Apply some IDE suggestions, JavaDoc and GitHub PR

Update assertion-message
Adjust JavaDoc
Add tests
Reformat class DirectoryNode, adjust/move some comments

Closes #730

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1921980 13f79535-47bb-0310-9956-ffa450edef68

10 files changed, 147 insertions, 174 deletions

diff --git a/poi-ooxml/src/main/java/org/apache/poi/poifs/crypt/dsig/SignatureConfig.java b/poi-ooxml/src/main/java/org/apache/poi/poifs/crypt/dsig/SignatureConfig.java
index 5888732c47..2764644812 100644
--- a/poi-ooxml/src/main/java/org/apache/poi/poifs/crypt/dsig/SignatureConfig.java
+++ b/poi-ooxml/src/main/java/org/apache/poi/poifs/crypt/dsig/SignatureConfig.java
@@ -26,7 +26,6 @@ import java.security.GeneralSecurityException;
 import java.security.KeyStore;
 import java.security.KeyStoreException;
 import java.security.PrivateKey;
-import java.security.Provider;
 import java.security.cert.Certificate;
 import java.security.cert.CertificateException;
 import java.security.cert.CertificateFactory;
@@ -52,14 +51,11 @@ import javax.xml.crypto.URIDereferencer;
 import javax.xml.crypto.dsig.CanonicalizationMethod;
 import javax.xml.crypto.dsig.DigestMethod;
 import javax.xml.crypto.dsig.Transform;
-import javax.xml.crypto.dsig.XMLSignatureFactory;
-import javax.xml.crypto.dsig.keyinfo.KeyInfoFactory;
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.poi.EncryptedDocumentException;
 import org.apache.poi.hpsf.ClassID;
-import org.apache.poi.openxml4j.opc.OPCPackage;
 import org.apache.poi.poifs.crypt.HashAlgorithm;
 import org.apache.poi.poifs.crypt.dsig.facets.KeyInfoSignatureFacet;
 import org.apache.poi.poifs.crypt.dsig.facets.OOXMLSignatureFacet;
@@ -73,7 +69,6 @@ import org.apache.poi.poifs.crypt.dsig.services.TimeStampHttpClient;
 import org.apache.poi.poifs.crypt.dsig.services.TimeStampService;
 import org.apache.poi.poifs.crypt.dsig.services.TimeStampServiceValidator;
 import org.apache.poi.poifs.crypt.dsig.services.TimeStampSimpleHttpClient;
-import org.apache.poi.util.Internal;
 import org.apache.poi.util.LocaleUtil;
 import org.apache.poi.util.Removal;
 import org.apache.xml.security.signature.XMLSignature;
@@ -382,7 +377,7 @@ public class SignatureConfig {
      * @since POI 4.0.0
      */
     public void setExecutionTime(String executionTime) {
-        if (executionTime != null && !"".equals(executionTime)){
+        if (executionTime != null && !executionTime.isEmpty()){
             final DateFormat fmt = new SimpleDateFormat(SIGNATURE_TIME_FORMAT, Locale.ROOT);
             fmt.setTimeZone(LocaleUtil.TIMEZONE_UTC);
             try {
@@ -992,12 +987,12 @@ public class SignatureConfig {
      * <li>the JDK xmlsec provider</li>
      * </ol>
      *
-     * @return a list of possible XMLSEC provider class names
+     * @return an array of possible XMLSEC provider class names
      */
     public static String[] getProviderNames() {
         // need to check every time, as the system property might have been changed in the meantime
         String sysProp = System.getProperty("jsr105Provider");
-        return (sysProp == null || "".equals(sysProp))
+        return (sysProp == null || sysProp.isEmpty())
             ? new String[]{XMLSEC_SANTUARIO, XMLSEC_JDK}
             : new String[]{sysProp, XMLSEC_SANTUARIO, XMLSEC_JDK};
     }
@@ -1031,7 +1026,7 @@ public class SignatureConfig {
 
     /**
      * The signature config can be updated if a document is succesful validated.
-     * This flag is used for activating this modifications.
+     * This flag is used for activating these modifications.
      * Defaults to {@code false}
      *
      * @param updateConfigOnValidate if true, update config on validate
diff --git a/poi-ooxml/src/test/java/org/apache/poi/xslf/usermodel/TestXSLFTextParagraph.java b/poi-ooxml/src/test/java/org/apache/poi/xslf/usermodel/TestXSLFTextParagraph.java
index f6c5570003..7580745404 100644
--- a/poi-ooxml/src/test/java/org/apache/poi/xslf/usermodel/TestXSLFTextParagraph.java
+++ b/poi-ooxml/src/test/java/org/apache/poi/xslf/usermodel/TestXSLFTextParagraph.java
@@ -19,6 +19,7 @@ package org.apache.poi.xslf.usermodel;
 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;
+import static org.junit.jupiter.api.Assertions.assertInstanceOf;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertNull;
 import static org.junit.jupiter.api.Assertions.assertThrows;
@@ -467,21 +468,21 @@ class TestXSLFTextParagraph {
                         attributes = iterator.getAttributes();
                     }
 
