Reduce exception instantiation overhead in SslHandler / Reduce unnecessary empty array creation

- Added EmptyArrays as an internal utility class

buffer/src/main/java/io/netty/buffer/DefaultCompositeByteBuf.java

@@ -16,6 +16,7 @@
 package io.netty.buffer;
 
 import io.netty.util.ResourceLeak;
+import io.netty.util.internal.EmptyArrays;
 import io.netty.util.internal.PlatformDependent;
 
 import java.io.IOException;
@@ -42,8 +43,6 @@ import java.util.Queue;
  */
 public class DefaultCompositeByteBuf extends AbstractReferenceCountedByteBuf implements CompositeByteBuf {
 
-    private static final ByteBuffer[] EMPTY_NIOBUFFERS = new ByteBuffer[0];
-
     private final ResourceLeak leak;
     private final ByteBufAllocator alloc;
     private final boolean direct;
@@ -1049,7 +1048,7 @@ public class DefaultCompositeByteBuf extends AbstractReferenceCountedByteBuf imp
     public ByteBuffer[] nioBuffers(int index, int length) {
         checkIndex(index, length);
         if (length == 0) {
-            return EMPTY_NIOBUFFERS;
+            return EmptyArrays.EMPTY_BYTE_BUFFERS;
         }
 
         List<ByteBuffer> buffers = new ArrayList<ByteBuffer>(components.size());

buffer/src/main/java/io/netty/buffer/EmptyByteBuf.java

@@ -16,6 +16,7 @@
 
 package io.netty.buffer;
 
+import io.netty.util.internal.EmptyArrays;
 import io.netty.util.internal.PlatformDependent;
 
 import java.io.InputStream;
@@ -32,7 +33,6 @@ import java.nio.charset.Charset;
  */
 public final class EmptyByteBuf implements ByteBuf {
 
-    private static final byte[] EMPTY_ARRAY = new byte[0];
     private static final ByteBuffer EMPTY_BYTE_BUFFER = ByteBuffer.allocateDirect(0);
     private static final long EMPTY_BYTE_BUFFER_ADDRESS;
 
@@ -767,7 +767,7 @@ public final class EmptyByteBuf implements ByteBuf {
 
     @Override
     public byte[] array() {
-        return EMPTY_ARRAY;
+        return EmptyArrays.EMPTY_BYTES;
     }
 
     @Override

buffer/src/test/java/io/netty/buffer/AbstractByteBufTest.java

@@ -32,6 +32,7 @@ import java.util.Random;
 import java.util.Set;
 
 import static io.netty.buffer.Unpooled.*;
+import static io.netty.util.internal.EmptyArrays.*;
 import static org.hamcrest.CoreMatchers.*;
 import static org.junit.Assert.*;
 
@@ -42,7 +43,6 @@ public abstract class AbstractByteBufTest {
 
     private static final int CAPACITY = 4096; // Must be even
     private static final int BLOCK_SIZE = 128;
-    private static final byte[] EMPTY_ARRAY = new byte[0];
 
     private static final Queue<ByteBuf> freeLaterQueue = new ArrayDeque<ByteBuf>();
 
@@ -235,12 +235,12 @@ public abstract class AbstractByteBufTest {
 
     @Test(expected = IndexOutOfBoundsException.class)
     public void getByteArrayBoundaryCheck1() {
-        buffer.getBytes(-1, EMPTY_ARRAY);
+        buffer.getBytes(-1, EMPTY_BYTES);
     }
 
     @Test(expected = IndexOutOfBoundsException.class)
     public void getByteArrayBoundaryCheck2() {
-        buffer.getBytes(-1, EMPTY_ARRAY, 0, 0);
+        buffer.getBytes(-1, EMPTY_BYTES, 0, 0);
     }
 
     @Test

buffer/src/test/java/io/netty/buffer/AbstractCompositeByteBufTest.java

@@ -24,13 +24,13 @@ import java.util.Collections;
 import java.util.List;
 
 import static io.netty.buffer.Unpooled.*;
+import static io.netty.util.internal.EmptyArrays.*;
 import static org.hamcrest.CoreMatchers.*;
 import static org.junit.Assert.*;
 
