shape<?,?>> shapes2 = ppt.getSlides().get(1).getShapes();
             assertEquals("Title 1", shapes2.get(0).getShapeName());
             assertEquals("Content Placeholder 2", shapes2.get(1).getShapeName());
 
-            for (final Slide<S,P> slide : ppt.getSlides()) {
+            for (final Slide<? extends Shape<?,?>,?> slide : ppt.getSlides()) {
                 final String expected = slide.getSlideNumber()==1 ? "FirstSlide" : "Slide2";
                 assertEquals(expected, slide.getSlideName());
             }
diff --git a/poi/src/test/java/org/apache/poi/sl/usermodel/BaseTestSlideShowFactory.java b/poi/src/test/java/org/apache/poi/sl/usermodel/BaseTestSlideShowFactory.java
index 090aeb0aa8..02d84fac03 100644
--- a/poi/src/test/java/org/apache/poi/sl/usermodel/BaseTestSlideShowFactory.java
+++ b/poi/src/test/java/org/apache/poi/sl/usermodel/BaseTestSlideShowFactory.java
@@ -21,13 +21,13 @@ import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.POIDataSamples;
 import org.apache.poi.poifs.filesystem.POIFSFileSystem;
 
@@ -133,10 +133,9 @@ public abstract class BaseTestSlideShowFactory {
     }
 
     private static byte[] readExternalFile(String path) {
-        ByteArrayOutputStream baos = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
 
-        try {
-            InputStream fis = new FileInputStream(path);
+        try (InputStream fis = new FileInputStream(path)) {
             byte[] buf = new byte[512];
             while (true) {
                 int bytesRead = fis.read(buf);
@@ -145,7 +144,6 @@ public abstract class BaseTestSlideShowFactory {
                 }
                 baos.write(buf, 0, bytesRead);
             }
-            fis.close();
         } catch (final IOException e) {
             throw new RuntimeException(e);
         }
diff --git a/poi/src/test/java/org/apache/poi/ss/usermodel/BaseTestBugzillaIssues.java b/poi/src/test/java/org/apache/poi/ss/usermodel/BaseTestBugzillaIssues.java
index bcd8bf272a..5e7b5d87f7 100644
--- a/poi/src/test/java/org/apache/poi/ss/usermodel/BaseTestBugzillaIssues.java
+++ b/poi/src/test/java/org/apache/poi/ss/usermodel/BaseTestBugzillaIssues.java
@@ -32,13 +32,13 @@ import java.awt.font.FontRenderContext;
 import java.awt.font.TextAttribute;
 import java.awt.font.TextLayout;
 import java.awt.geom.Rectangle2D;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.text.AttributedString;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.poi.hssf.usermodel.HSSFWorkbook;
@@ -1817,8 +1817,8 @@ public abstract class BaseTestBugzillaIssues {
             cell.setCellValue("Ernie & Bert are cool!");
             cell.setCellFormula("A1 & \" are cool!\"");
 
-            try (ByteArrayOutputStream out1 = new ByteArrayOutputStream();
-                 ByteArrayOutputStream out2 = new ByteArrayOutputStream()) {
+            try (UnsynchronizedByteArrayOutputStream out1 = new UnsynchronizedByteArrayOutputStream();
+                 UnsynchronizedByteArrayOutputStream out2 = new UnsynchronizedByteArrayOutputStream()) {
                 wb.write(out1);
                 wb.write(out2);
 
diff --git a/poi/src/test/java/org/apache/poi/ss/usermodel/BaseTestPicture.java b/poi/src/test/java/org/apache/poi/ss/usermodel/BaseTestPicture.java
index d79e594857..af3c773d00 100644
--- a/poi/src/test/java/org/apache/poi/ss/usermodel/BaseTestPicture.java
+++ b/poi/src/test/java/org/apache/poi/ss/usermodel/BaseTestPicture.java
@@ -32,12 +32,12 @@ import java.awt.geom.Ellipse2D;
 import java.awt.geom.Rectangle2D;
 import java.awt.image.BufferedImage;
 import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.util.Arrays;
 