-                    if ("This is a".equals(sb.toString())) {
+                    if ("This is a".contentEquals(sb)) {
                         // Should be no background.
                         assertNotNull(attributes);
                         Object background = attributes.get(TextAttribute.BACKGROUND);
                         assertNull(background);
                     }
-                    if ("highlight".equals(sb.toString())) {
+                    if ("highlight".contentEquals(sb)) {
                         // Should be yellow background.
                         assertNotNull(attributes);
                         Object background = attributes.get(TextAttribute.BACKGROUND);
                         assertNotNull(background);
-                        assertTrue(background instanceof Color);
+                        assertInstanceOf(Color.class, background);
                         assertEquals(Color.yellow, background);
                     }
-                    if (" test".equals(sb.toString())) {
+                    if (" test".contentEquals(sb)) {
                         // Should be no background.
                         assertNotNull(attributes);
                         Object background = attributes.get(TextAttribute.BACKGROUND);
@@ -494,5 +495,4 @@ class TestXSLFTextParagraph {
             ppt.getSlides().get(0).draw(dgfx);
         }
     }
-
 }
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 7901b438d7..ae2f3c37f2 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
@@ -3331,7 +3331,7 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
             LOG.atInfo().log(between(start, now()));
 
             assertTrue(between(start, now()).getSeconds() < 25,
-                    "Had start: " + start + ", now: " + now() +
+                    "Expected to have less than 25s duration for test, but had start: " + start + ", now: " + now() +
                             ", diff: " + Duration.between(start, now()).getSeconds());
         }
     }
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 64a3a31c21..b409748504 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
@@ -447,8 +447,9 @@ public abstract class PropertiesChunk extends Chunk {
     /**
      * Writes out pre-calculated raw values which assume any variable length property `data`
      *  field to already have size, reserved and manually written header
-     * @param out
-     * @throws IOException
+     *
+     * @param out The OutputStream to write the data to
+     * @throws IOException If an I/O error occurs while writing data
      */
     private void writeVariableLengthPreCalculatedValue(OutputStream out, PropertyValue value) throws IOException {
         // variable length header
diff --git a/poi-scratchpad/src/main/java/org/apache/poi/hwpf/HWPFDocument.java b/poi-scratchpad/src/main/java/org/apache/poi/hwpf/HWPFDocument.java
index 12577ea186..3c4275b2a9 100644
--- a/poi-scratchpad/src/main/java/org/apache/poi/hwpf/HWPFDocument.java
+++ b/poi-scratchpad/src/main/java/org/apache/poi/hwpf/HWPFDocument.java
@@ -291,7 +291,7 @@ public final class HWPFDocument extends HWPFDocumentCore {
         _text = _tpt.getText();
 
         /*
-         * in this mode we preserving PAPX/CHPX structure from file, so text may
+         * in this mode we are preserving PAPX/CHPX structure from file, so text may
          * miss from output, and text order may be corrupted
          */
         boolean preserveBinTables = false;
diff --git a/poi/src/main/java/org/apache/poi/hssf/record/RecordFactory.java b/poi/src/main/java/org/apache/poi/hssf/record/RecordFactory.java
index d665ba0eb9..16f1a04d04 100644
--- a/poi/src/main/java/org/apache/poi/hssf/record/RecordFactory.java
+++ b/poi/src/main/java/org/apache/poi/hssf/record/RecordFactory.java
@@ -173,7 +173,7 @@ public final class RecordFactory {
      *
      * @param in the InputStream from which the records will be obtained
      *
-     * @return an array of Records created from the InputStream
+     * @return a list of Records created from the InputStream
      *
      * @throws org.apache.poi.util.RecordFormatException on error processing the InputStream
      */
diff --git a/poi/src/main/java/org/apache/poi/poifs/filesystem/DirectoryNode.java b/poi/src/main/java/org/apache/poi/poifs/filesystem/DirectoryNode.java
index 6e7f7508d0..07945f97cd 100644
--- a/poi/src/main/java/org/apache/poi/poifs/filesystem/DirectoryNode.java
+++ b/poi/src/main/java/org/apache/poi/poifs/filesystem/DirectoryNode.java
@@ -16,16 +16,13 @@
    limitations under the License.
 ==================================================================== */
 
