Sonar fixes

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1884807 13f79535-47bb-0310-9956-ffa450edef68

26 files changed, 123 insertions, 110 deletions

diff --git a/src/java/org/apache/poi/extractor/ExtractorFactory.java b/src/java/org/apache/poi/extractor/ExtractorFactory.java
index 0833535189..b45b5e29e2 100644
--- a/src/java/org/apache/poi/extractor/ExtractorFactory.java
+++ b/src/java/org/apache/poi/extractor/ExtractorFactory.java
@@ -178,6 +178,7 @@ public final class ExtractorFactory {
         return createExtractor(file, getCurrentUserPassword());
     }
 
+    @SuppressWarnings({"java:S2095"})
     public static POITextExtractor createExtractor(File file, String password) throws IOException {
         if (file.length() == 0) {
             throw new EmptyFileException();
@@ -318,6 +319,6 @@ public final class ExtractorFactory {
     }
 
     public static void removeProvider(Class<? extends ExtractorProvider> provider){
-        Singleton.INSTANCE.provider.removeIf(p -> p.getClass().getName().equals(provider.getName()));
+        Singleton.INSTANCE.provider.removeIf(p -> p.getClass().isAssignableFrom(provider));
     }
 }
diff --git a/src/java/org/apache/poi/extractor/MainExtractorFactory.java b/src/java/org/apache/poi/extractor/MainExtractorFactory.java
index 7f8733eecf..d485f864ff 100644
--- a/src/java/org/apache/poi/extractor/MainExtractorFactory.java
+++ b/src/java/org/apache/poi/extractor/MainExtractorFactory.java
@@ -41,6 +41,7 @@ public class MainExtractorFactory implements ExtractorProvider {
         return FileMagic.OLE2 == fm;
     }
 
+    @SuppressWarnings({"java:S2095"})
     @Override
     public POITextExtractor create(File file, String password) throws IOException {
         return create(new POIFSFileSystem(file, true).getRoot(), password);
diff --git a/src/java/org/apache/poi/hssf/dev/ReSave.java b/src/java/org/apache/poi/hssf/dev/ReSave.java
index 7f19888973..2f31eb48d8 100644
--- a/src/java/org/apache/poi/hssf/dev/ReSave.java
+++ b/src/java/org/apache/poi/hssf/dev/ReSave.java
@@ -37,7 +37,6 @@ public class ReSave {
     public static void main(String[] args) throws Exception {
         boolean initDrawing = false;
         boolean saveToMemory = false;
-        ByteArrayOutputStream bos = new ByteArrayOutputStream();
         for(String filename : args) {
             if(filename.equals("-dg")) {
                 initDrawing = true;
@@ -45,11 +44,10 @@ public class ReSave {
                 saveToMemory = true;
             } else {
                 System.out.print("reading " + filename + "...");
-                FileInputStream is = new FileInputStream(filename);
-                HSSFWorkbook wb = new HSSFWorkbook(is);
-                try {
+                try (FileInputStream is = new FileInputStream(filename);
+                     HSSFWorkbook wb = new HSSFWorkbook(is)) {
                     System.out.println("done");
-    
+
                     for(int i = 0; i < wb.getNumberOfSheets(); i++){
                         HSSFSheet sheet = wb.getSheetAt(i);
                         if(initDrawing) {
@@ -57,25 +55,15 @@ public class ReSave {
                         }
                     }
 