 import javax.imageio.ImageIO;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.hssf.HSSFITestDataProvider;
 import org.apache.poi.hssf.usermodel.HSSFWorkbook;
 import org.apache.poi.ss.ITestDataProvider;
@@ -272,7 +272,7 @@ public abstract class BaseTestPicture {
         g.draw(ell);
 
         g.dispose();
-        ByteArrayOutputStream bos = new ByteArrayOutputStream(2000);
+        UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream(2000);
         ImageIO.write(bi, "PNG", bos);
         return bos.toByteArray();
     }
diff --git a/poi/src/test/java/org/apache/poi/ss/usermodel/BaseTestWorkbook.java b/poi/src/test/java/org/apache/poi/ss/usermodel/BaseTestWorkbook.java
index 11bb3c9357..a38ec3448f 100644
--- a/poi/src/test/java/org/apache/poi/ss/usermodel/BaseTestWorkbook.java
+++ b/poi/src/test/java/org/apache/poi/ss/usermodel/BaseTestWorkbook.java
@@ -17,6 +17,7 @@
 
 package org.apache.poi.ss.usermodel;
 
+import static org.apache.commons.io.output.NullOutputStream.NULL_OUTPUT_STREAM;
 import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
 import static org.junit.jupiter.api.Assertions.assertEquals;
@@ -28,7 +29,6 @@ import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.io.IOException;
-import java.io.OutputStream;
 import java.util.ConcurrentModificationException;
 import java.util.Iterator;
 
@@ -37,7 +37,6 @@ import org.apache.poi.ss.ITestDataProvider;
 import org.apache.poi.ss.usermodel.ClientAnchor.AnchorType;
 import org.apache.poi.ss.util.CellAddress;
 import org.apache.poi.ss.util.CellRangeAddress;
-import org.apache.poi.util.NullOutputStream;
 import org.junit.jupiter.api.Test;
 
 public abstract class BaseTestWorkbook {
@@ -775,7 +774,7 @@ public abstract class BaseTestWorkbook {
                 c.setCellStyle(cs);
                 c.setCellValue("AAA");
             }
-            assertDoesNotThrow(() -> workbook.write(new NullOutputStream()));
+            assertDoesNotThrow(() -> workbook.write(NULL_OUTPUT_STREAM));
         }
     }
 
diff --git a/poi/src/test/java/org/apache/poi/ss/util/NumberRenderingSpreadsheetGenerator.java b/poi/src/test/java/org/apache/poi/ss/util/NumberRenderingSpreadsheetGenerator.java
index c2ef0dfdc1..1676d0daae 100644
--- a/poi/src/test/java/org/apache/poi/ss/util/NumberRenderingSpreadsheetGenerator.java
+++ b/poi/src/test/java/org/apache/poi/ss/util/NumberRenderingSpreadsheetGenerator.java
@@ -18,7 +18,6 @@
 package org.apache.poi.ss.util;
 
 import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.DataInputStream;
 import java.io.File;
 import java.io.FileOutputStream;
@@ -28,6 +27,7 @@ import java.util.ArrayList;
 import java.util.List;
 import java.util.Locale;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.hssf.usermodel.HSSFCell;
 import org.apache.poi.hssf.usermodel.HSSFCellStyle;
 import org.apache.poi.hssf.usermodel.HSSFFont;
@@ -148,25 +148,20 @@ public class NumberRenderingSpreadsheetGenerator {
 			sw.addTestRow(example.getRawDoubleBits(), example.getExcelRendering());
 		}
 
-		ByteArrayOutputStream baos = new ByteArrayOutputStream();
-		try {
-			wb.write(baos);
-		} catch (IOException e) {
-			throw new RuntimeException(e);
-		}
-		byte[] fileContent = baos.toByteArray();
-		replaceNaNs(fileContent, sw.getReplacementNaNs());
+		File outputFile = new File("ExcelNumberRendering.xls");
 
+		try (UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
+			 FileOutputStream os = new FileOutputStream(outputFile)) {
+			wb.write(baos);
 
-		File outputFile = new File("ExcelNumberRendering.xls");
+			byte[] fileContent = baos.toByteArray();
+			replaceNaNs(fileContent, sw.getReplacementNaNs());
 
