Add executor() to ChannelOutboundInvoker and let it replace eventLoop() (#11617)

Motivation:

We should just add `executor()` to the `ChannelOutboundInvoker` interface and override this method in `Channel` to return `EventLoop`.

Modifications:

- Add `executor()` method to `ChannelOutboundInvoker`
- Let `Channel` override this method and return `EventLoop`.
- Adjust all usages of `eventLoop()`
- Add some default implementations

Result:

API cleanup

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

@@ -358,7 +358,7 @@ public abstract class WebSocketClientHandshaker {
             // Delay the removal of the decoder so the user can setup the pipeline if needed to handle
             // WebSocketFrame messages.
             // See https://github.com/netty/netty/issues/4533
-            channel.eventLoop().execute(() -> p.remove(codec));
+            channel.executor().execute(() -> p.remove(codec));
         } else {
             if (p.get(HttpRequestEncoder.class) != null) {
                 // Remove the encoder part of the codec as the user may start writing frames after this method returns.
@@ -370,7 +370,7 @@ public abstract class WebSocketClientHandshaker {
             // Delay the removal of the decoder so the user can setup the pipeline if needed to handle
             // WebSocketFrame messages.
             // See https://github.com/netty/netty/issues/4533
-            channel.eventLoop().execute(() -> p.remove(context.handler()));
+            channel.executor().execute(() -> p.remove(context.handler()));
         }
     }
 
@@ -523,7 +523,7 @@ public abstract class WebSocketClientHandshaker {
             // Also, close might be called twice from different threads.
             if (future.isSuccess() && channel.isActive() &&
                     FORCE_CLOSE_INIT_UPDATER.compareAndSet(handshaker, 0, 1)) {
-                final Future<?> forceCloseFuture = channel.eventLoop().schedule(() -> {
+                final Future<?> forceCloseFuture = channel.executor().schedule(() -> {
                     if (channel.isActive()) {
                         channel.close();
                         forceCloseComplete = true;

codec-http/src/test/java/io/netty/handler/codec/http/HttpServerUpgradeHandlerTest.java

@@ -101,7 +101,7 @@ public class HttpServerUpgradeHandlerTest {
                 assertTrue(inReadCall);
                 writeUpgradeMessage = true;
                 Promise<Void> promise = ctx.newPromise();
-                ctx.channel().eventLoop().execute(() -> ctx.write(msg).addListener(new PromiseNotifier<>(promise)));
+                ctx.channel().executor().execute(() -> ctx.write(msg).addListener(new PromiseNotifier<>(promise)));
                 promise.addListener(f -> writeFlushed = true);
                 return promise;
             }

codec-http2/src/main/java/io/netty/handler/codec/http2/AbstractHttp2StreamChannel.java

@@ -256,7 +256,7 @@ abstract class AbstractHttp2StreamChannel extends DefaultAttributeMap implements
             if (task == null) {
                 fireChannelWritabilityChangedTask = task = pipeline::fireChannelWritabilityChanged;
             }
-            eventLoop().execute(task);
+            executor().execute(task);
         } else {
             pipeline.fireChannelWritabilityChanged();
         }
@@ -308,8 +308,8 @@ abstract class AbstractHttp2StreamChannel extends DefaultAttributeMap implements
     }
 
     @Override
-    public EventLoop eventLoop() {
+    public EventLoop executor() {
-        return parent().eventLoop();
+        return parent().executor();
     }
 
     @Override
@@ -400,7 +400,7 @@ abstract class AbstractHttp2StreamChannel extends DefaultAttributeMap implements
      * channel.
      */
     void fireChildRead(Http2Frame frame) {
-        assert eventLoop().inEventLoop();
+        assert executor().inEventLoop();
         if (!isActive()) {
             ReferenceCountUtil.release(frame);
         } else if (readStatus != ReadStatus.IDLE) {
@@ -427,7 +427,7 @@ abstract class AbstractHttp2StreamChannel extends DefaultAttributeMap implements
     }
 
     void fireChildReadComplete() {
-        assert eventLoop().inEventLoop();
+        assert executor().inEventLoop();
         assert readStatus != ReadStatus.IDLE || !readCompletePending;
         unsafe.notifyReadComplete(unsafe.recvBufAllocHandle(), false);
     }
@@ -615,7 +615,7 @@ abstract class AbstractHttp2StreamChannel extends DefaultAttributeMap implements
                 //       -> handlerA.channelInactive() - (2) another inbound handler method called while in (1) yet
                 //
                 // which means the execution of two inbound handler methods of the same handler overlap undesirably.
-                eventLoop().execute(task);
+                executor().execute(task);
             } catch (RejectedExecutionException e) {
                 logger.warn("Can't invoke task later as EventLoop rejected it", e);
             }

codec-http2/src/main/java/io/netty/handler/codec/http2/Http2MultiplexCodec.java

@@ -118,7 +118,7 @@ public class Http2MultiplexCodec extends Http2FrameCodec {
 
     @Override
     public final void handlerAdded0(ChannelHandlerContext ctx) throws Exception {
-        if (ctx.executor() != ctx.channel().eventLoop()) {
+        if (ctx.executor() != ctx.channel().executor()) {
             throw new IllegalStateException("EventExecutor must be EventLoop of Channel");
         }
         this.ctx = ctx;

codec-http2/src/main/java/io/netty/handler/codec/http2/Http2MultiplexHandler.java