-                    OutputStream os;
-                    if (saveToMemory) {
-                        bos.reset();
-                        os = bos;
-                    } else {
-                        String outputFile = filename.replace(".xls", "-saved.xls");
+                    String outputFile = filename.replace(".xls", "-saved.xls");
+                    if (!saveToMemory) {
                         System.out.print("saving to " + outputFile + "...");
-                        os = new FileOutputStream(outputFile);
                     }
-                    
-                    try {
+
+                    try (OutputStream os = saveToMemory ? new ByteArrayOutputStream() : new FileOutputStream(outputFile)) {
                         wb.write(os);
-                    } finally {
-                        os.close();
                     }
                     System.out.println("done");
-                } finally {
-                    wb.close();
-                    is.close();
                 }
             }
         }
diff --git a/src/java/org/apache/poi/hssf/model/InternalWorkbook.java b/src/java/org/apache/poi/hssf/model/InternalWorkbook.java
index 8ddb368e0a..e1d4f85718 100644
--- a/src/java/org/apache/poi/hssf/model/InternalWorkbook.java
+++ b/src/java/org/apache/poi/hssf/model/InternalWorkbook.java
@@ -1052,7 +1052,7 @@ public final class InternalWorkbook {
         // Can be a few short if new sheets were added
         if(records.getTabpos() > 0) {
             TabIdRecord tir = ( TabIdRecord ) records.get(records.getTabpos());
-            if(tir._tabids.length < boundsheets.size()) {
+            if(tir.getTabIdSize() < boundsheets.size()) {
                 fixTabIdRecord();
             }
         }
diff --git a/src/java/org/apache/poi/hssf/record/GridsetRecord.java b/src/java/org/apache/poi/hssf/record/GridsetRecord.java
index d5f705071f..b5cfd92055 100644
--- a/src/java/org/apache/poi/hssf/record/GridsetRecord.java
+++ b/src/java/org/apache/poi/hssf/record/GridsetRecord.java
@@ -30,7 +30,7 @@ import org.apache.poi.util.LittleEndianOutput;
  */
 public final class GridsetRecord extends StandardRecord {
     public static final short sid = 0x82;
-    public short              field_1_gridset_flag;
+    private short field_1_gridset_flag;
 
     public GridsetRecord() {}
 
diff --git a/src/java/org/apache/poi/hssf/record/PageBreakRecord.java b/src/java/org/apache/poi/hssf/record/PageBreakRecord.java
index 99369d9ae3..402c04d02c 100644
--- a/src/java/org/apache/poi/hssf/record/PageBreakRecord.java
+++ b/src/java/org/apache/poi/hssf/record/PageBreakRecord.java
@@ -53,9 +53,9 @@ public abstract class PageBreakRecord extends StandardRecord {
     public static final class Break implements GenericRecord {
 
         public static final int ENCODED_SIZE = 6;
-        public int main;
-        public int subFrom;
-        public int subTo;
+        private int main;
+        private int subFrom;
+        private int subTo;
 
         public Break(Break other) {
             main = other.main;
@@ -75,6 +75,18 @@ public abstract class PageBreakRecord extends StandardRecord {
             subTo = in.readUShort();
         }
 
+        public int getMain() {
+            return main;
+        }
+
+        public int getSubFrom() {
+            return subFrom;
+        }
+
+        public int getSubTo() {
+            return subTo;
+        }
+
         public void serialize(LittleEndianOutput out) {
             out.writeShort(main + 1);
             out.writeShort(subFrom);
diff --git a/src/java/org/apache/poi/hssf/record/PrecisionRecord.java b/src/java/org/apache/poi/hssf/record/PrecisionRecord.java
index 49cbf31de5..27471b935f 100644
--- a/src/java/org/apache/poi/hssf/record/PrecisionRecord.java
+++ b/src/java/org/apache/poi/hssf/record/PrecisionRecord.java
@@ -32,7 +32,7 @@ import org.apache.poi.util.LittleEndianOutput;
 public final class PrecisionRecord extends StandardRecord {
     public static final short sid = 0xE;
 
-    public short field_1_precision;
+    private short field_1_precision;
 
     public PrecisionRecord() {}
 
diff --git a/src/java/org/apache/poi/hssf/record/TabIdRecord.java b/src/java/org/apache/poi/hssf/record/TabIdRecord.java
index 2fc905bb9e..c76a396bd7 100644
--- a/src/java/org/apache/poi/hssf/record/TabIdRecord.java
+++ b/src/java/org/apache/poi/hssf/record/TabIdRecord.java
@@ -30,7 +30,7 @@ public final class TabIdRecord extends StandardRecord {
     public static final short sid = 0x013D;
     private static final short[] EMPTY_SHORT_ARRAY = { };
 
-    public short[] _tabids;
+    private short[] _tabids;
 
     public TabIdRecord() {
         _tabids = EMPTY_SHORT_ARRAY;
@@ -63,6 +63,14 @@ public final class TabIdRecord extends StandardRecord {
         }
     }
 
+    public int getTabIdSize() {
+        return _tabids.length;
+    }
+
+    public short getTabIdAt(int index) {
+        return _tabids[index];
+    }
+
     protected int getDataSize() {
         return _tabids.length * 2;
     }
diff --git a/src/java/org/apache/poi/hssf/record/aggregates/PageSettingsBlock.java b/src/java/org/apache/poi/hssf/record/aggregates/PageSettingsBlock.java
index 78b93a0e41..c8d931f349 100644
--- a/src/java/org/apache/poi/hssf/record/aggregates/PageSettingsBlock.java
+++ b/src/java/org/apache/poi/hssf/record/aggregates/PageSettingsBlock.java
@@ -121,7 +121,7 @@ public final class PageSettingsBlock extends RecordAggregate {
 