-
 package org.apache.poi.poifs.filesystem;
 
 import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.io.InputStream;
 import java.util.ArrayList;
-import java.util.Collections;
 import java.util.HashMap;
-import java.util.HashSet;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Locale;
@@ -44,8 +41,7 @@ import org.apache.poi.poifs.property.Property;
  */
 public class DirectoryNode
         extends EntryNode
-        implements DirectoryEntry, POIFSViewable, Iterable<Entry>
-{
+        implements DirectoryEntry, POIFSViewable, Iterable<Entry> {
 
     // Map of Entry instances, keyed by their literal names as stored
     private final Map<String,Entry> _byname = new HashMap<>();
@@ -72,36 +68,25 @@ public class DirectoryNode
      */
     DirectoryNode(final DirectoryProperty property,
                   final POIFSFileSystem filesystem,
-                  final DirectoryNode parent)
-    {
+                  final DirectoryNode parent) {
         super(property, parent);
         this._filesystem = filesystem;
 
-        if (parent == null)
-        {
+        if (parent == null) {
             _path = new POIFSDocumentPath();
-        }
-        else
-        {
-            _path = new POIFSDocumentPath(parent._path, new String[]
-                    {
-                            property.getName()
-                    });
+        } else {
+            _path = new POIFSDocumentPath(parent._path, new String[] { property.getName() });
         }
         Iterator<Property> iter = property.getChildren();
 
-        while (iter.hasNext())
-        {
-            Property child     = iter.next();
-            Entry    childNode;
+        while (iter.hasNext()) {
+            Property child = iter.next();
+            Entry childNode;
 
-            if (child.isDirectory())
-            {
+            if (child.isDirectory()) {
                 DirectoryProperty childDir = (DirectoryProperty) child;
                 childNode = new DirectoryNode(childDir, _filesystem, this);
-            }
-            else
-            {
+            } else {
                 childNode = new DocumentNode((DocumentProperty) child, this);
             }
             _entries.add(childNode);
@@ -113,17 +98,14 @@ public class DirectoryNode
     /**
      * @return this directory's path representation
      */
-
-    public POIFSDocumentPath getPath()
-    {
+    public POIFSDocumentPath getPath() {
         return _path;
     }
 
     /**
      * @return the filesystem that this belongs to
      */
-    public POIFSFileSystem getFileSystem()
-    {
+    public POIFSFileSystem getFileSystem() {
         return _filesystem;
     }
 
@@ -139,8 +121,7 @@ public class DirectoryNode
      */
     public DocumentInputStream createDocumentInputStream(
             final String documentName)
-            throws IOException
-    {
+            throws IOException {
         return createDocumentInputStream(getEntryCaseInsensitive(documentName));
     }
 
@@ -156,8 +137,7 @@ public class DirectoryNode
      */
     public DocumentInputStream createDocumentInputStream(
             final Entry document)
-            throws IOException
-    {
+            throws IOException {
         if (!document.isDocumentEntry()) {
             throw new IOException("Entry '" + document.getName()
                     + "' is not a DocumentEntry");
@@ -177,10 +157,9 @@ public class DirectoryNode
      * @throws IOException if the document can't be created
      */
     DocumentEntry createDocument(final POIFSDocument document)
-            throws IOException
-    {
+            throws IOException {
         DocumentProperty property = document.getDocumentProperty();
-        DocumentNode     rval     = new DocumentNode(property, this);
+        DocumentNode rval = new DocumentNode(property, this);
 
         (( DirectoryProperty ) getProperty()).addChild(property);
         _filesystem.addDocument(document);
@@ -199,17 +178,14 @@ public class DirectoryNode
      *
      * @return true if the operation succeeded, else false
      */
-    boolean changeName(final String oldName, final String newName)
-    {
-        boolean   rval  = false;
+    boolean changeName(final String oldName, final String newName) {
+        boolean rval = false;
         EntryNode child = ( EntryNode ) _byUCName.get(oldName.toUpperCase(Locale.ROOT));
 
-        if (child != null)
-        {
+        if (child != null) {
             rval = (( DirectoryProperty ) getProperty())
                     .changeName(child.getProperty(), newName);
-            if (rval)
-            {
+            if (rval) {
                 _byname.remove(oldName);
                 _byname.put(child.getProperty().getName(), child);
                 _byUCName.remove(oldName.toUpperCase(Locale.ROOT));
@@ -227,14 +203,12 @@ public class DirectoryNode
      * @return true if the entry was deleted, else false
      */
 
-    boolean deleteEntry(final EntryNode entry)
-    {
+    boolean deleteEntry(final EntryNode entry) {
         boolean rval =
                 (( DirectoryProperty ) getProperty())
                         .deleteChild(entry.getProperty());
 
-        if (rval)
-        {
+        if (rval) {
             _entries.remove(entry);
             _byname.remove(entry.getName());
             _byUCName.remove(entry.getName().toUpperCase(Locale.ROOT));
@@ -263,8 +237,7 @@ public class DirectoryNode
      */
 