@@ -140,7 +140,7 @@ public final class Http2MultiplexHandler extends Http2ChannelDuplexHandler {
 
     @Override
     protected void handlerAdded0(ChannelHandlerContext ctx) {
-        if (ctx.executor() != ctx.channel().eventLoop()) {
+        if (ctx.executor() != ctx.channel().executor()) {
             throw new IllegalStateException("EventExecutor must be EventLoop of Channel");
         }
         this.ctx = ctx;

codec-http2/src/main/java/io/netty/handler/codec/http2/Http2StreamChannelBootstrap.java

@@ -102,7 +102,7 @@ public final class Http2StreamChannelBootstrap {
      * @return the {@link Future} that will be notified once the channel was opened successfully or it failed.
      */
     public Future<Http2StreamChannel> open() {
-        return open(channel.eventLoop().newPromise());
+        return open(channel.executor().newPromise());
     }
 
     /**

codec-http2/src/test/java/io/netty/handler/codec/http2/Http2ClientUpgradeCodecTest.java

@@ -71,7 +71,7 @@ public class Http2ClientUpgradeCodecTest {
         // Flush the channel to ensure we write out all buffered data
         channel.flush();
 
-        channel.eventLoop().submit(() -> {
+        channel.executor().submit(() -> {
             codec.upgradeTo(ctx, null);
             return null;
         }).sync();

codec-http2/src/test/java/io/netty/handler/codec/http2/Http2FrameCodecTest.java

@@ -224,7 +224,7 @@ public class Http2FrameCodecTest {
         EmbeddedChannel em = new EmbeddedChannel(codec);
 
         AtomicReference<Http2Exception> errorRef = new AtomicReference<>();
-        em.eventLoop().execute(() -> {
+        em.executor().execute(() -> {
             try {
                 // We call #consumeBytes on a stream id which has not been seen yet to emulate the case
                 // where a stream is deregistered which in reality can happen in response to a RST.
@@ -545,7 +545,7 @@ public class Http2FrameCodecTest {
         int connectionWindowSizeBefore = localFlow.windowSize(connectionStream);
 
         AtomicReference<Http2Exception> errorRef = new AtomicReference<>();
-        channel.eventLoop().execute(() -> {
+        channel.executor().execute(() -> {
             try {
                 // We only replenish the flow control window after the amount consumed drops below the following
                 // threshold. We make the threshold very "high" so that window updates will be sent when the delta is
@@ -728,7 +728,7 @@ public class Http2FrameCodecTest {
     public void streamIdentifiersExhausted() throws Exception {
         int maxServerStreamId = Integer.MAX_VALUE - 1;
 
-        channel.eventLoop().submit(() -> {
+        channel.executor().submit(() -> {
             assertNotNull(frameCodec.connection().local().createStream(maxServerStreamId, false));
             return null;
         }).sync();
@@ -807,7 +807,7 @@ public class Http2FrameCodecTest {
 
         final Set<Http2FrameStream> activeStreams = new HashSet<>();
         final AtomicReference<Http2Exception> errorRef = new AtomicReference<>();
-        channel.eventLoop().execute(() -> {
+        channel.executor().execute(() -> {
             try {
                 frameCodec.forEachActiveStream(stream -> {
                     activeStreams.add(stream);

codec-http2/src/test/java/io/netty/handler/codec/http2/Http2FrameInboundWriter.java

@@ -119,7 +119,7 @@ final class Http2FrameInboundWriter {
 
         @Override
         public EventExecutor executor() {
-            return channel.eventLoop();
+            return channel.executor();
         }
 
         @Override

codec-http2/src/test/java/io/netty/handler/codec/http2/Http2MultiplexClientUpgradeTest.java

@@ -66,7 +66,7 @@ public abstract class Http2MultiplexClientUpgradeTest<C extends Http2FrameCodec>
         C codec = newCodec(upgradeHandler);
         EmbeddedChannel ch = new EmbeddedChannel(codec, newMultiplexer(upgradeHandler));
 
-        ch.eventLoop().submit(() -> {
+        ch.executor().submit(() -> {
             codec.onHttpClientUpgrade();
             return null;
         }).sync();

codec-http2/src/test/java/io/netty/handler/codec/http2/Http2MultiplexTransportTest.java