     /**
      * @param sid the record sid
-     * 
+     *
      * @return <code>true</code> if the specified Record sid is one belonging to the
      * 'Page Settings Block'.
      */
@@ -486,7 +486,7 @@ public final class PageSettingsBlock extends RecordAggregate {
         while(iterator.hasNext())
         {
             PageBreakRecord.Break breakItem = iterator.next();
-            int breakLocation = breakItem.main;
+            int breakLocation = breakItem.getMain();
             boolean inStart = (breakLocation >= start);
             boolean inEnd = (breakLocation <= stop);
             if(inStart && inEnd) {
@@ -497,8 +497,8 @@ public final class PageSettingsBlock extends RecordAggregate {
         iterator = shiftedBreak.iterator();
         while (iterator.hasNext()) {
             PageBreakRecord.Break breakItem = iterator.next();
-            breaks.removeBreak(breakItem.main);
-            breaks.addBreak((short)(breakItem.main+count), breakItem.subFrom, breakItem.subTo);
+            breaks.removeBreak(breakItem.getMain());
+            breaks.addBreak((short)(breakItem.getMain()+count), breakItem.getSubFrom(), breakItem.getSubTo());
         }
     }
 
@@ -526,9 +526,9 @@ public final class PageSettingsBlock extends RecordAggregate {
 
     /**
      * Queries if the specified row has a page break
-     * 
+     *
      * @param row the row to check for
-     * 
+     *
      * @return true if the specified row has a page break
      */
     public boolean isRowBroken(int row) {
@@ -538,7 +538,7 @@ public final class PageSettingsBlock extends RecordAggregate {
 
     /**
      * Queries if the specified column has a page break
-     * 
+     *
      * @param column the column to check for
      *
      * @return <code>true</code> if the specified column has a page break
@@ -606,7 +606,7 @@ public final class PageSettingsBlock extends RecordAggregate {
     /**
      * HEADERFOOTER is new in 2007.  Some apps seem to have scattered this record long after
      * the {@link PageSettingsBlock} where it belongs.
-     * 
+     *
      * @param rec the HeaderFooterRecord to set
      */
     public void addLateHeaderFooter(HeaderFooterRecord rec) {
@@ -623,10 +623,10 @@ public final class PageSettingsBlock extends RecordAggregate {
      * This method reads PageSettingsBlock records from the supplied RecordStream until the first
      * non-PageSettingsBlock record is encountered.  As each record is read, it is incorporated
      * into this PageSettingsBlock.<p>
-     * 
+     *
      * The latest Excel version seems to write the PageSettingsBlock uninterrupted. However there
      * are several examples (that Excel reads OK) where these records are not written together:
-     * 
+     *
      * <ul>
      * <li><b>HEADER_FOOTER(0x089C) after WINDOW2</b> - This record is new in 2007.  Some apps
      * seem to have scattered this record long after the PageSettingsBlock where it belongs
@@ -635,7 +635,7 @@ public final class PageSettingsBlock extends RecordAggregate {
      * This happens in the test sample file "NoGutsRecords.xls" and "WORKBOOK_in_capitals.xls"</li>
      * <li><b>Margins after DIMENSION</b> - All of PSB should be before DIMENSION. (Bug-47199)</li>
      * </ul>
-     * 
+     *
      * These were probably written by other applications (or earlier versions of Excel). It was
      * decided to not write specific code for detecting each of these cases.  POI now tolerates
      * PageSettingsBlock records scattered all over the sheet record stream, and in any order, but
@@ -646,7 +646,7 @@ public final class PageSettingsBlock extends RecordAggregate {
      * were when they were originally read.
      *
      * @param rs the RecordStream to read from
-     * 
+     *
      * @throws  org.apache.poi.util.RecordFormatException if any PSB record encountered has the same type (sid) as
      * a record that is already part of this PageSettingsBlock
      */
diff --git a/src/java/org/apache/poi/hssf/record/common/PhRun.java b/src/java/org/apache/poi/hssf/record/common/PhRun.java
index 2f5a9229da..404efb0bd0 100644
--- a/src/java/org/apache/poi/hssf/record/common/PhRun.java
+++ b/src/java/org/apache/poi/hssf/record/common/PhRun.java
@@ -59,4 +59,14 @@ public class PhRun {
     public int hashCode() {
         return Objects.hash(phoneticTextFirstCharacterOffset, realTextFirstCharacterOffset, realTextLength);
     }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        PhRun phRun = (PhRun) o;
+        return phoneticTextFirstCharacterOffset == phRun.phoneticTextFirstCharacterOffset
+            && realTextFirstCharacterOffset == phRun.realTextFirstCharacterOffset
+            && realTextLength == phRun.realTextLength;
+    }
 }
diff --git a/src/java/org/apache/poi/poifs/common/POIFSConstants.java b/src/java/org/apache/poi/poifs/common/POIFSConstants.java
index 7cacb68fe8..f3804a90be 100644
--- a/src/java/org/apache/poi/poifs/common/POIFSConstants.java
+++ b/src/java/org/apache/poi/poifs/common/POIFSConstants.java
@@ -57,11 +57,4 @@ public interface POIFSConstants
     int END_OF_CHAIN   = -2;
     /** Indicates the sector is not used (0xFFFFFFFF) */
     int UNUSED_BLOCK   = -1;
-
-    /** The first 4 bytes of an OOXML file, used in detection */
-    byte[] OOXML_FILE_HEADER =
-    	new byte[] { 0x50, 0x4b, 0x03, 0x04 };
-    /** The first 5 bytes of a raw XML file, used in detection */
-    byte[] RAW_XML_FILE_HEADER =
-        new byte[] { 0x3c, 0x3f, 0x78, 0x6d, 0x6c };
-}   // end public interface POIFSConstants;
+}
diff --git a/src/java/org/apache/poi/poifs/crypt/agile/AgileDecryptor.java b/src/java/org/apache/poi/poifs/crypt/agile/AgileDecryptor.java
index f8efe0d201..898670eaba 100644
--- a/src/java/org/apache/poi/poifs/crypt/agile/AgileDecryptor.java
+++ b/src/java/org/apache/poi/poifs/crypt/agile/AgileDecryptor.java
@@ -205,6 +205,7 @@ public class AgileDecryptor extends Decryptor {
         }
     }
 