-		try {
-			FileOutputStream os = new FileOutputStream(outputFile);
 			os.write(fileContent);
-			os.close();
 		} catch (IOException e) {
 			throw new RuntimeException(e);
 		}
+
 		System.out.println("Finished writing '" + outputFile.getAbsolutePath() + "'");
 	}
 
diff --git a/poi/src/test/java/org/apache/poi/ss/util/TestCellRangeAddress.java b/poi/src/test/java/org/apache/poi/ss/util/TestCellRangeAddress.java
index 01d12f41c3..033fb5f179 100644
--- a/poi/src/test/java/org/apache/poi/ss/util/TestCellRangeAddress.java
+++ b/poi/src/test/java/org/apache/poi/ss/util/TestCellRangeAddress.java
@@ -25,11 +25,11 @@ import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 import static org.junit.jupiter.api.Assertions.fail;
 
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.util.Iterator;
 import java.util.NoSuchElementException;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.hssf.record.TestcaseRecordInputStream;
 import org.apache.poi.util.LittleEndianOutputStream;
 import org.junit.jupiter.api.Test;
@@ -64,7 +64,7 @@ final class TestCellRangeAddress {
         CellRangeAddress ref = new CellRangeAddress(0, 0, 0, 0);
 
         byte[] recordBytes;
-        ByteArrayOutputStream baos = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
         try (LittleEndianOutputStream out = new LittleEndianOutputStream(baos)) {
             // With nothing set
             ref.serialize(out);
@@ -100,7 +100,7 @@ final class TestCellRangeAddress {
     }
 
     @Test
-    void testCopy() throws IOException {
+    void testCopy() {
         CellRangeAddress ref = new CellRangeAddress(1, 2, 3, 4);
         CellRangeAddress copy = ref.copy();
         assertEquals(ref.toString(), copy.toString());
diff --git a/poi/src/test/java/org/apache/poi/ss/util/TestDateFormatConverter.java b/poi/src/test/java/org/apache/poi/ss/util/TestDateFormatConverter.java
index befe219a16..0faf865e5a 100644
--- a/poi/src/test/java/org/apache/poi/ss/util/TestDateFormatConverter.java
+++ b/poi/src/test/java/org/apache/poi/ss/util/TestDateFormatConverter.java
@@ -22,6 +22,7 @@ package org.apache.poi.ss.util;
 import static java.text.DateFormat.getDateInstance;
 import static java.text.DateFormat.getDateTimeInstance;
 import static java.text.DateFormat.getTimeInstance;
+import static org.apache.commons.io.output.NullOutputStream.NULL_OUTPUT_STREAM;
 import static org.apache.poi.ss.util.DateFormatConverter.getPrefixForLocale;
 import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
 import static org.junit.jupiter.api.Assertions.assertEquals;
@@ -50,7 +51,6 @@ import org.apache.poi.ss.usermodel.Row;
 import org.apache.poi.ss.usermodel.Sheet;
 import org.apache.poi.ss.usermodel.Workbook;
 import org.apache.poi.util.LocaleID;
-import org.apache.poi.util.NullOutputStream;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.CsvSource;
@@ -122,7 +122,7 @@ final class TestDateFormatConverter {
                 cell[6].setCellValue(excelFormatPattern);
             }
 
-            assertDoesNotThrow(() -> workbook.write(new NullOutputStream()));
+            assertDoesNotThrow(() -> workbook.write(NULL_OUTPUT_STREAM));
         }
     }
 