     @Override
-    public Iterator<Entry> getEntries()
-    {
+    public Iterator<Entry> getEntries() {
         return _entries.iterator();
     }
 
@@ -278,8 +251,7 @@ public class DirectoryNode
      *         DirectoryEntry is empty)
      */
     @Override
-    public Set<String> getEntryNames()
-    {
+    public Set<String> getEntryNames() {
         return _byname.keySet();
     }
 
@@ -290,8 +262,7 @@ public class DirectoryNode
      */
 
     @Override
-    public boolean isEmpty()
-    {
+    public boolean isEmpty() {
         return _entries.isEmpty();
     }
 
@@ -304,32 +275,29 @@ public class DirectoryNode
      */
 
     @Override
-    public int getEntryCount()
-    {
+    public int getEntryCount() {
         return _entries.size();
     }
 
     /**
      * Checks for a specific entry in a case-sensitive way.
      *
-     * @param name
+     * @param name the name of the Entry to check
      * @return whether or not an entry exists for that name (case-sensitive)
      */
     @Override
-    public boolean hasEntry(String name )
-    {
+    public boolean hasEntry(String name ) {
         return name != null && _byname.containsKey(name);
     }
 
     /**
      * Checks for a specific entry in a case-insensitive way.
      *
-     * @param name
+     * @param name the name of the Entry to check
      * @return whether or not an entry exists for that name (case-insensitive)
      */
     @Override
-    public boolean hasEntryCaseInsensitive(String name )
-    {
+    public boolean hasEntryCaseInsensitive(String name ) {
         return name != null && _byUCName.containsKey(name.toUpperCase(Locale.ROOT));
     }
 
@@ -351,6 +319,7 @@ public class DirectoryNode
         if (name != null) {
             rval = _byname.get(name);
         }
+
         if (rval == null) {
             // throw more useful exceptions for known wrong file-extensions
             if(_byname.containsKey("Workbook")) {
@@ -386,6 +355,7 @@ public class DirectoryNode
         if (name != null) {
             rval = _byUCName.get(name.toUpperCase(Locale.ROOT));
         }
+
         if (rval == null) {
             // throw more useful exceptions for known wrong file-extensions
             if(_byname.containsKey("Workbook")) {
@@ -414,12 +384,9 @@ public class DirectoryNode
      *
      * @throws IOException if the document can't be created
      */
-
     @Override
     public DocumentEntry createDocument(final String name,
-                                        final InputStream stream)
-            throws IOException
-    {
+                                        final InputStream stream) throws IOException {
         return createDocument(new POIFSDocument(name, _filesystem, stream));
     }
 
@@ -434,12 +401,9 @@ public class DirectoryNode
      *
      * @throws IOException if the document can't be created
      */
-
     @Override
     public DocumentEntry createDocument(final String name, final int size,
-                                        final POIFSWriterListener writer)
-            throws IOException
-    {
+                                        final POIFSWriterListener writer) throws IOException {
         return createDocument(new POIFSDocument(name, size, _filesystem, writer));
     }
 
@@ -452,11 +416,8 @@ public class DirectoryNode
      *
      * @throws IOException if the directory can't be created
      */
-
     @Override
-    public DirectoryEntry createDirectory(final String name)
-            throws IOException
-    {
+    public DirectoryEntry createDirectory(final String name) throws IOException {
         DirectoryProperty property = new DirectoryProperty(name);
 
         DirectoryNode rval = new DirectoryNode(property, _filesystem, this);
@@ -482,9 +443,7 @@ public class DirectoryNode
      */
     @SuppressWarnings("WeakerAccess")
     public DocumentEntry createOrUpdateDocument(final String name,
-                                                final InputStream stream)
-            throws IOException
-    {
+                                                final InputStream stream) throws IOException {
         if (! hasEntryCaseInsensitive(name)) {
             return createDocument(name, stream);
         } else {
@@ -501,8 +460,7 @@ public class DirectoryNode
      * @return storage Class ID
      */
     @Override
-    public ClassID getStorageClsid()
-    {
+    public ClassID getStorageClsid() {
         return getProperty().getStorageClsid();
     }
 
@@ -512,8 +470,7 @@ public class DirectoryNode
      * @param clsidStorage storage Class ID
      */
     @Override
-    public void setStorageClsid(ClassID clsidStorage)
-    {
+    public void setStorageClsid(ClassID clsidStorage) {
         getProperty().setStorageClsid(clsidStorage);
     }
 
@@ -527,8 +484,7 @@ public class DirectoryNode
      */
 
     @Override
-    public boolean isDirectoryEntry()
-    {
+    public boolean isDirectoryEntry() {
         return true;
     }
 
