diff --git a/codec/src/main/java/io/netty/handler/codec/compression/Bzip2Decoder.java b/codec/src/main/java/io/netty/handler/codec/compression/Bzip2Decoder.java
index 98f470169b83..b66ff5956f3a 100644
--- a/codec/src/main/java/io/netty/handler/codec/compression/Bzip2Decoder.java
+++ b/codec/src/main/java/io/netty/handler/codec/compression/Bzip2Decoder.java
@@ -104,6 +104,7 @@ protected void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) t
 
                 streamCRC = 0;
                 currentState = State.INIT_BLOCK;
+                 // fall through
             case INIT_BLOCK:
                 if (!reader.hasReadableBytes(10)) {
                     return;
@@ -125,6 +126,7 @@ protected void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) t
                 }
                 blockCRC = reader.readInt();
                 currentState = State.INIT_BLOCK_PARAMS;
+                // fall through
             case INIT_BLOCK_PARAMS:
                 if (!reader.hasReadableBits(25)) {
                     return;
@@ -135,12 +137,14 @@ protected void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) t
                 blockDecompressor = new Bzip2BlockDecompressor(this.blockSize, blockCRC,
                                                                 blockRandomised, bwtStartPointer, reader);
                 currentState = State.RECEIVE_HUFFMAN_USED_MAP;
+                // fall through
             case RECEIVE_HUFFMAN_USED_MAP:
                 if (!reader.hasReadableBits(16)) {
                     return;
                 }
                 blockDecompressor.huffmanInUse16 = reader.readBits(16);
                 currentState = State.RECEIVE_HUFFMAN_USED_BITMAPS;
+                // fall through
             case RECEIVE_HUFFMAN_USED_BITMAPS:
                 Bzip2BlockDecompressor blockDecompressor = this.blockDecompressor;
                 final int inUse16 = blockDecompressor.huffmanInUse16;
@@ -175,6 +179,7 @@ protected void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) t
                 }
                 huffmanStageDecoder = new Bzip2HuffmanStageDecoder(reader, totalTables, alphaSize);
                 currentState = State.RECEIVE_SELECTORS_NUMBER;
+                // fall through
             case RECEIVE_SELECTORS_NUMBER:
                 if (!reader.hasReadableBits(15)) {
                     return;
@@ -186,6 +191,7 @@ protected void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) t
                 huffmanStageDecoder.selectors = new byte[totalSelectors];
 
                 currentState = State.RECEIVE_SELECTORS;
+                // fall through
             case RECEIVE_SELECTORS:
                 Bzip2HuffmanStageDecoder huffmanStageDecoder = this.huffmanStageDecoder;
                 byte[] selectors = huffmanStageDecoder.selectors;
@@ -209,6 +215,7 @@ protected void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) t
                 }
 
                 currentState = State.RECEIVE_HUFFMAN_LENGTH;
+                // fall through
             case RECEIVE_HUFFMAN_LENGTH:
                 huffmanStageDecoder = this.huffmanStageDecoder;
                 totalTables = huffmanStageDecoder.totalTables;
@@ -268,6 +275,7 @@ protected void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) t
                 // Finally create the Huffman tables
                 huffmanStageDecoder.createHuffmanDecodingTables();
                 currentState = State.DECODE_HUFFMAN_DATA;
+                // fall through
             case DECODE_HUFFMAN_DATA:
                 blockDecompressor = this.blockDecompressor;
                 final int oldReaderIndex = in.readerIndex();
diff --git a/codec/src/main/java/io/netty/handler/codec/compression/Bzip2Encoder.java b/codec/src/main/java/io/netty/handler/codec/compression/Bzip2Encoder.java
index a9dfe55c9ed5..1282ca295dfe 100644
--- a/codec/src/main/java/io/netty/handler/codec/compression/Bzip2Encoder.java
+++ b/codec/src/main/java/io/netty/handler/codec/compression/Bzip2Encoder.java
@@ -113,9 +113,11 @@ protected void encode(ChannelHandlerContext ctx, ByteBuf in, ByteBuf out) throws
                     out.writeMedium(MAGIC_NUMBER);
                     out.writeByte('0' + streamBlockSize / BASE_BLOCK_SIZE);
                     currentState = State.INIT_BLOCK;
+                    // fall through
                 case INIT_BLOCK:
                     blockCompressor = new Bzip2BlockCompressor(writer, streamBlockSize);
                     currentState = State.WRITE_DATA;
+                    // fall through
                 case WRITE_DATA:
                     if (!in.isReadable()) {
                         return;
@@ -132,6 +134,7 @@ protected void encode(ChannelHandlerContext ctx, ByteBuf in, ByteBuf out) throws
                         }
                     }
                     currentState = State.CLOSE_BLOCK;
+                    // fall through
                 case CLOSE_BLOCK:
                     closeBlock(out);
                     currentState = State.INIT_BLOCK;
diff --git a/codec/src/main/java/io/netty/handler/codec/compression/Bzip2HuffmanAllocator.java b/codec/src/main/java/io/netty/handler/codec/compression/Bzip2HuffmanAllocator.java
index 10f14b09d551..64a7915754c6 100644
--- a/codec/src/main/java/io/netty/handler/codec/compression/Bzip2HuffmanAllocator.java
+++ b/codec/src/main/java/io/netty/handler/codec/compression/Bzip2HuffmanAllocator.java
@@ -159,6 +159,7 @@ static void allocateHuffmanCodeLengths(final int[] array, final int maximumLengt
         switch (array.length) {
             case 2:
                 array[1] = 1;
+                // fall through
             case 1:
                 array[0] = 1;
                 return;
diff --git a/codec/src/main/java/io/netty/handler/codec/compression/FastLz.java b/codec/src/main/java/io/netty/handler/codec/compression/FastLz.java
index 9251deb581f9..d23e44cb39d2 100644
--- a/codec/src/main/java/io/netty/handler/codec/compression/FastLz.java
+++ b/codec/src/main/java/io/netty/handler/codec/compression/FastLz.java
@@ -90,6 +90,7 @@ static int calculateOutputBufferLength(int inputLength) {
      *
      * If the input is not compressible, the return value might be larger than length (input buffer size).
      */
+    @SuppressWarnings("IdentityBinaryExpression")
     static int compress(final byte[] input, final int inOffset, final int inLength,
                         final byte[] output, final int outOffset, final int proposedLevel) {
         final int level;
diff --git a/codec/src/main/java/io/netty/handler/codec/compression/FastLzFrameDecoder.java b/codec/src/main/java/io/netty/handler/codec/compression/FastLzFrameDecoder.java
index 341f72a18525..52ce381666f6 100644
--- a/codec/src/main/java/io/netty/handler/codec/compression/FastLzFrameDecoder.java
+++ b/codec/src/main/java/io/netty/handler/codec/compression/FastLzFrameDecoder.java
@@ -126,6 +126,7 @@ protected void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) t
                 hasChecksum = (options & 0x10) == BLOCK_WITH_CHECKSUM;
 