 /**
  * An abstract test class for composite channel buffers
  */
-@SuppressWarnings("ZeroLengthArrayAllocation")
 public abstract class AbstractCompositeByteBufTest extends AbstractByteBufTest {
 
     private final ByteOrder order;
@@ -418,7 +418,7 @@ public abstract class AbstractCompositeByteBufTest extends AbstractByteBufTest {
     public void testEmptyBuffer() {
         ByteBuf b = freeLater(wrappedBuffer(new byte[]{1, 2}, new byte[]{3, 4}));
         b.readBytes(new byte[4]);
-        b.readBytes(new byte[0]);
+        b.readBytes(EMPTY_BYTES);
     }
 
     // Test for https://github.com/netty/netty/issues/1060

buffer/src/test/java/io/netty/buffer/ByteBufStreamTest.java

@@ -20,12 +20,12 @@ import org.junit.Test;
 import java.io.EOFException;
 import java.nio.charset.Charset;
 
+import static io.netty.util.internal.EmptyArrays.*;
 import static org.junit.Assert.*;
 
 /**
  * Tests channel buffer streams
  */
-@SuppressWarnings("ZeroLengthArrayAllocation")
 public class ByteBufStreamTest {
 
     @Test
@@ -56,7 +56,7 @@ public class ByteBufStreamTest {
         out.writeShort(49152);
         out.writeUTF("Hello, World!");
         out.writeBytes("The first line\r\r\n");
-        out.write(new byte[0]);
+        out.write(EMPTY_BYTES);
         out.write(new byte[] { 1, 2, 3, 4 });
         out.write(new byte[] { 1, 3, 3, 4 }, 0, 0);
         out.close();

buffer/src/test/java/io/netty/buffer/UnpooledTest.java

@@ -31,14 +31,17 @@ import java.util.Map.Entry;
 import java.util.Queue;
 
 import static io.netty.buffer.Unpooled.*;
+import static io.netty.util.internal.EmptyArrays.*;
 import static org.junit.Assert.*;
 
 /**
  * Tests channel buffers
  */
-@SuppressWarnings("ZeroLengthArrayAllocation")
 public class UnpooledTest {
 
+    private static final ByteBuf[] EMPTY_BYTE_BUFS = new ByteBuf[0];
+    private static final byte[][] EMPTY_BYTES_2D = new byte[0][];
+
     private static final Queue<ByteBuf> freeLaterQueue = new ArrayDeque<ByteBuf>();
 
     protected ByteBuf freeLater(ByteBuf buf) {
@@ -82,7 +85,7 @@ public class UnpooledTest {
     @Test
     public void testHashCode() {
         Map<byte[], Integer> map = new LinkedHashMap<byte[], Integer>();
-        map.put(new byte[0], 1);
+        map.put(EMPTY_BYTES, 1);
         map.put(new byte[] { 1 }, 32);
         map.put(new byte[] { 2 }, 33);
         map.put(new byte[] { 0, 1 }, 962);
@@ -183,31 +186,31 @@ public class UnpooledTest {
 
     @Test
     public void shouldReturnEmptyBufferWhenLengthIsZero() {
-        assertSame(EMPTY_BUFFER, wrappedBuffer(new byte[0]));
+        assertSame(EMPTY_BUFFER, wrappedBuffer(EMPTY_BYTES));
         assertSame(EMPTY_BUFFER, wrappedBuffer(new byte[8], 0, 0));
         assertSame(EMPTY_BUFFER, wrappedBuffer(new byte[8], 8, 0));
         assertSame(EMPTY_BUFFER, wrappedBuffer(ByteBuffer.allocateDirect(0)));
         assertSame(EMPTY_BUFFER, wrappedBuffer(EMPTY_BUFFER));
-        assertSame(EMPTY_BUFFER, wrappedBuffer(new byte[0][]));
+        assertSame(EMPTY_BUFFER, wrappedBuffer(EMPTY_BYTES_2D));
-        assertSame(EMPTY_BUFFER, wrappedBuffer(new byte[][] { new byte[0] }));
+        assertSame(EMPTY_BUFFER, wrappedBuffer(new byte[][] { EMPTY_BYTES }));
-        assertSame(EMPTY_BUFFER, wrappedBuffer(new ByteBuffer[0]));
+        assertSame(EMPTY_BUFFER, wrappedBuffer(EMPTY_BYTE_BUFFERS));
         assertSame(EMPTY_BUFFER, wrappedBuffer(new ByteBuffer[] { ByteBuffer.allocate(0) }));
         assertSame(EMPTY_BUFFER, wrappedBuffer(ByteBuffer.allocate(0), ByteBuffer.allocate(0)));
-        assertSame(EMPTY_BUFFER, wrappedBuffer(new ByteBuf[0]));
+        assertSame(EMPTY_BUFFER, wrappedBuffer(EMPTY_BYTE_BUFS));
         assertSame(EMPTY_BUFFER, wrappedBuffer(new ByteBuf[] { buffer(0) }));
         assertSame(EMPTY_BUFFER, wrappedBuffer(buffer(0), buffer(0)));
 