diff --git a/poi/src/test/java/org/apache/poi/util/NullOutputStream.java b/poi/src/test/java/org/apache/poi/util/NullOutputStream.java
deleted file mode 100644
index ac76123a3c..0000000000
--- a/poi/src/test/java/org/apache/poi/util/NullOutputStream.java
+++ /dev/null
@@ -1,41 +0,0 @@
-/* ====================================================================
-   Licensed to the Apache Software Foundation (ASF) under one or more
-   contributor license agreements.  See the NOTICE file distributed with
-   this work for additional information regarding copyright ownership.
-   The ASF licenses this file to You under the Apache License, Version 2.0
-   (the "License"); you may not use this file except in compliance with
-   the License.  You may obtain a copy of the License at
-
-       http://www.apache.org/licenses/LICENSE-2.0
-
-   Unless required by applicable law or agreed to in writing, software
-   distributed under the License is distributed on an "AS IS" BASIS,
-   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-   See the License for the specific language governing permissions and
-   limitations under the License.
-==================================================================== */
-
-package org.apache.poi.util;
-
-import java.io.OutputStream;
-
-/**
- * Implementation of an OutputStream which does nothing, used
- * to redirect stdout to avoid spamming the console with output
- */
-public final class NullOutputStream extends OutputStream {
-    public NullOutputStream() {
-    }
-
-    @Override
-    public void write(byte[] b, int off, int len) {
-    }
-
-    @Override
-    public void write(int b) {
-    }
-
-    @Override
-    public void write(byte[] b) {
-    }
-}
diff --git a/poi/src/test/java/org/apache/poi/util/NullPrintStream.java b/poi/src/test/java/org/apache/poi/util/NullPrintStream.java
deleted file mode 100644
index 5fd6bc64ad..0000000000
--- a/poi/src/test/java/org/apache/poi/util/NullPrintStream.java
+++ /dev/null
@@ -1,88 +0,0 @@
-/* ====================================================================
-   Licensed to the Apache Software Foundation (ASF) under one or more
-   contributor license agreements.  See the NOTICE file distributed with
-   this work for additional information regarding copyright ownership.
-   The ASF licenses this file to You under the Apache License, Version 2.0
-   (the "License"); you may not use this file except in compliance with
-   the License.  You may obtain a copy of the License at
-
-       http://www.apache.org/licenses/LICENSE-2.0
-
-   Unless required by applicable law or agreed to in writing, software
-   distributed under the License is distributed on an "AS IS" BASIS,
-   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-   See the License for the specific language governing permissions and
-   limitations under the License.
-==================================================================== */
-
-package org.apache.poi.util;
-
-import java.io.PrintStream;
-import java.util.Locale;
-
-// need to override all methods to omit calls to UTF-handling methods
-@SuppressForbidden("ignore super constructor with charset - omits declaring UnsupportedEncodingException")
-public class NullPrintStream extends PrintStream {
-    @SuppressWarnings("resource")
-    public NullPrintStream() {
-        super(new NullOutputStream(), true);
-    }
-    @Override
-    public void write(int b) {}
-    @Override
-    public void write(byte[] buf, int off, int len) {}
-    @Override
-    public void print(boolean b) {}
-    @Override
-    public void print(char c) {}
-    @Override
-    public void print(int i) {}
-    @Override
-    public void print(long l) {}
-    @Override
-    public void print(float f) {}
-    @Override
-    public void print(double d) {}
-    @Override
-    public void print(char[] s) {}
-    @Override
-    public void print(String s) {}
-    @Override
-    public void print(Object obj) {}
-    @Override
-    public void println() {}
-    @Override
-    public void println(boolean x) {}
-    @Override
-    public void println(char x) {}
-    @Override
-    public void println(int x) {}
-    @Override
-    public void println(long x) {}
-    @Override
-    public void println(float x) {}
-    @Override
-    public void println(double x) {}
-    @Override
-    public void println(char[] x) {}
-    @Override
-    public void println(String x) {}
-    @Override
-    public void println(Object x) {}
-    @Override
-    public PrintStream printf(String format, Object... args) { return this; }
-    @Override
-    public PrintStream printf(Locale l, String format, Object... args) { return this; }
-    @Override
-    public PrintStream format(String format, Object... args) { return this; }
-    @Override
-    public PrintStream format(Locale l, String format, Object... args) { return this; }
-    @Override
-    public PrintStream append(CharSequence csq) { return this; }
-    @Override
-    public PrintStream append(CharSequence csq, int start, int end) { return this; }
-    @Override
-    public PrintStream append(char c) { return this; }
-    @Override
-    public void write(byte[] b) {}
-}
diff --git a/poi/src/test/java/org/apache/poi/util/TestHexDump.java b/poi/src/test/java/org/apache/poi/util/TestHexDump.java
index 4a465cb4be..70ce3ab333 100644
--- a/poi/src/test/java/org/apache/poi/util/TestHexDump.java
+++ b/poi/src/test/java/org/apache/poi/util/TestHexDump.java
@@ -22,11 +22,12 @@ import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.PrintStream;
 import java.io.UnsupportedEncodingException;
 