                 currentState = State.INIT_BLOCK_PARAMS;
+                // fall through
             case INIT_BLOCK_PARAMS:
                 if (in.readableBytes() < 2 + (isCompressed ? 2 : 0) + (hasChecksum ? 4 : 0)) {
                     break;
@@ -135,6 +136,7 @@ protected void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) t
                 originalLength = isCompressed ? in.readUnsignedShort() : chunkLength;
 
                 currentState = State.DECOMPRESS_DATA;
+                // fall through
             case DECOMPRESS_DATA:
                 final int chunkLength = this.chunkLength;
                 if (in.readableBytes() < chunkLength) {
diff --git a/codec/src/main/java/io/netty/handler/codec/compression/JdkZlibDecoder.java b/codec/src/main/java/io/netty/handler/codec/compression/JdkZlibDecoder.java
index d9b4b914f19e..865c0546eb88 100644
--- a/codec/src/main/java/io/netty/handler/codec/compression/JdkZlibDecoder.java
+++ b/codec/src/main/java/io/netty/handler/codec/compression/JdkZlibDecoder.java
@@ -269,6 +269,7 @@ private boolean readGZIPHeader(ByteBuf in) {
                 crc.update(in.readUnsignedByte()); // operating system
 
                 gzipState = GzipState.FLG_READ;
+                // fall through
             case FLG_READ:
                 if ((flags & FEXTRA) != 0) {
                     if (in.readableBytes() < 2) {
@@ -282,6 +283,7 @@ private boolean readGZIPHeader(ByteBuf in) {
                     xlen |= xlen1 << 8 | xlen2;
                 }
                 gzipState = GzipState.XLEN_READ;
+                // fall through
             case XLEN_READ:
                 if (xlen != -1) {
                     if (in.readableBytes() < xlen) {
@@ -291,6 +293,7 @@ private boolean readGZIPHeader(ByteBuf in) {
                     in.skipBytes(xlen);
                 }
                 gzipState = GzipState.SKIP_FNAME;
+                // fall through
             case SKIP_FNAME:
                 if ((flags & FNAME) != 0) {
                     if (!in.isReadable()) {
@@ -305,6 +308,7 @@ private boolean readGZIPHeader(ByteBuf in) {
                     } while (in.isReadable());
                 }
                 gzipState = GzipState.SKIP_COMMENT;
+                // fall through
             case SKIP_COMMENT:
                 if ((flags & FCOMMENT) != 0) {
                     if (!in.isReadable()) {
@@ -319,6 +323,7 @@ private boolean readGZIPHeader(ByteBuf in) {
                     } while (in.isReadable());
                 }
                 gzipState = GzipState.PROCESS_FHCRC;
+                // fall through
             case PROCESS_FHCRC:
                 if ((flags & FHCRC) != 0) {
                     if (in.readableBytes() < 4) {
@@ -328,6 +333,7 @@ private boolean readGZIPHeader(ByteBuf in) {
                 }
                 crc.reset();
                 gzipState = GzipState.HEADER_END;
+                // fall through
             case HEADER_END:
                 return true;
             default:
diff --git a/codec/src/main/java/io/netty/handler/codec/compression/JdkZlibEncoder.java b/codec/src/main/java/io/netty/handler/codec/compression/JdkZlibEncoder.java
index 49be347890c3..f039fa66e849 100644
--- a/codec/src/main/java/io/netty/handler/codec/compression/JdkZlibEncoder.java
+++ b/codec/src/main/java/io/netty/handler/codec/compression/JdkZlibEncoder.java
@@ -242,6 +242,8 @@ protected final ByteBuf allocateBuffer(ChannelHandlerContext ctx, ByteBuf msg,
                 case ZLIB:
                     sizeEstimate += 2; // first two magic bytes
                     break;
+                default:
+                    // no op
             }
         }
         return ctx.alloc().heapBuffer(sizeEstimate);
diff --git a/codec/src/main/java/io/netty/handler/codec/compression/Lz4FrameDecoder.java b/codec/src/main/java/io/netty/handler/codec/compression/Lz4FrameDecoder.java
index 1dbe3f8c6e81..addf105df888 100644
--- a/codec/src/main/java/io/netty/handler/codec/compression/Lz4FrameDecoder.java
+++ b/codec/src/main/java/io/netty/handler/codec/compression/Lz4FrameDecoder.java
@@ -202,6 +202,7 @@ protected void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) t
                 this.currentChecksum = currentChecksum;
 