-        assertSame(EMPTY_BUFFER, copiedBuffer(new byte[0]));
+        assertSame(EMPTY_BUFFER, copiedBuffer(EMPTY_BYTES));
         assertSame(EMPTY_BUFFER, copiedBuffer(new byte[8], 0, 0));
         assertSame(EMPTY_BUFFER, copiedBuffer(new byte[8], 8, 0));
         assertSame(EMPTY_BUFFER, copiedBuffer(ByteBuffer.allocateDirect(0)));
         assertSame(EMPTY_BUFFER, copiedBuffer(EMPTY_BUFFER));
-        assertSame(EMPTY_BUFFER, copiedBuffer(new byte[0][]));
+        assertSame(EMPTY_BUFFER, copiedBuffer(EMPTY_BYTES_2D));
-        assertSame(EMPTY_BUFFER, copiedBuffer(new byte[][] { new byte[0] }));
+        assertSame(EMPTY_BUFFER, copiedBuffer(new byte[][] { EMPTY_BYTES }));
-        assertSame(EMPTY_BUFFER, copiedBuffer(new ByteBuffer[0]));
+        assertSame(EMPTY_BUFFER, copiedBuffer(EMPTY_BYTE_BUFFERS));
         assertSame(EMPTY_BUFFER, copiedBuffer(new ByteBuffer[] { ByteBuffer.allocate(0) }));
         assertSame(EMPTY_BUFFER, copiedBuffer(ByteBuffer.allocate(0), ByteBuffer.allocate(0)));
-        assertSame(EMPTY_BUFFER, copiedBuffer(new ByteBuf[0]));
+        assertSame(EMPTY_BUFFER, copiedBuffer(EMPTY_BYTE_BUFS));
         assertSame(EMPTY_BUFFER, copiedBuffer(new ByteBuf[] { buffer(0) }));
         assertSame(EMPTY_BUFFER, copiedBuffer(buffer(0), buffer(0)));
     }
@@ -370,7 +373,7 @@ public class UnpooledTest {
         }
 
         try {
-            buf.setBytes(0, new byte[0], 0, 0);
+            buf.setBytes(0, EMPTY_BYTES, 0, 0);
             fail();
         } catch (UnsupportedOperationException e) {
             // Expected
@@ -443,7 +446,7 @@ public class UnpooledTest {
         assertFalse(buffer.isReadable());
 
         assertEquals(0, Unpooled.copyInt(null).capacity());
-        assertEquals(0, Unpooled.copyInt(new int[0]).capacity());
+        assertEquals(0, Unpooled.copyInt(EMPTY_INTS).capacity());
     }
 
     @Test
@@ -463,7 +466,7 @@ public class UnpooledTest {
         assertFalse(buffer.isReadable());
 
         assertEquals(0, Unpooled.copyShort((short[]) null).capacity());
-        assertEquals(0, Unpooled.copyShort(new short[0]).capacity());
+        assertEquals(0, Unpooled.copyShort(EMPTY_SHORTS).capacity());
     }
 
     @Test
@@ -475,7 +478,7 @@ public class UnpooledTest {
         assertFalse(buffer.isReadable());
 
         assertEquals(0, Unpooled.copyShort((int[]) null).capacity());
-        assertEquals(0, Unpooled.copyShort(new int[0]).capacity());
+        assertEquals(0, Unpooled.copyShort(EMPTY_INTS).capacity());
     }
 