@@ -222,7 +222,7 @@ public class Http2MultiplexTransportTest {
                                         ctx.write(new DefaultHttp2DataFrame(
                                                 Unpooled.copiedBuffer("Hello World",
                                                                       CharsetUtil.US_ASCII), true));
-                                        ctx.channel().eventLoop().execute(ctx::flush);
+                                        ctx.channel().executor().execute(ctx::flush);
                                     });
                                 }, 500, MILLISECONDS);
                             }

codec-http2/src/test/java/io/netty/handler/codec/http2/Http2ServerUpgradeCodecTest.java

@@ -75,7 +75,7 @@ public class Http2ServerUpgradeCodecTest {
         } else {
             codec = new Http2ServerUpgradeCodec((Http2FrameCodec) handler, multiplexer);
         }
-        channel.eventLoop().execute(() -> {
+        channel.executor().execute(() -> {
             assertTrue(codec.prepareUpgradeResponse(ctx, request, new DefaultHttpHeaders()));
             codec.upgradeTo(ctx, request);
         });

codec-http2/src/test/java/io/netty/handler/codec/http2/Http2StreamChannelBootstrapTest.java

@@ -93,7 +93,7 @@ public class Http2StreamChannelBootstrapTest {
             assertTrue(serverChannelLatch.await(3, SECONDS));
 
             Http2StreamChannelBootstrap bootstrap = new Http2StreamChannelBootstrap(clientChannel);
-            final Promise<Http2StreamChannel> promise = clientChannel.eventLoop().newPromise();
+            final Promise<Http2StreamChannel> promise = clientChannel.executor().newPromise();
             clientChannel.close().sync();
 
             bootstrap.open(promise);

codec-http2/src/test/java/io/netty/handler/codec/http2/Http2TestUtil.java

@@ -20,7 +20,6 @@ import io.netty.buffer.Unpooled;
 import io.netty.buffer.UnpooledByteBufAllocator;
 import io.netty.channel.Channel;
 import io.netty.channel.ChannelHandlerContext;
-import io.netty.handler.codec.ByteToMessageDecoder;
 import io.netty.util.AsciiString;
 import io.netty.util.ReferenceCountUtil;
 import io.netty.util.concurrent.Future;
@@ -63,7 +62,7 @@ public final class Http2TestUtil {
      * Runs the given operation within the event loop thread of the given {@link Channel}.
      */
     static void runInChannel(Channel channel, final Http2Runnable runnable) {
-        channel.eventLoop().execute(() -> {
+        channel.executor().execute(() -> {
             try {
                 runnable.run();
             } catch (Http2Exception e) {

codec/src/test/java/io/netty/handler/codec/compression/Lz4FrameEncoderTest.java

@@ -272,7 +272,7 @@ public class Lz4FrameEncoderTest extends AbstractEncoderTest {
             clientChannel = bs.connect(serverChannel.localAddress()).get();
 
             final Channel finalClientChannel = clientChannel;
-            clientChannel.eventLoop().execute(() -> {
+            clientChannel.executor().execute(() -> {
                 finalClientChannel.close();
                 final int size = 27;
                 ByteBuf buf = ByteBufAllocator.DEFAULT.buffer(size, size);

example/src/main/java/io/netty/example/proxy/HexDumpProxyFrontendHandler.java

@@ -44,7 +44,7 @@ public class HexDumpProxyFrontendHandler implements ChannelHandler {
 
         // Start the connection attempt.
         Bootstrap b = new Bootstrap();
-        b.group(inboundChannel.eventLoop())
+        b.group(inboundChannel.executor())
          .channel(ctx.channel().getClass())
          .handler(new ChannelInitializer<Channel>() {
              @Override

example/src/main/java/io/netty/example/socksproxy/SocksServerConnectHandler.java

@@ -61,7 +61,7 @@ public final class SocksServerConnectHandler extends SimpleChannelInboundHandler
                     });
 
             final Channel inboundChannel = ctx.channel();
-            b.group(inboundChannel.eventLoop())
+            b.group(inboundChannel.executor())
                     .channel(NioSocketChannel.class)
                     .option(ChannelOption.CONNECT_TIMEOUT_MILLIS, 10000)
                     .option(ChannelOption.SO_KEEPALIVE, true)
@@ -104,7 +104,7 @@ public final class SocksServerConnectHandler extends SimpleChannelInboundHandler
                     });
 
             final Channel inboundChannel = ctx.channel();
-            b.group(inboundChannel.eventLoop())
+            b.group(inboundChannel.executor())
                     .channel(NioSocketChannel.class)
                     .option(ChannelOption.CONNECT_TIMEOUT_MILLIS, 10000)
                     .option(ChannelOption.SO_KEEPALIVE, true)

example/src/main/java/io/netty/example/uptime/UptimeClientHandler.java

@@ -68,7 +68,7 @@ public class UptimeClientHandler extends SimpleChannelInboundHandler<Object> {
     public void channelUnregistered(final ChannelHandlerContext ctx) throws Exception {
         println("Sleeping for: " + UptimeClient.RECONNECT_DELAY + 's');
 