+    @SuppressWarnings({"java:S2095"})
     @Override
     public InputStream getDataStream(DirectoryNode dir) throws IOException, GeneralSecurityException {
         DocumentInputStream dis = dir.createDocumentInputStream(DEFAULT_POIFS_ENTRY);
diff --git a/src/java/org/apache/poi/poifs/crypt/binaryrc4/BinaryRC4Decryptor.java b/src/java/org/apache/poi/poifs/crypt/binaryrc4/BinaryRC4Decryptor.java
index 3aec22e55f..ff14f19ab3 100644
--- a/src/java/org/apache/poi/poifs/crypt/binaryrc4/BinaryRC4Decryptor.java
+++ b/src/java/org/apache/poi/poifs/crypt/binaryrc4/BinaryRC4Decryptor.java
@@ -140,7 +140,7 @@ public class BinaryRC4Decryptor extends Decryptor {
     }
 
     @Override
-    @SuppressWarnings("resource")
+    @SuppressWarnings({"java:S2095","resource"})
     public ChunkedCipherInputStream getDataStream(DirectoryNode dir) throws IOException,
             GeneralSecurityException {
         DocumentInputStream dis = dir.createDocumentInputStream(DEFAULT_POIFS_ENTRY);
diff --git a/src/java/org/apache/poi/poifs/filesystem/FileMagic.java b/src/java/org/apache/poi/poifs/filesystem/FileMagic.java
index 501db481a6..60667f88a5 100644
--- a/src/java/org/apache/poi/poifs/filesystem/FileMagic.java
+++ b/src/java/org/apache/poi/poifs/filesystem/FileMagic.java
@@ -17,9 +17,6 @@
 
 package org.apache.poi.poifs.filesystem;
 