@@ -544,9 +500,7 @@ public class DirectoryNode
      */
 
     @Override
-    protected boolean isDeleteOK()
-    {
-
+    protected boolean isDeleteOK() {
         // if this directory is empty, we can delete it
         return isEmpty();
     }
@@ -562,8 +516,7 @@ public class DirectoryNode
      */
 
     @Override
-    public Object [] getViewableArray()
-    {
+    public Object [] getViewableArray() {
         return new Object[ 0 ];
     }
 
@@ -592,8 +545,7 @@ public class DirectoryNode
      */
 
     @Override
-    public boolean preferArray()
-    {
+    public boolean preferArray() {
         return false;
     }
 
@@ -605,11 +557,12 @@ public class DirectoryNode
      */
 
     @Override
-    public String getShortDescription()
-    {
+    public String getShortDescription() {
         return getName();
     }
 
+    /* **********  END  begin implementation of POIFSViewable ********** */
+
     /**
      * Returns an Iterator over all the entries
      */
@@ -627,7 +580,4 @@ public class DirectoryNode
     public Spliterator<Entry> spliterator() {
         return _entries.spliterator();
     }
-
-    /* **********  END  begin implementation of POIFSViewable ********** */
-}   // end public class DirectoryNode
-
+}
diff --git a/poi/src/main/java/org/apache/poi/ss/formula/DataValidationEvaluator.java b/poi/src/main/java/org/apache/poi/ss/formula/DataValidationEvaluator.java
index dcd98bb1dc..b2e4bc1e06 100644
--- a/poi/src/main/java/org/apache/poi/ss/formula/DataValidationEvaluator.java
+++ b/poi/src/main/java/org/apache/poi/ss/formula/DataValidationEvaluator.java
@@ -47,20 +47,20 @@ import org.apache.poi.util.StringUtil;
 /**
  * Evaluates Data Validation constraints.<p>
  *
- * For performance reasons, this class keeps a cache of all previously retrieved {@link DataValidation} instances.  
- * Be sure to call {@link #clearAllCachedValues()} if any workbook validation definitions are 
+ * For performance reasons, this class keeps a cache of all previously retrieved {@link DataValidation} instances.
+ * Be sure to call {@link #clearAllCachedValues()} if any workbook validation definitions are
  * added, modified, or deleted.
  * <p>
  * Changing cell values should be fine, as long as the corresponding {@link WorkbookEvaluator#clearAllCachedResultValues()}
  * is called as well.
- * 
+ *
  */
 public class DataValidationEvaluator {
 
     /**
      * Expensive to compute, so cache them as they are retrieved.
      * <p>
-     * Sheets don't implement equals, and since its an interface, 
+     * Sheets don't implement equals, and since its an interface,
      * there's no guarantee instances won't be recreated on the fly by some implementation.
      * So we use sheet name.
      */
@@ -79,14 +79,14 @@ public class DataValidationEvaluator {
         this.workbook = wb;
         this.workbookEvaluator = provider._getWorkbookEvaluator();
     }
-    
+
     /**
      * @return evaluator
      */
     protected WorkbookEvaluator getWorkbookEvaluator() {
         return workbookEvaluator;
     }
-    
+
     /**
      * Call this whenever validation structures change,
      * so future results stay in sync with the Workbook state.
@@ -94,7 +94,7 @@ public class DataValidationEvaluator {
     public void clearAllCachedValues() {
         validations.clear();
     }
-    
+
     /**
      * Lazy load validations by sheet, since reading the CT* types is expensive
      *
@@ -109,14 +109,14 @@ public class DataValidationEvaluator {
         }
         return dvs;
     }
-    
+
     /**
      * Finds and returns the {@link DataValidation} for the cell, if there is
      * one. Lookup is based on the first match from
      * {@link DataValidation#getRegions()} for the cell's sheet. DataValidation
      * regions must be in the same sheet as the DataValidation. Allowed values
      * expressions may reference other sheets, however.
-     * 
+     *
      * @param cell reference to check - use this in case the cell does not actually exist yet
      * @return the DataValidation applicable to the given cell, or null if no
      *         validation applies
@@ -132,7 +132,7 @@ public class DataValidationEvaluator {
      * {@link DataValidation#getRegions()} for the cell's sheet. DataValidation
      * regions must be in the same sheet as the DataValidation. Allowed values
      * expressions may reference other sheets, however.
-     * 
+     *
      * @param cell reference to check
      * @return the DataValidationContext applicable to the given cell, or null if no
      *         validation applies
@@ -166,7 +166,7 @@ public class DataValidationEvaluator {
      * This method could throw an exception if the validation type is not LIST,
      * but since this method is mostly useful in UI contexts, null seems the
      * easier path.
-     * 
+     *
      * @param cell reference to check - use this in case the cell does not actually exist yet
      * @return returns an unmodifiable {@link List} of {@link ValueEval}s if applicable, or
      *         null
@@ -175,7 +175,7 @@ public class DataValidationEvaluator {
         DataValidationContext context = getValidationContextForCell(cell);
 
         if (context == null) return null;
-        
+
         return getValidationValuesForConstraint(context);
     }
 
