Make private static classes final

Author: garydgregory

src/main/java/org/apache/commons/codec/digest/Blake3.java

@@ -365,7 +365,7 @@ private static int[] parentChainingValue(
      * Represents the state just prior to either producing an eight word chaining value or any number of output bytes
      * when the ROOT flag is set.
      */
-    private static class Output {
+    private static final class Output {
         private final int[] inputChainingValue;
         private final int[] blockWords;
         private final long counter;
@@ -405,7 +405,7 @@ private void rootOutputBytes(final byte[] out, int offset, int length) {
         }
     }
 
-    private static class ChunkState {
+    private static final class ChunkState {
         private int[] chainingValue;
         private final long chunkCounter;
         private final int flags;
@@ -458,7 +458,7 @@ private Output output() {
         }
     }
 
-    private static class EngineState {
+    private static final class EngineState {
         private final int[] key;
         private final int flags;
         // Space for 54 subtree chaining values: 2^54 * CHUNK_LEN = 2^64

src/test/java/org/apache/commons/codec/binary/BaseNCodecTest.java

@@ -379,7 +379,7 @@ public void testEnsureBufferSizeThrowsOnOverflow() {
      * Extend BaseNCodec without implementation (no operations = NoOp).
      * Used for testing the memory allocation in {@link BaseNCodec#ensureBufferSize(int, Context)}.
      */
-    private static class NoOpBaseNCodec extends BaseNCodec {
+    private static final class NoOpBaseNCodec extends BaseNCodec {
         NoOpBaseNCodec() {
             super(0, 0, 0, 0);
         }

src/test/java/org/apache/commons/codec/digest/PureJavaCrc32Test.java

@@ -362,7 +362,7 @@ public void run() {
       return new BenchResult(expected, sum/results.length);
     }
 
-    private static class BenchResult {
+    private static final class BenchResult {
       /** CRC value */
       final long value;
       /** Speed (MB per second) */