-        ctx.channel().eventLoop().schedule(() -> {
+        ctx.channel().executor().schedule(() -> {
             println("Reconnecting to: " + UptimeClient.HOST + ':' + UptimeClient.PORT);
             UptimeClient.connect();
         }, UptimeClient.RECONNECT_DELAY, TimeUnit.SECONDS);

handler-proxy/src/test/java/io/netty/handler/proxy/ProxyServer.java

@@ -167,7 +167,7 @@ abstract class ProxyServer {
             boolean finished = handleProxyProtocol(ctx, msg);
             if (finished) {
                 this.finished = true;
-                Future<Channel> f = connectToDestination(ctx.channel().eventLoop(), new BackendHandler(ctx));
+                Future<Channel> f = connectToDestination(ctx.channel().executor(), new BackendHandler(ctx));
                 f.addListener(future -> {
                     if (!future.isSuccess()) {
                         recordException(future.cause());

handler/src/main/java/io/netty/handler/flush/FlushConsolidationHandler.java

@@ -199,7 +199,7 @@ public class FlushConsolidationHandler implements ChannelHandler {
     private void scheduleFlush(final ChannelHandlerContext ctx) {
         if (nextScheduledFlush == null) {
             // Run as soon as possible, but still yield to give a chance for additional writes to enqueue.
-            nextScheduledFlush = ctx.channel().eventLoop().submit(flushTask);
+            nextScheduledFlush = ctx.channel().executor().submit(flushTask);
         }
     }
 

handler/src/test/java/io/netty/handler/flow/FlowControlHandlerTest.java

@@ -505,7 +505,7 @@ public class FlowControlHandlerTest {
                 if (num >= 3) {
                     //We have received 3 messages. Remove myself later
                     final ChannelHandler handler = this;
-                    ctx.channel().eventLoop().execute(new Runnable() {
+                    ctx.channel().executor().execute(new Runnable() {
                         @Override
                         public void run() {
                             ctx.pipeline().remove(handler);

handler/src/test/java/io/netty/handler/flush/FlushConsolidationHandlerTest.java

@@ -36,7 +36,7 @@ public class FlushConsolidationHandlerTest {
     public void testFlushViaScheduledTask() {
         final AtomicInteger flushCount = new AtomicInteger();
         EmbeddedChannel channel = newChannel(flushCount,  true);
-        channel.eventLoop().execute(() -> {
+        channel.executor().execute(() -> {
             // Flushes should not go through immediately, as they're scheduled as an async task
             channel.flush();
             assertEquals(0, flushCount.get());
@@ -51,7 +51,7 @@ public class FlushConsolidationHandlerTest {
     public void testFlushViaThresholdOutsideOfReadLoop() {
         final AtomicInteger flushCount = new AtomicInteger();
         EmbeddedChannel channel = newChannel(flushCount, true);
-        channel.eventLoop().execute(() -> {
+        channel.executor().execute(() -> {
             // After a given threshold, the async task should be bypassed and a flush should be triggered immediately
             for (int i = 0; i < EXPLICIT_FLUSH_AFTER_FLUSHES; i++) {
                 channel.flush();

handler/src/test/java/io/netty/handler/ssl/SSLEngineTest.java

@@ -1493,7 +1493,7 @@ public abstract class SSLEngineTest {
                                 // The server then attempts to trigger a flush operation once the application data is
                                 // received from the client. The flush will encrypt all data and should not result in
                                 // deadlock.
-                                ctx.channel().eventLoop().schedule(() -> {
+                                ctx.channel().executor().schedule(() -> {
                                     ctx.writeAndFlush(ctx.alloc().buffer(1).writeByte(101));
                                 }, 500, TimeUnit.MILLISECONDS);
                             }

handler/src/test/java/io/netty/handler/ssl/SslHandlerTest.java

@@ -514,11 +514,11 @@ public class SslHandlerTest {
                 sslHandler.setHandshakeTimeoutMillis(1000);
                 ch.pipeline().addFirst(sslHandler);
                 sslHandler.handshakeFuture().addListener(future -> {
-                    ch.eventLoop().execute(() -> {
+                    ch.executor().execute(() -> {
                         ch.pipeline().remove(sslHandler);
 
                         // Schedule the close so removal has time to propagate exception if any.
-                        ch.eventLoop().execute(ch::close);
+                        ch.executor().execute(ch::close);
                     });
                 });
 

handler/src/test/java/io/netty/handler/traffic/TrafficShapingHandlerTest.java

@@ -106,7 +106,7 @@ public class TrafficShapingHandlerTest {
             ch.writeAndFlush(Unpooled.wrappedBuffer("bar".getBytes(CharsetUtil.UTF_8))).await();
             assertNotNull(attr.get());
             final Channel clientChannel = ch;
-            ch.eventLoop().submit(() -> {
+            ch.executor().submit(() -> {
                 clientChannel.pipeline().remove("traffic-shaping");
             }).await();
             //the attribute--reopen task must be released.

microbench/src/main/java/io/netty/microbench/channel/EmbeddedChannelHandlerContext.java