@@ -186,11 +186,11 @@ public class DataValidationEvaluator {
     protected static List<ValueEval> getValidationValuesForConstraint(DataValidationContext context) {
         final DataValidationConstraint val = context.getValidation().getValidationConstraint();
         if (val.getValidationType() != ValidationType.LIST) return null;
-        
+
         String formula = val.getFormula1();
-        
+
         final List<ValueEval> values = new ArrayList<>();
-        
+
         if (val.getExplicitListValues() != null && val.getExplicitListValues().length > 0) {
             // assumes parsing interprets the overloaded property right for XSSF
             for (String s : val.getExplicitListValues()) {
@@ -221,7 +221,7 @@ public class DataValidationEvaluator {
      * Note that to properly apply some validations, care must be taken to
      * offset the base validation formula by the relative position of the
      * current cell, or the wrong value is checked.
-     * 
+     *
      * @param cellRef The reference of the cell to evaluate
      * @return true if the cell has no validation or the cell value passes the
      *         defined validation, false if it fails
@@ -230,23 +230,23 @@ public class DataValidationEvaluator {
         final DataValidationContext context = getValidationContextForCell(cellRef);
 
         if (context == null) return true;
-        
+
         final Cell cell = SheetUtil.getCell(workbook.getSheet(cellRef.getSheetName()), cellRef.getRow(), cellRef.getCol());
-        
+
         // now we can validate the cell
-        
+
         // if empty, return not allowed flag
         if (   cell == null
-            || isType(cell, CellType.BLANK)  
-            || (isType(cell,CellType.STRING) 
+            || isType(cell, CellType.BLANK)
+            || (isType(cell,CellType.STRING)
                 && (cell.getStringCellValue() == null || cell.getStringCellValue().isEmpty())
                )
            ) {
             return context.getValidation().getEmptyCellAllowed();
         }
-        
+
         // cell has a value
-        
+
         return ValidationEnum.isValid(cell, context);
     }
 
@@ -259,18 +259,18 @@ public class DataValidationEvaluator {
     */
     public static boolean isType(Cell cell, CellType type) {
         final CellType cellType = cell.getCellType();
-        return cellType == type 
-              || (cellType == CellType.FORMULA 
+        return cellType == type
+              || (cellType == CellType.FORMULA
                   && cell.getCachedFormulaResultType() == type
                  );
     }
-   
+
 