                 currentState = State.DECOMPRESS_DATA;
+                // fall through
             case DECOMPRESS_DATA:
                 blockType = this.blockType;
                 compressedLength = this.compressedLength;
diff --git a/codec/src/main/java/io/netty/handler/codec/compression/LzfDecoder.java b/codec/src/main/java/io/netty/handler/codec/compression/LzfDecoder.java
index 2aef048030c2..61a5f0edbb01 100644
--- a/codec/src/main/java/io/netty/handler/codec/compression/LzfDecoder.java
+++ b/codec/src/main/java/io/netty/handler/codec/compression/LzfDecoder.java
@@ -140,6 +140,7 @@ protected void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) t
                 if (type != BLOCK_TYPE_COMPRESSED) {
                     break;
                 }
+                // fall through
             case INIT_ORIGINAL_LENGTH:
                 if (in.readableBytes() < 2) {
                     break;
@@ -147,6 +148,7 @@ protected void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) t
                 originalLength = in.readUnsignedShort();
 
                 currentState = State.DECOMPRESS_DATA;
+                // fall through
             case DECOMPRESS_DATA:
                 final int chunkLength = this.chunkLength;
                 if (in.readableBytes() < chunkLength) {
diff --git a/codec/src/main/java/io/netty/handler/codec/compression/Snappy.java b/codec/src/main/java/io/netty/handler/codec/compression/Snappy.java
index 3173557e328c..1c72021e033a 100644
--- a/codec/src/main/java/io/netty/handler/codec/compression/Snappy.java
+++ b/codec/src/main/java/io/netty/handler/codec/compression/Snappy.java
@@ -272,6 +272,7 @@ public void decode(ByteBuf in, ByteBuf out) {
             switch (state) {
             case READY:
                 state = State.READING_PREAMBLE;
+                // fall through
             case READING_PREAMBLE:
                 int uncompressedLength = readPreamble(in);
                 if (uncompressedLength == PREAMBLE_NOT_FULL) {
@@ -285,6 +286,7 @@ public void decode(ByteBuf in, ByteBuf out) {
                 }
                 out.ensureWritable(uncompressedLength);
                 state = State.READING_TAG;
+                // fall through
             case READING_TAG:
                 if (!in.isReadable()) {
                     return;
diff --git a/common/src/main/java/io/netty/util/internal/StringUtil.java b/common/src/main/java/io/netty/util/internal/StringUtil.java
index 14fe2c1d22ac..8841001789a7 100644
--- a/common/src/main/java/io/netty/util/internal/StringUtil.java
+++ b/common/src/main/java/io/netty/util/internal/StringUtil.java
@@ -490,6 +490,7 @@ public static List<CharSequence> unescapeCsvFields(CharSequence value) {
                             break;
                         }
                         // double-quote appears without being enclosed with double-quotes
+                        // fall through
                     case LINE_FEED:
                         // fall through
                     case CARRIAGE_RETURN:
diff --git a/transport/src/main/java/io/netty/channel/nio/NioEventLoop.java b/transport/src/main/java/io/netty/channel/nio/NioEventLoop.java
index 331182e0e777..3da502ab9ef0 100644
--- a/transport/src/main/java/io/netty/channel/nio/NioEventLoop.java
+++ b/transport/src/main/java/io/netty/channel/nio/NioEventLoop.java
@@ -439,8 +439,8 @@ protected void run() {
                         if (wakenUp.get()) {
                             selector.wakeup();
                         }
+                        // fall through
                     default:
-                        // fallthrough
                 }
 
                 cancelledKeys = 0;