@@ -44,7 +44,7 @@ public abstract class EmbeddedChannelHandlerContext implements ChannelHandlerCon
         this.alloc = requireNonNull(alloc, "alloc");
         this.channel = requireNonNull(channel, "channel");
         this.handler = requireNonNull(handler, "handler");
-        eventLoop = requireNonNull(channel.eventLoop(), "eventLoop");
+        eventLoop = requireNonNull(channel.executor(), "eventLoop");
     }
 
     protected abstract void handleException(Throwable t);

microbench/src/main/java/io/netty/microbench/channel/epoll/EpollSocketChannelBenchmark.java

@@ -139,12 +139,12 @@ public class EpollSocketChannelBenchmark extends AbstractMicrobenchmark {
 
     @Benchmark
     public Object executeSingle() throws Exception {
-        return chan.eventLoop().submit(runnable).get();
+        return chan.executor().submit(runnable).get();
     }
 
     @Benchmark
     @GroupThreads(3)
     public Object executeMulti() throws Exception {
-        return chan.eventLoop().submit(runnable).get();
+        return chan.executor().submit(runnable).get();
     }
 }

resolver-dns/src/main/java/io/netty/resolver/dns/DnsAddressResolveContext.java

@@ -79,12 +79,12 @@ final class DnsAddressResolveContext extends DnsResolveContext<InetAddress> {
     @Override
     void cache(String hostname, DnsRecord[] additionals,
                DnsRecord result, InetAddress convertedResult) {
-        resolveCache.cache(hostname, additionals, convertedResult, result.timeToLive(), parent.ch.eventLoop());
+        resolveCache.cache(hostname, additionals, convertedResult, result.timeToLive(), parent.ch.executor());
     }
 
     @Override
     void cache(String hostname, DnsRecord[] additionals, UnknownHostException cause) {
-        resolveCache.cache(hostname, additionals, cause, parent.ch.eventLoop());
+        resolveCache.cache(hostname, additionals, cause, parent.ch.executor());
     }
 
     @Override

resolver-dns/src/main/java/io/netty/resolver/dns/DnsNameResolver.java

@@ -1157,7 +1157,7 @@ public class DnsNameResolver extends InetNameResolver {
             InetSocketAddress nameServerAddr, DnsQuestion question) {
 
         return query0(nameServerAddr, question, EMPTY_ADDITIONALS, true, ch.newPromise(),
-                      ch.eventLoop().newPromise());
+                      ch.executor().newPromise());
     }
 
     /**
@@ -1167,7 +1167,7 @@ public class DnsNameResolver extends InetNameResolver {
             InetSocketAddress nameServerAddr, DnsQuestion question, Iterable<DnsRecord> additionals) {
 
         return query0(nameServerAddr, question, toArray(additionals, false), true, ch.newPromise(),
-                     ch.eventLoop().newPromise());
+                     ch.executor().newPromise());
     }
 
     /**
@@ -1288,7 +1288,7 @@ public class DnsNameResolver extends InetNameResolver {
                 final Channel channel = future.getNow();
 
                 Promise<AddressedEnvelope<DnsResponse, InetSocketAddress>> promise =
-                        channel.eventLoop().newPromise();
+                        channel.executor().newPromise();
                 final TcpDnsQueryContext tcpCtx = new TcpDnsQueryContext(DnsNameResolver.this, channel,
                         (InetSocketAddress) channel.remoteAddress(), qCtx.question(),
                         EMPTY_ADDITIONALS, promise);

resolver-dns/src/main/java/io/netty/resolver/dns/DnsQueryContext.java

@@ -156,7 +156,7 @@ abstract class DnsQueryContext implements FutureListener<AddressedEnvelope<DnsRe
         // Schedule a query timeout task if necessary.
         final long queryTimeoutMillis = parent.queryTimeoutMillis();
         if (queryTimeoutMillis > 0) {
-            timeoutFuture = parent.ch.eventLoop().schedule(() -> {
+            timeoutFuture = parent.ch.executor().schedule(() -> {
                 if (promise.isDone()) {
                     // Received a response before the query times out.
                     return;

resolver-dns/src/main/java/io/netty/resolver/dns/DnsResolveContext.java

@@ -414,7 +414,7 @@ abstract class DnsResolveContext<T> {
         }
         final Promise<Void> writePromise = parent.ch.newPromise();
         final Promise<AddressedEnvelope<? extends DnsResponse, InetSocketAddress>> queryPromise =
-                parent.ch.eventLoop().newPromise();
+                parent.ch.executor().newPromise();
 
         final Future<AddressedEnvelope<DnsResponse, InetSocketAddress>> f =
                 parent.query0(nameServerAddr, question, additionals, flush, writePromise, queryPromise);