     @Test
@@ -495,7 +498,7 @@ public class UnpooledTest {
         assertFalse(buffer.isReadable());
 
         assertEquals(0, Unpooled.copyMedium(null).capacity());
-        assertEquals(0, Unpooled.copyMedium(new int[0]).capacity());
+        assertEquals(0, Unpooled.copyMedium(EMPTY_INTS).capacity());
     }
 
     @Test
@@ -515,7 +518,7 @@ public class UnpooledTest {
         assertFalse(buffer.isReadable());
 
         assertEquals(0, Unpooled.copyLong(null).capacity());
-        assertEquals(0, Unpooled.copyLong(new long[0]).capacity());
+        assertEquals(0, Unpooled.copyLong(EMPTY_LONGS).capacity());
     }
 
     @Test
@@ -535,7 +538,7 @@ public class UnpooledTest {
         assertFalse(buffer.isReadable());
 
         assertEquals(0, Unpooled.copyFloat(null).capacity());
-        assertEquals(0, Unpooled.copyFloat(new float[0]).capacity());
+        assertEquals(0, Unpooled.copyFloat(EMPTY_FLOATS).capacity());
     }
 
     @Test
@@ -555,7 +558,7 @@ public class UnpooledTest {
         assertFalse(buffer.isReadable());
 
         assertEquals(0, Unpooled.copyDouble(null).capacity());
-        assertEquals(0, Unpooled.copyDouble(new double[0]).capacity());
+        assertEquals(0, Unpooled.copyDouble(EMPTY_DOUBLES).capacity());
     }
 
     @Test
@@ -567,7 +570,7 @@ public class UnpooledTest {
         assertFalse(buffer.isReadable());
 
         assertEquals(0, Unpooled.copyBoolean(null).capacity());
-        assertEquals(0, Unpooled.copyBoolean(new boolean[0]).capacity());
+        assertEquals(0, Unpooled.copyBoolean(EMPTY_BOOLEANS).capacity());
     }
 
     @Test

codec-http/src/main/java/io/netty/handler/codec/http/multipart/AbstractDiskHttpData.java

@@ -17,6 +17,7 @@ package io.netty.handler.codec.http.multipart;
 
 import io.netty.buffer.ByteBuf;
 import io.netty.handler.codec.http.HttpConstants;
+import io.netty.util.internal.EmptyArrays;
 
 import java.io.File;
 import java.io.FileInputStream;
@@ -222,7 +223,7 @@ public abstract class AbstractDiskHttpData extends AbstractHttpData {
     @Override
     public byte[] get() throws IOException {
         if (file == null) {
-            return new byte[0];
+            return EmptyArrays.EMPTY_BYTES;
         }
         return readFrom(file);
     }

codec-http/src/main/java/io/netty/handler/codec/http/websocketx/CloseWebSocketFrame.java

@@ -18,14 +18,13 @@ package io.netty.handler.codec.http.websocketx;
 import io.netty.buffer.ByteBuf;
 import io.netty.buffer.Unpooled;
 import io.netty.util.CharsetUtil;
+import io.netty.util.internal.EmptyArrays;
 
 /**
  * Web Socket Frame for closing the connection
  */
 public class CloseWebSocketFrame extends WebSocketFrame {
 
-    private static final byte[] EMTPY_REASON = new byte[0];
-
     /**
      * Creates a new empty close frame.
      */
@@ -76,7 +75,7 @@ public class CloseWebSocketFrame extends WebSocketFrame {
     }
 
     private static ByteBuf newBinaryData(int statusCode, String reasonText) {
-        byte[] reasonBytes = EMTPY_REASON;
+        byte[] reasonBytes = EmptyArrays.EMPTY_BYTES;
         if (reasonText != null) {
             reasonBytes = reasonText.getBytes(CharsetUtil.UTF_8);
         }

codec-http/src/main/java/io/netty/handler/codec/http/websocketx/WebSocketServerHandshaker.java