-import static org.apache.poi.poifs.common.POIFSConstants.OOXML_FILE_HEADER;
-import static org.apache.poi.poifs.common.POIFSConstants.RAW_XML_FILE_HEADER;
-
 import java.io.BufferedInputStream;
 import java.io.File;
 import java.io.FileInputStream;
@@ -39,24 +36,24 @@ import org.apache.poi.util.LocaleUtil;
 public enum FileMagic {
     /** OLE2 / BIFF8+ stream used for Office 97 and higher documents */
     OLE2(HeaderBlockConstants._signature),
-    /** OOXML / ZIP stream */
-    OOXML(OOXML_FILE_HEADER),
-    /** XML file */
-    XML(RAW_XML_FILE_HEADER),
+    /** OOXML / ZIP stream - The first 4 bytes of an OOXML file, used in detection */
+    OOXML(0x50, 0x4b, 0x03, 0x04),
+    /** XML file - The first 5 bytes of a raw XML file, used in detection */
+    XML(0x3c, 0x3f, 0x78, 0x6d, 0x6c),
     /** BIFF2 raw stream - for Excel 2 */
-    BIFF2(new byte[]{
+    BIFF2(
         0x09, 0x00, // sid=0x0009
         0x04, 0x00, // size=0x0004
         0x00, 0x00, // unused
         '?', 0x00  // '?' = multiple values
-    }),
+    ),
     /** BIFF3 raw stream - for Excel 3 */
-    BIFF3(new byte[]{
+    BIFF3(
         0x09, 0x02, // sid=0x0209
         0x06, 0x00, // size=0x0006
         0x00, 0x00, // unused
         '?', 0x00  // '?' = multiple values
-    }),
+    ),
     /** BIFF4 raw stream - for Excel 4 */
     BIFF4(new byte[]{
         0x09, 0x04, // sid=0x0409
@@ -81,7 +78,7 @@ public enum FileMagic {
     HTML("<!DOCTYP",
          "<html","\n\r<html","\r\n<html","\r<html","\n<html",
          "<HTML","\r\n<HTML","\n\r<HTML","\r<HTML","\n<HTML"),
-    WORD2(new byte[]{ (byte)0xdb, (byte)0xa5, 0x2d, 0x00}),
+    WORD2(0xdb, 0xa5, 0x2d, 0x00),
     /** JPEG image */
     JPEG(
         new byte[]{ (byte)0xFF, (byte)0xD8, (byte)0xFF, (byte)0xDB },
@@ -91,20 +88,18 @@ public enum FileMagic {
     /** GIF image */
     GIF("GIF87a","GIF89a"),
     /** PNG Image */
-    PNG(new byte[]{ (byte)0x89, 'P', 'N', 'G', 0x0D, 0x0A, 0x1A, 0x0A }),
+    PNG(0x89, 'P', 'N', 'G', 0x0D, 0x0A, 0x1A, 0x0A),
     /** TIFF Image */
     TIFF("II*\u0000", "MM\u0000*" ),
     /** WMF image with a placeable header */
-    WMF(new byte[]{ (byte)0xD7, (byte)0xCD, (byte)0xC6, (byte)0x9A }),
+    WMF(0xD7, 0xCD, 0xC6, 0x9A),
     /** EMF image */
-    EMF(new byte[]{
-        1, 0, 0, 0,
+    EMF(1, 0, 0, 0,
         '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?',
         '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?',
-        ' ', 'E', 'M', 'F'
-    }),
+        ' ', 'E', 'M', 'F'),
     /** BMP image */
-    BMP(new byte[]{'B','M'}),
+    BMP('B','M'),
     // keep UNKNOWN always as last enum!
     /** UNKNOWN magic */
     UNKNOWN(new byte[0]);
@@ -119,6 +114,14 @@ public enum FileMagic {
         LittleEndian.putLong(this.magic[0], 0, magic);
     }
 
+    FileMagic(int... magic) {
+        byte[] one = new byte[magic.length];
+        for (int i=0; i<magic.length; i++) {
+            one[i] = (byte)(magic[i] & 0xFF);
+        }
+        this.magic = new byte[][]{ one };
+    }
+
     FileMagic(byte[]... magic) {
         this.magic = magic;
     }
diff --git a/src/java/org/apache/poi/poifs/filesystem/POIFSFileSystem.java b/src/java/org/apache/poi/poifs/filesystem/POIFSFileSystem.java
index 22577980a3..20fc398e27 100644
--- a/src/java/org/apache/poi/poifs/filesystem/POIFSFileSystem.java
+++ b/src/java/org/apache/poi/poifs/filesystem/POIFSFileSystem.java
@@ -204,6 +204,7 @@ public class POIFSFileSystem extends BlockStore
         this(channel, null, readOnly, false);
     }
 
+    @SuppressWarnings("java:S2095")
     private POIFSFileSystem(FileChannel channel, File srcFile, boolean readOnly, boolean closeChannelOnError)
             throws IOException {
         this(false);
diff --git a/src/java/org/apache/poi/sl/draw/DrawTextParagraph.java b/src/java/org/apache/poi/sl/draw/DrawTextParagraph.java
index b3d70fff26..e047b3468d 100644
--- a/src/java/org/apache/poi/sl/draw/DrawTextParagraph.java
+++ b/src/java/org/apache/poi/sl/draw/DrawTextParagraph.java
@@ -177,7 +177,7 @@ public class DrawTextParagraph implements Drawable {
                 penY -= line.getLayout().getAscent();
             }
 
