Use final.

Author: Gary Gregory

src/main/java/org/apache/commons/io/FileUtils.java

@@ -2132,7 +2132,7 @@ public static Collection<File> listFiles(
         try {
             final AccumulatorPathVisitor visitor = listAccumulate(directory, fileFilter, dirFilter);
             return visitor.getFileList().stream().map(Path::toFile).collect(Collectors.toList());
-        } catch (IOException e) {
+        } catch (final IOException e) {
             throw new IllegalArgumentException(e);
         }
     }
@@ -2180,7 +2180,7 @@ public static Collection<File> listFilesAndDirs(
             final List<Path> list = visitor.getFileList();
             list.addAll(visitor.getDirList());
             return list.stream().map(Path::toFile).collect(Collectors.toList());
-        } catch (IOException e) {
+        } catch (final IOException e) {
             throw new IllegalStateException(e);
         }
     }

src/main/java/org/apache/commons/io/file/PathUtils.java

@@ -293,7 +293,7 @@ public static PathCounters countDirectory(final Path directory) throws IOExcepti
      * @throws IOException if an I/O error occurs
      * @since 2.9.0
      */
-    public static Path createParentDirectories(final Path path, FileAttribute<?>... attrs) throws IOException {
+    public static Path createParentDirectories(final Path path, final FileAttribute<?>... attrs) throws IOException {
         final Path parent = path.getParent();
         if (parent == null) {
             return null;

src/main/java/org/apache/commons/io/filefilter/AndFileFilter.java

@@ -68,7 +68,7 @@ private AndFileFilter(final ArrayList<IOFileFilter> initialList) {
      * 
      * @param initialCapacity the initial capacity.
      */
-    private AndFileFilter(int initialCapacity) {
+    private AndFileFilter(final int initialCapacity) {
         this(new ArrayList<>(initialCapacity));
     }
 

src/main/java/org/apache/commons/io/filefilter/FalseFileFilter.java

@@ -100,13 +100,13 @@ public String toString() {
     }
 
     @Override
-    public IOFileFilter and(IOFileFilter fileFilter) {
+    public IOFileFilter and(final IOFileFilter fileFilter) {
         // FALSE AND expression <=> FALSE
         return INSTANCE;
     }
 
     @Override
-    public IOFileFilter or(IOFileFilter fileFilter) {
+    public IOFileFilter or(final IOFileFilter fileFilter) {
         // FALSE OR expression <=> expression
         return fileFilter;
     }

src/main/java/org/apache/commons/io/filefilter/PathVisitorFileFilter.java

@@ -71,7 +71,7 @@ public boolean accept(final File dir, final String name) {
     public FileVisitResult accept(final Path path, final BasicFileAttributes attributes) {
         try {
             return Files.isDirectory(path) ? pathVisitor.postVisitDirectory(path, null) : visitFile(path, attributes);
-        } catch (IOException e) {
+        } catch (final IOException e) {
             return handle(e);
         }
     }

src/main/java/org/apache/commons/io/input/BufferedFileChannelInputStream.java

@@ -154,7 +154,7 @@ private void clean(final DirectBuffer buffer) {
                   final Method cleanMethod = clsCleaner.getMethod("clean");
                   cleanMethod.invoke(cleaner);
               }
-            } catch (ReflectiveOperationException e) {
+            } catch (final ReflectiveOperationException e) {
                 throw new IllegalStateException(e);
             }
         } else {
@@ -165,7 +165,7 @@ private void clean(final DirectBuffer buffer) {
                 final Field unsafeField = clsUnsafe.getDeclaredField("theUnsafe");
                 unsafeField.setAccessible(true);
                 cleanerMethod.invoke(unsafeField.get(null), buffer);
-            } catch (ReflectiveOperationException e) {
+            } catch (final ReflectiveOperationException e) {
                 throw new IllegalStateException(e);
             }
         }

src/test/java/org/apache/commons/io/input/CharSequenceInputStreamTest.java

@@ -376,7 +376,7 @@ private void testAvailableRead(final String csName) throws Exception {
             int available = checkAvail(r, input.length());
             assertEquals(available - 1, r.skip(available - 1)); // skip all but one
             available = checkAvail(r, 1);
-            byte[] buff = new byte[available];
+            final byte[] buff = new byte[available];
             assertEquals(available, r.read(buff, 0, available));
         }
     }