+import org.apache.commons.io.output.NullPrintStream;
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.junit.jupiter.api.AfterAll;
 import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.Test;
@@ -51,7 +52,7 @@ class TestHexDump {
     @Test
     void testDump() throws IOException {
         byte[] testArray = testArray();
-        ByteArrayOutputStream streamAct = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream streamAct = new UnsynchronizedByteArrayOutputStream();
         HexDump.dump(testArray, 0, streamAct, 0);
         byte[] bytesAct = streamAct.toByteArray();
         byte[] bytesExp = toHexDump(0, 0);
diff --git a/poi/src/test/java/org/apache/poi/util/TestIOUtils.java b/poi/src/test/java/org/apache/poi/util/TestIOUtils.java
index d09dc5912e..54e45ae557 100644
--- a/poi/src/test/java/org/apache/poi/util/TestIOUtils.java
+++ b/poi/src/test/java/org/apache/poi/util/TestIOUtils.java
@@ -25,7 +25,6 @@ import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.EOFException;
 import java.io.File;
 import java.io.FileInputStream;
@@ -39,6 +38,7 @@ import java.nio.channels.ReadableByteChannel;
 import java.nio.charset.StandardCharsets;
 import java.util.Random;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.EmptyFileException;
 import org.junit.jupiter.api.AfterAll;
 import org.junit.jupiter.api.BeforeAll;
@@ -161,20 +161,20 @@ final class TestIOUtils {
 
     @Test
     void testSkipFullyByteArray() throws IOException {
-        ByteArrayOutputStream bos = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream();
         try (InputStream is = new FileInputStream(TMP)) {
             assertEquals(LENGTH, IOUtils.copy(is, bos));
-            long skipped = IOUtils.skipFully(new ByteArrayInputStream(bos.toByteArray()), 20000L);
+            long skipped = IOUtils.skipFully(bos.toInputStream(), 20000L);
             assertEquals(LENGTH, skipped);
         }
     }
 
     @Test
     void testSkipFullyByteArrayGtIntMax() throws IOException {
-        ByteArrayOutputStream bos = new ByteArrayOutputStream();
+        UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream();
         try (InputStream is = new FileInputStream(TMP)) {
             assertEquals(LENGTH, IOUtils.copy(is, bos));
-            long skipped = IOUtils.skipFully(new ByteArrayInputStream(bos.toByteArray()), Integer.MAX_VALUE + 20000L);
+            long skipped = IOUtils.skipFully(bos.toInputStream(), Integer.MAX_VALUE + 20000L);
             assertEquals(LENGTH, skipped);
         }
     }
diff --git a/poi/src/test/java/org/apache/poi/util/TestLittleEndianStreams.java b/poi/src/test/java/org/apache/poi/util/TestLittleEndianStreams.java
index 54ebefa5b5..dcb89d5a35 100644
--- a/poi/src/test/java/org/apache/poi/util/TestLittleEndianStreams.java
+++ b/poi/src/test/java/org/apache/poi/util/TestLittleEndianStreams.java
@@ -23,10 +23,9 @@ import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.junit.jupiter.api.Test;
 
 /**
@@ -36,7 +35,7 @@ final class TestLittleEndianStreams {
 
 	@Test
 	void testRead() throws IOException {
-		ByteArrayOutputStream baos = new ByteArrayOutputStream();
+		UnsynchronizedByteArrayOutputStream baos = new UnsynchronizedByteArrayOutputStream();
 		try (LittleEndianOutputStream leo = new LittleEndianOutputStream(baos)) {
 			leo.writeInt(12345678);
 			leo.writeShort(12345);
@@ -47,7 +46,7 @@ final class TestLittleEndianStreams {
 			leo.writeDouble(123.456);
 		}
 