resolver-dns/src/test/java/io/netty/resolver/dns/DnsResolveContextTest.java

@@ -42,15 +42,15 @@ public class DnsResolveContextTest {
         EmbeddedChannel channel = new EmbeddedChannel();
         DnsCnameCache cache = new DefaultDnsCnameCache();
         if (chainLength == 1) {
-            cache.cache(HOSTNAME, HOSTNAME, Long.MAX_VALUE, channel.eventLoop());
+            cache.cache(HOSTNAME, HOSTNAME, Long.MAX_VALUE, channel.executor());
         } else {
             String lastName = HOSTNAME;
             for (int i = 1; i < chainLength; i++) {
                 String nextName = i + "." + lastName;
-                cache.cache(lastName, nextName, Long.MAX_VALUE, channel.eventLoop());
+                cache.cache(lastName, nextName, Long.MAX_VALUE, channel.executor());
                 lastName = nextName;
             }
-            cache.cache(lastName, HOSTNAME, Long.MAX_VALUE, channel.eventLoop());
+            cache.cache(lastName, HOSTNAME, Long.MAX_VALUE, channel.executor());
         }
         return cache;
     }

testsuite/src/main/java/io/netty/testsuite/transport/socket/SocketCloseForciblyTest.java

@@ -37,7 +37,7 @@ public class SocketCloseForciblyTest extends AbstractSocketTest {
             public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
                 final SocketChannel childChannel = (SocketChannel) msg;
                 // Dispatch on the EventLoop as all operation on Unsafe should be done while on the EventLoop.
-                childChannel.eventLoop().execute(() -> {
+                childChannel.executor().execute(() -> {
                     childChannel.config().setSoLinger(0);
                     childChannel.unsafe().closeForcibly();
                 });

testsuite/src/main/java/io/netty/testsuite/transport/socket/SocketHalfClosedTest.java

@@ -326,7 +326,7 @@ public class SocketHalfClosedTest extends AbstractSocketTest {
                     // but the close will be done after the Selector did process all events. Because of
                     // this we will need to give it a bit time to ensure the FD is actual closed before we
                     // count down the latch and try to write.
-                    channel.eventLoop().schedule(followerCloseLatch::countDown, 200, MILLISECONDS);
+                    channel.executor().schedule(followerCloseLatch::countDown, 200, MILLISECONDS);
                 }));
             }
         }

transport-native-epoll/src/main/java/io/netty/channel/epoll/AbstractEpollChannel.java

@@ -175,7 +175,7 @@ abstract class AbstractEpollChannel extends AbstractChannel implements UnixChann
                 // if SO_LINGER is used.
                 //
                 // See https://github.com/netty/netty/issues/7159
-                EventLoop loop = eventLoop();
+                EventLoop loop = executor();
                 if (loop.inEventLoop()) {
                     doDeregister();
                 } else {
@@ -255,7 +255,7 @@ abstract class AbstractEpollChannel extends AbstractChannel implements UnixChann
     final void clearEpollIn() {
         // Only clear if registered with an EventLoop as otherwise
         if (isRegistered()) {
-            final EventLoop loop = eventLoop();
+            final EventLoop loop = executor();
             final AbstractEpollUnsafe unsafe = (AbstractEpollUnsafe) unsafe();
             if (loop.inEventLoop()) {
                 unsafe.clearEpollIn0();
@@ -456,7 +456,7 @@ abstract class AbstractEpollChannel extends AbstractChannel implements UnixChann
                 return;
             }
             epollInReadyRunnablePending = true;
-            eventLoop().execute(epollInReadyRunnable);
+            executor().execute(epollInReadyRunnable);
         }
 
         /**
@@ -565,7 +565,7 @@ abstract class AbstractEpollChannel extends AbstractChannel implements UnixChann
         }
 
         protected final void clearEpollIn0() {
-            assert eventLoop().inEventLoop();
+            assert executor().inEventLoop();
             try {
                 readPending = false;
                 clearFlag(Native.EPOLLIN);
@@ -599,7 +599,7 @@ abstract class AbstractEpollChannel extends AbstractChannel implements UnixChann
                     // Schedule connect timeout.
                     int connectTimeoutMillis = config().getConnectTimeoutMillis();
                     if (connectTimeoutMillis > 0) {
-                        connectTimeoutFuture = eventLoop().schedule(() -> {
+                        connectTimeoutFuture = executor().schedule(() -> {
                             Promise<Void> connectPromise = AbstractEpollChannel.this.connectPromise;
                             if (connectPromise != null && !connectPromise.isDone()
                                     && connectPromise.tryFailure(new ConnectTimeoutException(
@@ -667,7 +667,7 @@ abstract class AbstractEpollChannel extends AbstractChannel implements UnixChann
             // Note this method is invoked by the event loop only if the connection attempt was
             // neither cancelled nor timed out.
 