-            penX = x + (isHSLF ? leftMargin : leftMargin);
+            penX = x + leftMargin;
             if (lastLine == null) {
                 if (!isEmptyParagraph()) {
                     // TODO: find out character style for empty, but bulleted/numbered lines
diff --git a/src/java/org/apache/poi/sl/usermodel/SlideShowFactory.java b/src/java/org/apache/poi/sl/usermodel/SlideShowFactory.java
index a69efaf8f8..cb0607de61 100644
--- a/src/java/org/apache/poi/sl/usermodel/SlideShowFactory.java
+++ b/src/java/org/apache/poi/sl/usermodel/SlideShowFactory.java
@@ -298,7 +298,7 @@ public final class SlideShowFactory {
         Singleton.INSTANCE.provider.add(provider);
     }
 
-    public static void removeProvider(Class<? extends SlideShowProvider> provider){
-        Singleton.INSTANCE.provider.removeIf(p -> p.getClass().getName().equals(provider.getName()));
+    public static void removeProvider(Class<? extends SlideShowProvider<?,?>> provider){
+        Singleton.INSTANCE.provider.removeIf(p -> p.getClass().isAssignableFrom(provider));
     }
 }
diff --git a/src/java/org/apache/poi/ss/formula/SheetIdentifier.java b/src/java/org/apache/poi/ss/formula/SheetIdentifier.java
index 51c0852b30..69f6f99501 100644
--- a/src/java/org/apache/poi/ss/formula/SheetIdentifier.java
+++ b/src/java/org/apache/poi/ss/formula/SheetIdentifier.java
@@ -18,8 +18,8 @@
 package org.apache.poi.ss.formula;
 
 public class SheetIdentifier {
-    public String _bookName;
-    public NameIdentifier _sheetIdentifier;
+    private final String _bookName;
+    private final NameIdentifier _sheetIdentifier;
 
     public SheetIdentifier(String bookName, NameIdentifier sheetIdentifier) {
         _bookName = bookName;
diff --git a/src/java/org/apache/poi/ss/formula/SheetRangeIdentifier.java b/src/java/org/apache/poi/ss/formula/SheetRangeIdentifier.java
index 8cb5b3201a..88c91991b9 100644
--- a/src/java/org/apache/poi/ss/formula/SheetRangeIdentifier.java
+++ b/src/java/org/apache/poi/ss/formula/SheetRangeIdentifier.java
@@ -18,7 +18,7 @@
 package org.apache.poi.ss.formula;
 
 public class SheetRangeIdentifier extends SheetIdentifier {
-    public NameIdentifier _lastSheetIdentifier;
+    private final NameIdentifier _lastSheetIdentifier;
 
     public SheetRangeIdentifier(String bookName, NameIdentifier firstSheetIdentifier, NameIdentifier lastSheetIdentifier) {
         super(bookName, firstSheetIdentifier);
diff --git a/src/java/org/apache/poi/ss/formula/atp/YearFracCalculator.java b/src/java/org/apache/poi/ss/formula/atp/YearFracCalculator.java
index 77ed481481..aba00e7f6b 100644
--- a/src/java/org/apache/poi/ss/formula/atp/YearFracCalculator.java
+++ b/src/java/org/apache/poi/ss/formula/atp/YearFracCalculator.java
@@ -324,7 +324,7 @@ final class YearFracCalculator {
 		/** day of month */
 		public final int day;
 		/** milliseconds since 1970 */
-		public long tsMilliseconds;
+		public final long tsMilliseconds;
 
 		public SimpleDate(Calendar cal) {
 			year = cal.get(Calendar.YEAR);
diff --git a/src/java/org/apache/poi/ss/formula/functions/LinearRegressionFunction.java b/src/java/org/apache/poi/ss/formula/functions/LinearRegressionFunction.java
index aee79ab274..513daa3a1b 100644
--- a/src/java/org/apache/poi/ss/formula/functions/LinearRegressionFunction.java
+++ b/src/java/org/apache/poi/ss/formula/functions/LinearRegressionFunction.java
@@ -107,7 +107,7 @@ public final class LinearRegressionFunction extends Fixed2ArgFunction {
 	}
 