@@ -30,6 +30,7 @@ import io.netty.handler.codec.http.HttpObjectAggregator;
 import io.netty.handler.codec.http.HttpRequestDecoder;
 import io.netty.handler.codec.http.HttpResponseEncoder;
 import io.netty.handler.codec.http.HttpServerCodec;
+import io.netty.util.internal.EmptyArrays;
 import io.netty.util.internal.StringUtil;
 import io.netty.util.internal.logging.InternalLogger;
 import io.netty.util.internal.logging.InternalLoggerFactory;
@@ -44,8 +45,6 @@ import java.util.Set;
 public abstract class WebSocketServerHandshaker {
     protected static final InternalLogger logger = InternalLoggerFactory.getInstance(WebSocketServerHandshaker.class);
 
-    private static final String[] EMPTY_ARRAY = new String[0];
-
     private final String uri;
 
     private final String[] subprotocols;
@@ -81,7 +80,7 @@ public abstract class WebSocketServerHandshaker {
             }
             this.subprotocols = subprotocolArray;
         } else {
-            this.subprotocols = EMPTY_ARRAY;
+            this.subprotocols = EmptyArrays.EMPTY_STRINGS;
         }
         this.maxFramePayloadLength = maxFramePayloadLength;
     }

codec-http/src/main/java/io/netty/handler/codec/spdy/SpdySessionHandler.java

@@ -24,6 +24,7 @@ import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.ChannelInboundMessageHandler;
 import io.netty.channel.ChannelOutboundMessageHandler;
 import io.netty.channel.ChannelPromise;
+import io.netty.util.internal.EmptyArrays;
 
 import java.util.concurrent.atomic.AtomicInteger;
 
@@ -38,10 +39,8 @@ public class SpdySessionHandler
     private static final SpdyProtocolException STREAM_CLOSED = new SpdyProtocolException("Stream closed");
 
     static {
-        @SuppressWarnings("ZeroLengthArrayAllocation")
+        PROTOCOL_EXCEPTION.setStackTrace(EmptyArrays.EMPTY_STACK_TRACE);
-        StackTraceElement[] emptyTrace = new StackTraceElement[0];
+        STREAM_CLOSED.setStackTrace(EmptyArrays.EMPTY_STACK_TRACE);
-        PROTOCOL_EXCEPTION.setStackTrace(emptyTrace);
-        STREAM_CLOSED.setStackTrace(emptyTrace);
     }
 
     private final SpdySession spdySession = new SpdySession();

codec/src/main/java/io/netty/handler/codec/compression/JZlibEncoder.java

@@ -23,6 +23,7 @@ import io.netty.channel.ChannelFuture;
 import io.netty.channel.ChannelFutureListener;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.ChannelPromise;
+import io.netty.util.internal.EmptyArrays;
 
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicBoolean;
@@ -33,8 +34,6 @@ import java.util.concurrent.atomic.AtomicBoolean;
  */
 public class JZlibEncoder extends ZlibEncoder {
 
-    private static final byte[] EMPTY_ARRAY = new byte[0];
-
     private final Deflater z = new Deflater();
     private final AtomicBoolean finished = new AtomicBoolean();
     private volatile ChannelHandlerContext ctx;
@@ -367,7 +366,7 @@ public class JZlibEncoder extends ZlibEncoder {
         synchronized (z) {
             try {
                 // Configure input.
-                z.next_in = EMPTY_ARRAY;
+                z.next_in = EmptyArrays.EMPTY_BYTES;
                 z.next_in_index = 0;
                 z.avail_in = 0;
 

codec/src/test/java/io/netty/handler/codec/bytes/ByteArrayDecoderTest.java

@@ -16,6 +16,7 @@
 package io.netty.handler.codec.bytes;
 
 import io.netty.channel.embedded.EmbeddedMessageChannel;
+import io.netty.util.internal.EmptyArrays;
 import org.junit.Before;
 import org.junit.Test;
 
@@ -48,7 +49,7 @@ public class ByteArrayDecoderTest {
     @Test
     public void testDecodeEmpty() {
         ch.writeInbound(EMPTY_BUFFER);
-        assertThat((byte[]) ch.readInbound(), is(new byte[0]));
+        assertThat((byte[]) ch.readInbound(), is(EmptyArrays.EMPTY_BYTES));
     }
 