     /**
      * Not calling it ValidationType to avoid confusion for now with DataValidationConstraint.ValidationType.
      * Definition order matches OOXML type ID indexes
      */
-    public static enum ValidationEnum {
+    public enum ValidationEnum {
         ANY {
             public boolean isValidValue(Cell cell, DataValidationContext context) {
                 return true;
@@ -291,11 +291,11 @@ public class DataValidationEvaluator {
             public boolean isValidValue(Cell cell, DataValidationContext context) {
                 final List<ValueEval> valueList = getValidationValuesForConstraint(context);
                 if (valueList == null) return true; // special case
-                
+
                 // compare cell value to each item
                 for (ValueEval listVal : valueList) {
                     ValueEval comp = listVal instanceof RefEval ? ((RefEval) listVal).getInnerValueEval(context.getSheetIndex()) : listVal;
-                    
+
                     // any value is valid if the list contains a blank value per Excel help
                     if (comp instanceof BlankEval) return true;
                     if (comp instanceof ErrorEval) continue; // nothing to check
@@ -310,7 +310,7 @@ public class DataValidationEvaluator {
                         // could this have trouble with double precision/rounding errors and date/time values?
                         // do we need to allow a "close enough" double fractional range?
                         // I see 17 digits after the decimal separator in XSSF files, and for time values,
-                        // there are sometimes discrepancies in the final decimal place.  
+                        // there are sometimes discrepancies in the final decimal place.
                         // I don't have a validation test case yet though. - GW
                         if (isType(cell, CellType.NUMERIC) && ((NumberEval) comp).getNumberValue() == cell.getNumericCellValue()) {
                             return true;
@@ -319,7 +319,7 @@ public class DataValidationEvaluator {
                         }
                     }
                     if (comp instanceof StringEval) {
-                        // interestingly, in testing, a validation value of the string "TRUE" or "true" 
+                        // interestingly, in testing, a validation value of the string "TRUE" or "true"
                         // did not match a boolean cell value of TRUE - so apparently cell type matters
                         // also, Excel validation is case insensitive - "true" is valid for the list value "TRUE"
                         if (isType(cell, CellType.STRING) && ((StringEval) comp).getStringValue().equalsIgnoreCase(cell.getStringCellValue())) {
@@ -368,16 +368,16 @@ public class DataValidationEvaluator {
             }
         },
         ;
-        
+
         public boolean isValidValue(Cell cell, DataValidationContext context) {
             return isValidNumericCell(cell, context);
         }
-        
+
         /**
          * Uses the cell value, which may be the cached formula result value.
          * We won't re-evaluate cells here.  This validation would be after the cell value was updated externally.
-         * Excel allows invalid values through methods like copy/paste, and only validates them when the user 
-         * interactively edits the cell.   
+         * Excel allows invalid values through methods like copy/paste, and only validates them when the user
+         * interactively edits the cell.
          * @return if the cell is a valid numeric cell for the validation or not
          */
         protected boolean isValidNumericCell(Cell cell, DataValidationContext context) {
@@ -394,12 +394,12 @@ public class DataValidationEvaluator {
             try {
                 Double t1 = evalOrConstant(context.getFormula1(), context);
                 // per Excel, a blank value for a numeric validation constraint formula validates true
-                if (t1 == null) return true; 
+                if (t1 == null) return true;
                 Double t2 = null;
                 if (context.getOperator() == OperatorType.BETWEEN || context.getOperator() == OperatorType.NOT_BETWEEN) {
                     t2 = evalOrConstant(context.getFormula2(), context);
                     // per Excel, a blank value for a numeric validation constraint formula validates true
-                    if (t2 == null) return true; 
+                    if (t2 == null) return true;
                 }
                 return OperatorEnum.values()[context.getOperator()].isValid(value, t1, t2);
             } catch (NumberFormatException e) {
@@ -407,7 +407,7 @@ public class DataValidationEvaluator {
                 return false;
             }
         }
-        
+
         /**
          * Evaluate a numeric formula value as either a constant or numeric expression.
          * Note that Excel treats validations with constraint formulas that evaluate to null as valid,
@@ -435,12 +435,12 @@ public class DataValidationEvaluator {
             if (eval instanceof StringEval) {
                 final String value = ((StringEval) eval).getStringValue();
                 if (StringUtil.isBlank(value)) return null;
-                // try to parse the cell value as a double and return it 
+                // try to parse the cell value as a double and return it
                 return Double.valueOf(value);
             }
             throw new NumberFormatException("Formula '" + formula + "' evaluates to something other than a number");
         }
-        
+
         /**
          * Validates against the type defined in context, as an index of the enum values array.
          * @param cell Cell to check validity of
@@ -451,14 +451,14 @@ public class DataValidationEvaluator {
         public static boolean isValid(Cell cell, DataValidationContext context) {
             return values()[context.getValidation().getValidationConstraint().getValidationType()].isValidValue(cell, context);
         }
-        
+
     }
-    
+
     /**
      * Not calling it OperatorType to avoid confusion for now with DataValidationConstraint.OperatorType.
      * Definition order matches OOXML type ID indexes
      */
-    public static enum OperatorEnum {
+    public enum OperatorEnum {
         BETWEEN {
             public boolean isValid(Double cellValue, Double v1, Double v2) {
                 return cellValue.compareTo(v1) >= 0 && cellValue.compareTo(v2) <= 0;
@@ -500,9 +500,9 @@ public class DataValidationEvaluator {
             }
         },
         ;
-        
+
         public static final OperatorEnum IGNORED = BETWEEN;
-        
+
         /**
          * Evaluates comparison using operator instance rules
          * @param cellValue won't be null, assumption is previous checks handled that
@@ -512,7 +512,7 @@ public class DataValidationEvaluator {
          */
         public abstract boolean isValid(Double cellValue, Double v1, Double v2);
     }
-    
+
     /**
      * This class organizes and encapsulates all the pieces of information related to a single
      * data validation configuration for a single cell.  It cleanly separates the validation region,
@@ -524,7 +524,7 @@ public class DataValidationEvaluator {
         private final DataValidationEvaluator dve;
         private final CellRangeAddressBase region;
         private final CellReference target;
-        
+
         /**
          * Populate the context with the necessary values.
          */
@@ -558,30 +558,30 @@ public class DataValidationEvaluator {
         public CellReference getTarget() {
             return target;
         }
-        
+
         public int getOffsetColumns() {
             return target.getCol() - region.getFirstColumn();
         }
-        
+
         public int getOffsetRows() {
             return target.getRow() - region.getFirstRow();
         }
-        
+
         public int getSheetIndex() {
             return dve.getWorkbookEvaluator().getSheetIndex(target.getSheetName());
         }
-        
+
         public String getFormula1() {
             return dv.getValidationConstraint().getFormula1();
         }
-        
+
         public String getFormula2() {
             return dv.getValidationConstraint().getFormula2();
         }
-        
+
         public int getOperator() {
             return dv.getValidationConstraint().getOperator();
         }
-        
+
     }
 }
diff --git a/poi/src/test/java/org/apache/poi/hssf/record/TestRecordInputStream.java b/poi/src/test/java/org/apache/poi/hssf/record/TestRecordInputStream.java
index 8622230338..7485a9738a 100644
--- a/poi/src/test/java/org/apache/poi/hssf/record/TestRecordInputStream.java
+++ b/poi/src/test/java/org/apache/poi/hssf/record/TestRecordInputStream.java
@@ -20,6 +20,8 @@ package org.apache.poi.hssf.record;
 import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
+import java.io.IOException;
+
 import org.apache.poi.util.HexRead;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.params.ParameterizedTest;
@@ -53,9 +55,8 @@ final class TestRecordInputStream {
             + "1A 59 00 8A 9E 8A " // 3 uncompressed unicode chars
     ;
 