 	public enum FUNCTION {INTERCEPT, SLOPE}
-	public FUNCTION function;
+	private final FUNCTION function;
 
 	public LinearRegressionFunction(FUNCTION function) {
 		this.function = function;
diff --git a/src/java/org/apache/poi/ss/formula/functions/Trend.java b/src/java/org/apache/poi/ss/formula/functions/Trend.java
index 2a1227e2db..62eb545670 100644
--- a/src/java/org/apache/poi/ss/formula/functions/Trend.java
+++ b/src/java/org/apache/poi/ss/formula/functions/Trend.java
@@ -60,11 +60,10 @@ import org.apache.poi.ss.formula.eval.ValueEval;
  */
 
 public final class Trend implements Function {
-    MatrixFunction.MutableValueCollector collector = new MatrixFunction.MutableValueCollector(false, false);
     private static final class TrendResults {
-        public double[] vals;
-        public int resultWidth;
-        public int resultHeight;
+        private final double[] vals;
+        private final int resultWidth;
+        private final int resultHeight;
 
         public TrendResults(double[] vals, int resultWidth, int resultHeight) {
             this.vals = vals;
@@ -149,7 +148,7 @@ public final class Trend implements Function {
         }
         double[] oneD = new double[twoD.length * twoD[0].length];
         for (int i = 0; i < twoD.length; i++) {
-            System.arraycopy(twoD[i], 0, oneD, i * twoD[0].length + 0, twoD[0].length);
+            System.arraycopy(twoD[i], 0, oneD, i * twoD[0].length, twoD[0].length);
         }
         return oneD;
     }
@@ -335,7 +334,7 @@ public final class Trend implements Function {
         if(isAllColumnsSame(x)){
             double[] result = new double[newX.length];
             double avg = Arrays.stream(y).average().orElse(0);
-            for(int i = 0; i < result.length; i++) result[i] = avg;
+            Arrays.fill(result, avg);
             return new TrendResults(result, resultWidth, resultHeight);
         }
 
diff --git a/src/java/org/apache/poi/ss/usermodel/WorkbookFactory.java b/src/java/org/apache/poi/ss/usermodel/WorkbookFactory.java
index b730731f7c..c2b6e6936f 100644
--- a/src/java/org/apache/poi/ss/usermodel/WorkbookFactory.java
+++ b/src/java/org/apache/poi/ss/usermodel/WorkbookFactory.java
@@ -305,6 +305,6 @@ public final class WorkbookFactory {
     }
 
     public static void removeProvider(Class<? extends WorkbookProvider> provider){
-        Singleton.INSTANCE.provider.removeIf(p -> p.getClass().getName().equals(provider.getName()));
+        Singleton.INSTANCE.provider.removeIf(p -> p.getClass().isAssignableFrom(provider));
     }
 }
diff --git a/src/java/org/apache/poi/ss/util/cellwalk/CellWalk.java b/src/java/org/apache/poi/ss/util/cellwalk/CellWalk.java
index 2826cc3323..d26d7a9864 100644
--- a/src/java/org/apache/poi/ss/util/cellwalk/CellWalk.java
+++ b/src/java/org/apache/poi/ss/util/cellwalk/CellWalk.java
@@ -17,6 +17,10 @@
 
 package org.apache.poi.ss.util.cellwalk;
 
+import static org.apache.commons.math3.util.ArithmeticUtils.addAndCheck;
+import static org.apache.commons.math3.util.ArithmeticUtils.mulAndCheck;
+import static org.apache.commons.math3.util.ArithmeticUtils.subAndCheck;
+
 import org.apache.commons.math3.util.ArithmeticUtils;
 import org.apache.poi.ss.usermodel.Cell;
 import org.apache.poi.ss.usermodel.CellType;
@@ -26,13 +30,11 @@ import org.apache.poi.ss.util.CellRangeAddress;
 
 /**
  * Traverse cell range.
- *
- * @author Roman Kashitsyn
  */
 public class CellWalk {
 
-    private Sheet sheet;
-    private CellRangeAddress range;
+    private final Sheet sheet;
+    private final CellRangeAddress range;
     private boolean traverseEmptyCells;
 