     @Test

codec/src/test/java/io/netty/handler/codec/bytes/ByteArrayEncoderTest.java

@@ -17,6 +17,7 @@ package io.netty.handler.codec.bytes;
 
 import io.netty.buffer.ByteBuf;
 import io.netty.channel.embedded.EmbeddedMessageChannel;
+import io.netty.util.internal.EmptyArrays;
 import org.junit.Before;
 import org.junit.Test;
 
@@ -47,8 +48,7 @@ public class ByteArrayEncoderTest {
 
     @Test
     public void testEncodeEmpty() {
-        byte[] b = new byte[0];
+        ch.writeOutbound(EmptyArrays.EMPTY_BYTES);
-        ch.writeOutbound(b);
         assertThat(ch.readOutbound(), nullValue());
     }
 

common/src/main/java/io/netty/util/internal/EmptyArrays.java

@@ -0,0 +1,36 @@
+/*
+ * Copyright 2013 The Netty Project
+ *
+ * The Netty Project licenses this file to you under the Apache License,
+ * version 2.0 (the "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at:
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
+
+package io.netty.util.internal;
+
+import java.nio.ByteBuffer;
+
+public final class EmptyArrays {
+
+    public static final byte[] EMPTY_BYTES = new byte[0];
+    public static final boolean[] EMPTY_BOOLEANS = new boolean[0];
+    public static final double[] EMPTY_DOUBLES = new double[0];
+    public static final float[] EMPTY_FLOATS = new float[0];
+    public static final int[] EMPTY_INTS = new int[0];
+    public static final short[] EMPTY_SHORTS = new short[0];
+    public static final long[] EMPTY_LONGS = new long[0];
+    public static final Object[] EMPTY_OBJECTS = new Object[0];
+    public static final String[] EMPTY_STRINGS = new String[0];
+    public static final StackTraceElement[] EMPTY_STACK_TRACE = new StackTraceElement[0];
+    public static final ByteBuffer[] EMPTY_BYTE_BUFFERS = new ByteBuffer[0];
+
+    private EmptyArrays() { }
+}

handler/src/main/java/io/netty/handler/ssl/SslHandler.java

@@ -35,6 +35,7 @@ import io.netty.util.concurrent.EventExecutor;
 import io.netty.util.concurrent.Future;
 import io.netty.util.concurrent.GenericFutureListener;
 import io.netty.util.concurrent.ImmediateExecutor;
+import io.netty.util.internal.EmptyArrays;
 import io.netty.util.internal.PlatformDependent;
 import io.netty.util.internal.logging.InternalLogger;
 import io.netty.util.internal.logging.InternalLoggerFactory;
@@ -163,6 +164,16 @@ public class SslHandler
             "^.*(?:connection.*reset|connection.*closed|broken.*pipe).*$",
             Pattern.CASE_INSENSITIVE);
 
+    private static final SSLException SSLENGINE_CLOSED = new SSLException("SSLEngine closed already");
+    private static final SSLException HANDSHAKE_TIMED_OUT = new SSLException("handshake timed out");
+    private static final ClosedChannelException CHANNEL_CLOSED = new ClosedChannelException();
+
+    static {
+        SSLENGINE_CLOSED.setStackTrace(EmptyArrays.EMPTY_STACK_TRACE);
+        HANDSHAKE_TIMED_OUT.setStackTrace(EmptyArrays.EMPTY_STACK_TRACE);
+        CHANNEL_CLOSED.setStackTrace(EmptyArrays.EMPTY_STACK_TRACE);
+    }
+
     private volatile ChannelHandlerContext ctx;
     private final SSLEngine engine;
     private final Executor delegatedTaskExecutor;
@@ -479,10 +490,9 @@ public class SslHandler
                     // Any further write attempts should be denied.
                     if (in.isReadable()) {
                         in.clear();
-                        SSLException e = new SSLException("SSLEngine already closed");
+                        promise.setFailure(SSLENGINE_CLOSED);
-                        promise.setFailure(e);
+                        ctx.fireExceptionCaught(SSLENGINE_CLOSED);
-                        ctx.fireExceptionCaught(e);
+                        flush0(ctx, bytesConsumed, SSLENGINE_CLOSED);
-                        flush0(ctx, bytesConsumed, e);
                         bytesConsumed = 0;
                     }
                     break;
@@ -597,9 +607,9 @@ public class SslHandler
 