-		try (LittleEndianInputStream lei = new LittleEndianInputStream(new ByteArrayInputStream(baos.toByteArray()))) {
+		try (LittleEndianInputStream lei = new LittleEndianInputStream(baos.toInputStream())) {
 			assertEquals(12345678, lei.readInt());
 			assertEquals(12345, lei.readShort());
 			assertEquals(123, lei.readByte());
diff --git a/poi/src/test/java/org/apache/poi/util/TestRLEDecompressingInputStream.java b/poi/src/test/java/org/apache/poi/util/TestRLEDecompressingInputStream.java
index 219e1460b1..0c8fad889e 100644
--- a/poi/src/test/java/org/apache/poi/util/TestRLEDecompressingInputStream.java
+++ b/poi/src/test/java/org/apache/poi/util/TestRLEDecompressingInputStream.java
@@ -21,11 +21,10 @@ import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
-import java.io.UnsupportedEncodingException;
 
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.junit.jupiter.api.Test;
 
 class TestRLEDecompressingInputStream {
@@ -55,7 +54,7 @@ class TestRLEDecompressingInputStream {
      *
      */
     @Test
-    void noCompressionExample() {
+    void noCompressionExample() throws IOException {
         final byte[] compressed = {
             0x01, 0x19, (byte)0xB0, 0x00, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x00, 0x69, 0x6A, 0x6B, 0x6C,
             0x6D, 0x6E, 0x6F, 0x70, 0x00, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x2E
@@ -92,7 +91,7 @@ class TestRLEDecompressingInputStream {
      *     76 77 78 79 7A 61 61 61
      */
     @Test
-    void normalCompressionExample() {
+    void normalCompressionExample() throws IOException {
         final byte[] compressed = {
             0x01, 0x2F, (byte)0xB0, 0x00, 0x23, 0x61, 0x61, 0x61, 0x62, 0x63, 0x64, 0x65, (byte)0x82, 0x66, 0x00, 0x70,
             0x61, 0x67, 0x68, 0x69, 0x6A, 0x01, 0x38, 0x08, 0x61, 0x6B, 0x6C, 0x00, 0x30, 0x6D, 0x6E, 0x6F,
@@ -129,7 +128,7 @@ class TestRLEDecompressingInputStream {
      *     61 61 61 61 61 61 61 61  61
      */
     @Test
-    void maximumCompressionExample() {
+    void maximumCompressionExample() throws IOException {
         final byte[] compressed = {
             0x01, 0x03, (byte)0xB0, 0x02, 0x61, 0x45, 0x00
         };
@@ -147,26 +146,13 @@ class TestRLEDecompressingInputStream {
         assertArrayEquals(expected, expanded);
     }
 
-    private static void checkRLEDecompression(String expected, byte[] runLengthEncodedData) {
+    private static void checkRLEDecompression(String expected, byte[] runLengthEncodedData) throws IOException {
         InputStream compressedStream = new ByteArrayInputStream(runLengthEncodedData);
-        ByteArrayOutputStream out = new ByteArrayOutputStream();
-        try {
-            InputStream stream = new RLEDecompressingInputStream(compressedStream);
-            try {
-                IOUtils.copy(stream, out);
-            } finally {
-                out.close();
-                stream.close();
-            }
-        } catch (final IOException e) {
-            throw new RuntimeException(e);
-        }
-        String expanded;
-        try {
-            expanded = out.toString(StringUtil.UTF8.name());
-        } catch (final UnsupportedEncodingException e) {
-            throw new RuntimeException(e);
+        UnsynchronizedByteArrayOutputStream out = new UnsynchronizedByteArrayOutputStream();
+        try (InputStream stream = new RLEDecompressingInputStream(compressedStream)) {
+            IOUtils.copy(stream, out);
         }
+        String expanded = out.toString(StringUtil.UTF8);
         assertEquals(expected, expanded);
     }
 }
diff --git a/sonar/main/pom.xml b/sonar/main/pom.xml
index d5c2aeefa7..b8b44e301a 100644
--- a/sonar/main/pom.xml
+++ b/sonar/main/pom.xml
@@ -124,6 +124,11 @@
             <version>3.6.1</version>
         </dependency>
         <dependency>
+            <groupId>commons-io</groupId>
+            <artifactId>commons-io</artifactId>
+            <version>2.8.0</version>
+        </dependency>
+        <dependency>
             <groupId>com.zaxxer</groupId>
             <artifactId>SparseBitSet</artifactId>
             <version>1.2</version>