-            assert eventLoop().inEventLoop();
+            assert executor().inEventLoop();
 
             boolean connectStillInProgress = false;
             try {

transport-native-epoll/src/main/java/io/netty/channel/epoll/AbstractEpollServerChannel.java

@@ -95,7 +95,7 @@ public abstract class AbstractEpollServerChannel extends AbstractEpollChannel im
 
         @Override
         void epollInReady() {
-            assert eventLoop().inEventLoop();
+            assert executor().inEventLoop();
             final ChannelConfig config = config();
             if (shouldBreakEpollInReady(config)) {
                 clearEpollIn0();

transport-native-epoll/src/main/java/io/netty/channel/epoll/AbstractEpollStreamChannel.java

@@ -312,7 +312,7 @@ public abstract class AbstractEpollStreamChannel extends AbstractEpollChannel im
             clearFlag(Native.EPOLLOUT);
 
             // We used our writeSpin quantum, and should try to write again later.
-            eventLoop().execute(flushTask);
+            executor().execute(flushTask);
         } else {
             // Underlying descriptor can not accept all data currently, so set the EPOLLOUT flag to be woken up
             // when it can accept more data.
@@ -430,7 +430,7 @@ public abstract class AbstractEpollStreamChannel extends AbstractEpollChannel im
 
     @Override
     public Future<Void> shutdownOutput(final Promise<Void> promise) {
-        EventLoop loop = eventLoop();
+        EventLoop loop = executor();
         if (loop.inEventLoop()) {
             ((AbstractUnsafe) unsafe()).shutdownOutput(promise);
         } else {
@@ -451,7 +451,7 @@ public abstract class AbstractEpollStreamChannel extends AbstractEpollChannel im
         if (closeExecutor != null) {
             closeExecutor.execute(() -> shutdownInput0(promise));
         } else {
-            EventLoop loop = eventLoop();
+            EventLoop loop = executor();
             if (loop.inEventLoop()) {
                 shutdownInput0(promise);
             } else {

transport-native-epoll/src/main/java/io/netty/channel/epoll/EpollDatagramChannel.java

@@ -459,7 +459,7 @@ public final class EpollDatagramChannel extends AbstractEpollChannel implements
 
         @Override
         void epollInReady() {
-            assert eventLoop().inEventLoop();
+            assert executor().inEventLoop();
             EpollDatagramChannelConfig config = config();
             if (shouldBreakEpollInReady(config)) {
                 clearEpollIn0();

transport-native-epoll/src/main/java/io/netty/channel/epoll/EpollDomainDatagramChannel.java

@@ -292,7 +292,7 @@ public final class EpollDomainDatagramChannel extends AbstractEpollChannel imple
 
         @Override
         void epollInReady() {
-            assert eventLoop().inEventLoop();
+            assert executor().inEventLoop();
             final DomainDatagramChannelConfig config = config();
             if (shouldBreakEpollInReady(config)) {
                 clearEpollIn0();

transport-native-epoll/src/test/java/io/netty/channel/epoll/EpollDomainSocketFdTest.java

@@ -62,7 +62,7 @@ public class EpollDomainSocketFdTest extends AbstractSocketTest {
             @Override
             public void channelActive(ChannelHandlerContext ctx) throws Exception {
                 // Create new channel and obtain a file descriptor from it.
-                final EpollDomainSocketChannel ch = new EpollDomainSocketChannel(ctx.channel().eventLoop());
+                final EpollDomainSocketChannel ch = new EpollDomainSocketChannel(ctx.channel().executor());
 
                 ctx.writeAndFlush(ch.fd()).addListener(future -> {
                     if (!future.isSuccess()) {

transport-native-kqueue/src/main/java/io/netty/channel/kqueue/AbstractKQueueChannel.java

@@ -308,7 +308,7 @@ abstract class AbstractKQueueChannel extends AbstractChannel implements UnixChan
     final void clearReadFilter() {
         // Only clear if registered with an EventLoop as otherwise
         if (isRegistered()) {
-            final EventLoop loop = eventLoop();
+            final EventLoop loop = executor();
             final AbstractKQueueUnsafe unsafe = (AbstractKQueueUnsafe) unsafe();
             if (loop.inEventLoop()) {
                 unsafe.clearReadFilter0();
@@ -507,11 +507,11 @@ abstract class AbstractKQueueChannel extends AbstractChannel implements UnixChan
                 return;
             }
             readReadyRunnablePending = true;
-            eventLoop().execute(readReadyRunnable);
+            executor().execute(readReadyRunnable);
         }
 
         protected final void clearReadFilter0() {
-            assert eventLoop().inEventLoop();
+            assert executor().inEventLoop();
             try {
                 readPending = false;
                 readFilter(false);
@@ -550,7 +550,7 @@ abstract class AbstractKQueueChannel extends AbstractChannel implements UnixChan
                     // Schedule connect timeout.
                     int connectTimeoutMillis = config().getConnectTimeoutMillis();
                     if (connectTimeoutMillis > 0) {
-                        connectTimeoutFuture = eventLoop().schedule(() -> {
+                        connectTimeoutFuture = executor().schedule(() -> {
                             Promise<Void> connectPromise = AbstractKQueueChannel.this.connectPromise;
                             if (connectPromise != null && !connectPromise.isDone()
                                     && connectPromise.tryFailure(new ConnectTimeoutException(
@@ -618,7 +618,7 @@ abstract class AbstractKQueueChannel extends AbstractChannel implements UnixChan
             // Note this method is invoked by the event loop only if the connection attempt was
             // neither cancelled nor timed out.
 