     @Override
     public void channelInactive(ChannelHandlerContext ctx) throws Exception {
-        // Make sure the handshake future is notified when a connection has
+        // Make sure to release SSLEngine,
-        // been closed during handshake.
+        // and notify the handshake future if the connection has been closed during handshake.
-        setHandshakeFailure(new ClosedChannelException());
+        setHandshakeFailure(CHANNEL_CLOSED);
 
         try {
             inboundBufferUpdated(ctx);
@@ -983,9 +993,8 @@ public class SslHandler
                         return;
                     }
 
-                    SSLException e = new SSLException("handshake timed out");
+                    if (handshakePromise.tryFailure(HANDSHAKE_TIMED_OUT)) {
-                    if (handshakePromise.tryFailure(e)) {
+                        ctx.fireExceptionCaught(HANDSHAKE_TIMED_OUT);
-                        ctx.fireExceptionCaught(e);
                         ctx.close();
                     }
                 }

transport/src/main/java/io/netty/channel/ThreadPerChannelEventLoopGroup.java

@@ -18,6 +18,7 @@ package io.netty.channel;
 
 import io.netty.util.concurrent.AbstractEventExecutorGroup;
 import io.netty.util.concurrent.EventExecutor;
+import io.netty.util.internal.EmptyArrays;
 import io.netty.util.internal.PlatformDependent;
 import io.netty.util.internal.ReadOnlyIterator;
 
@@ -35,9 +36,6 @@ import java.util.concurrent.TimeUnit;
  */
 public class ThreadPerChannelEventLoopGroup extends AbstractEventExecutorGroup implements EventLoopGroup {
 
-    private static final Object[] NO_ARGS = new Object[0];
-    private static final StackTraceElement[] STACK_ELEMENTS = new StackTraceElement[0];
-
     private final Object[] childArgs;
     private final int maxChannels;
     final ThreadFactory threadFactory;
@@ -88,7 +86,7 @@ public class ThreadPerChannelEventLoopGroup extends AbstractEventExecutorGroup i
         }
 
         if (args == null) {
-            childArgs = NO_ARGS;
+            childArgs = EmptyArrays.EMPTY_OBJECTS;
         } else {
             childArgs = args.clone();
         }
@@ -97,7 +95,7 @@ public class ThreadPerChannelEventLoopGroup extends AbstractEventExecutorGroup i
         this.threadFactory = threadFactory;
 
         tooManyChannels = new ChannelException("too many channels (max: " + maxChannels + ')');
-        tooManyChannels.setStackTrace(STACK_ELEMENTS);
+        tooManyChannels.setStackTrace(EmptyArrays.EMPTY_STACK_TRACE);
     }
 
     /**

transport/src/main/java/io/netty/channel/socket/oio/OioDatagramChannel.java

@@ -27,6 +27,7 @@ import io.netty.channel.socket.DatagramChannel;
 import io.netty.channel.socket.DatagramChannelConfig;
 import io.netty.channel.socket.DatagramPacket;
 import io.netty.channel.socket.DefaultDatagramChannelConfig;
+import io.netty.util.internal.EmptyArrays;
 import io.netty.util.internal.PlatformDependent;
 import io.netty.util.internal.logging.InternalLogger;
 import io.netty.util.internal.logging.InternalLoggerFactory;
@@ -52,11 +53,9 @@ public class OioDatagramChannel extends AbstractOioMessageChannel
 
     private static final ChannelMetadata METADATA = new ChannelMetadata(BufType.MESSAGE, true);
 
-    private static final byte[] EMPTY_DATA = new byte[0];
-
     private final MulticastSocket socket;
     private final DatagramChannelConfig config;
-    private final java.net.DatagramPacket tmpPacket = new java.net.DatagramPacket(EMPTY_DATA, 0);
+    private final java.net.DatagramPacket tmpPacket = new java.net.DatagramPacket(EmptyArrays.EMPTY_BYTES, 0);
 
     private static MulticastSocket newSocket() {
         try {