-
     @Test
-    void testChangeOfCompressionFlag_bug25866() {
+    void testChangeOfCompressionFlag_bug25866() throws IOException {
         byte[] changingFlagSimpleData = HexRead.readFromString(""
                 + "AA AA "  // fake SID
                 + "06 00 "  // first rec len 6
@@ -66,10 +67,13 @@ final class TestRecordInputStream {
         // bug 45866 - compressByte in continue records must be 1 while reading unicode LE string
         String actual  = in.readUnicodeLEString(18);
         assertEquals("\u591A\u8A00\u8A9E - Multilingual", actual);
+
+        in.mark(10);
+        in.reset();
     }
 
     @Test
-    void testChangeFromUnCompressedToCompressed() {
+    void testChangeFromUnCompressedToCompressed() throws IOException {
         byte[] changingFlagSimpleData = HexRead.readFromString(""
                 + "AA AA "  // fake SID
                 + "0F 00 "  // first rec len 15
@@ -78,10 +82,13 @@ final class TestRecordInputStream {
         RecordInputStream in = TestcaseRecordInputStream.create(changingFlagSimpleData);
         String actual = in.readCompressedUnicode(18);
         assertEquals("Multilingual - \u591A\u8A00\u8A9E", actual);
+
+        in.mark(10);
+        in.reset();
     }
 
     @Test
-    void testReadString() {
+    void testReadString() throws IOException {
         byte[] changingFlagFullData = HexRead.readFromString(""
                 + "AA AA "  // fake SID
                 + "12 00 "  // first rec len 18 (15 + next 3 bytes)
@@ -92,6 +99,9 @@ final class TestRecordInputStream {
         RecordInputStream in = TestcaseRecordInputStream.create(changingFlagFullData);
         String actual = in.readString();
         assertEquals("Multilingual - \u591A\u8A00\u8A9E", actual);
+
+        in.mark(10);
+        in.reset();
     }
 
     @ParameterizedTest
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 7e16d69df6..ceea6b1b88 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
@@ -537,6 +537,7 @@ public abstract class BaseTestWorkbook {
     /**
      * Tests that all the unicode capable string fields can be set, written and then read back
      */
+    @SuppressWarnings("UnnecessaryUnicodeEscape")
     @Test
     protected void unicodeInAll() throws IOException {
         try (Workbook wb1 = _testDataProvider.createWorkbook()) {
@@ -850,7 +851,7 @@ public abstract class BaseTestWorkbook {
             wb.removeSheetAt(0);
             wb.removeSheetAt(2);
 
-            // ensure that sheets are moved up and removed sheets are not found any more
+            // ensure that sheets are moved up and removed sheets are not found anymore
             assertEquals(-1, wb.getSheetIndex(sheet1));
             assertEquals(0, wb.getSheetIndex(sheet2));
             assertEquals(1, wb.getSheetIndex(sheet3));
@@ -936,4 +937,20 @@ public abstract class BaseTestWorkbook {
             );
         }
     }
+
+    @Test
+    void testSheetNameDifferOnlyLowercaseUppercase() throws IOException {
+        try (Workbook wb = _testDataProvider.createWorkbook()) {
+            wb.createSheet("abc");
+            assertEquals(1, wb.getNumberOfSheets());
+
+            assertThrows(IllegalArgumentException.class,
+                    () -> wb.createSheet("ABC"));
+            assertEquals(1, wb.getNumberOfSheets());
+
+            Sheet sheet = wb.getSheet("abc");
+            assertNotNull(sheet);
+            assertEquals("abc", sheet.getSheetName());
+        }
+    }
 }