 
@@ -74,8 +76,8 @@ public class CellWalk {
         int lastColumn = range.getLastColumn();
         final int width = lastColumn - firstColumn + 1;
         SimpleCellWalkContext ctx = new SimpleCellWalkContext();
-        Row currentRow = null;
-        Cell currentCell = null;
+        Row currentRow;
+        Cell currentCell;
 
         for (ctx.rowNumber = firstRow; ctx.rowNumber <= lastRow; ++ctx.rowNumber) {
             currentRow = sheet.getRow(ctx.rowNumber);
@@ -92,10 +94,9 @@ public class CellWalk {
                     continue;
                 }
 
-                long rowSize = ArithmeticUtils.mulAndCheck(
-                        (long)ArithmeticUtils.subAndCheck(ctx.rowNumber, firstRow), (long)width);
+                long rowSize = mulAndCheck(subAndCheck(ctx.rowNumber, firstRow), (long)width);
 
-                ctx.ordinalNumber = ArithmeticUtils.addAndCheck(rowSize, (ctx.colNumber - firstColumn + 1));
+                ctx.ordinalNumber = addAndCheck(rowSize, (ctx.colNumber - firstColumn + 1));
 
                 handler.onCell(currentCell, ctx);
             }
@@ -108,13 +109,11 @@ public class CellWalk {
 
     /**
      * Inner class to hold walk context.
-     *
-     * @author Roman Kashitsyn
      */
     private static class SimpleCellWalkContext implements CellWalkContext {
-        public long ordinalNumber;
-        public int rowNumber;
-        public int colNumber;
+        private long ordinalNumber;
+        private int rowNumber;
+        private int colNumber;
 
         @Override
         public long getOrdinalNumber() {
diff --git a/src/java/org/apache/poi/util/DrawingDump.java b/src/java/org/apache/poi/util/DrawingDump.java
index ef7b2d29ac..72d9580b65 100644
--- a/src/java/org/apache/poi/util/DrawingDump.java
+++ b/src/java/org/apache/poi/util/DrawingDump.java
@@ -15,7 +15,7 @@
    See the License for the specific language governing permissions and
    limitations under the License.
 ==================================================================== */
-        
+
 package org.apache.poi.util;
 
 import java.io.File;
@@ -37,23 +37,20 @@ public final class DrawingDump {
     }
 
     public static void main( String[] args ) throws IOException {
-        OutputStreamWriter osw = new OutputStreamWriter(System.out, Charset.defaultCharset());
-        PrintWriter pw = new PrintWriter(osw);
-        POIFSFileSystem fs = new POIFSFileSystem(new File(args[0]));
-        HSSFWorkbook wb = new HSSFWorkbook(fs);
-        try {
+        try (OutputStreamWriter osw = new OutputStreamWriter(System.out, Charset.defaultCharset());
+            PrintWriter pw = new PrintWriter(osw);
+            POIFSFileSystem fs = new POIFSFileSystem(new File(args[0]));
+            HSSFWorkbook wb = new HSSFWorkbook(fs)) {
+
             pw.println( "Drawing group:" );
             wb.dumpDrawingGroupRecords(true);
-    
+
             int i = 1;
             for (Sheet sheet : wb)
             {
                 pw.println( "Sheet " + i + "(" + sheet.getSheetName() + "):" );
                 ((HSSFSheet) sheet).dumpDrawingRecords(true, pw);
             }
-        } finally {
-            wb.close();
-            fs.close();
         }
     }
 }
diff --git a/src/java/org/apache/poi/util/IOUtils.java b/src/java/org/apache/poi/util/IOUtils.java
index 1a53cdd0b0..f1532b75e2 100644
--- a/src/java/org/apache/poi/util/IOUtils.java
+++ b/src/java/org/apache/poi/util/IOUtils.java
@@ -162,13 +162,13 @@ public final class IOUtils {
      * @return A byte array with the read bytes.
      * @throws IOException If reading data fails or EOF is encountered too early for the given length.
      */
-    public static byte[] toByteArray(InputStream stream, final long length, final int maxLength) throws IOException {
+    public static byte[] toByteArray(InputStream stream, final int length, final int maxLength) throws IOException {
         if (length < 0L || maxLength < 0L) {
             throw new RecordFormatException("Can't allocate an array of length < 0");
         }
-        if (length > (long)Integer.MAX_VALUE) {
-            throw new RecordFormatException("Can't allocate an array > "+Integer.MAX_VALUE);
-        }
+        // if (length > (long)Integer.MAX_VALUE) {
+        //     throw new RecordFormatException("Can't allocate an array > "+Integer.MAX_VALUE);
+        // }
         if ((length != Integer.MAX_VALUE) || (maxLength != Integer.MAX_VALUE)) {
             checkLength(length, maxLength);
         }