-            assert eventLoop().inEventLoop();
+            assert executor().inEventLoop();
 
             boolean connectStillInProgress = false;
             try {

transport-native-kqueue/src/main/java/io/netty/channel/kqueue/AbstractKQueueServerChannel.java

@@ -89,7 +89,7 @@ public abstract class AbstractKQueueServerChannel extends AbstractKQueueChannel
 
         @Override
         void readReady(KQueueRecvByteAllocatorHandle allocHandle) {
-            assert eventLoop().inEventLoop();
+            assert executor().inEventLoop();
             final ChannelConfig config = config();
             if (shouldBreakReadReady(config)) {
                 clearReadFilter0();

transport-native-kqueue/src/main/java/io/netty/channel/kqueue/AbstractKQueueStreamChannel.java

@@ -294,7 +294,7 @@ public abstract class AbstractKQueueStreamChannel extends AbstractKQueueChannel
             writeFilter(false);
 
             // We used our writeSpin quantum, and should try to write again later.
-            eventLoop().execute(flushTask);
+            executor().execute(flushTask);
         } else {
             // Underlying descriptor can not accept all data currently, so set the WRITE flag to be woken up
             // when it can accept more data.
@@ -403,7 +403,7 @@ public abstract class AbstractKQueueStreamChannel extends AbstractKQueueChannel
 
     @Override
     public Future<Void> shutdownOutput(final Promise<Void> promise) {
-        EventLoop loop = eventLoop();
+        EventLoop loop = executor();
         if (loop.inEventLoop()) {
             ((AbstractUnsafe) unsafe()).shutdownOutput(promise);
         } else {
@@ -419,7 +419,7 @@ public abstract class AbstractKQueueStreamChannel extends AbstractKQueueChannel
 
     @Override
     public Future<Void> shutdownInput(final Promise<Void> promise) {
-        EventLoop loop = eventLoop();
+        EventLoop loop = executor();
         if (loop.inEventLoop()) {
             shutdownInput0(promise);
         } else {

transport-native-kqueue/src/main/java/io/netty/channel/kqueue/KQueueDatagramChannel.java

@@ -352,7 +352,7 @@ public final class KQueueDatagramChannel extends AbstractKQueueDatagramChannel i
 
         @Override
         void readReady(KQueueRecvByteAllocatorHandle allocHandle) {
-            assert eventLoop().inEventLoop();
+            assert executor().inEventLoop();
             final DatagramChannelConfig config = config();
             if (shouldBreakReadReady(config)) {
                 clearReadFilter0();

transport-native-kqueue/src/main/java/io/netty/channel/kqueue/KQueueDomainDatagramChannel.java

@@ -241,7 +241,7 @@ public final class KQueueDomainDatagramChannel extends AbstractKQueueDatagramCha
 
         @Override
         void readReady(KQueueRecvByteAllocatorHandle allocHandle) {
-            assert eventLoop().inEventLoop();
+            assert executor().inEventLoop();
             final DomainDatagramChannelConfig config = config();
             if (shouldBreakReadReady(config)) {
                 clearReadFilter0();

transport-native-kqueue/src/test/java/io/netty/channel/kqueue/KQueueDomainSocketFdTest.java

@@ -62,7 +62,7 @@ public class KQueueDomainSocketFdTest extends AbstractSocketTest {
             @Override
             public void channelActive(ChannelHandlerContext ctx) throws Exception {
                 // Create new channel and obtain a file descriptor from it.
-                final KQueueDomainSocketChannel ch = new KQueueDomainSocketChannel(ctx.channel().eventLoop());
+                final KQueueDomainSocketChannel ch = new KQueueDomainSocketChannel(ctx.channel().executor());
 
                 ctx.writeAndFlush(ch.fd()).addListener(future -> {
                     if (!future.isSuccess()) {

transport-sctp/src/main/java/io/netty/channel/sctp/nio/NioSctpChannel.java

@@ -342,7 +342,7 @@ public class NioSctpChannel extends AbstractNioMessageChannel implements io.nett
 
     @Override
     public Future<Void> bindAddress(final InetAddress localAddress, final Promise<Void> promise) {
-        if (eventLoop().inEventLoop()) {
+        if (executor().inEventLoop()) {
             try {
                 javaChannel().bindAddress(localAddress);
                 promise.setSuccess(null);
@@ -350,7 +350,7 @@ public class NioSctpChannel extends AbstractNioMessageChannel implements io.nett
                 promise.setFailure(t);
             }
         } else {
-            eventLoop().execute(() -> bindAddress(localAddress, promise));
+            executor().execute(() -> bindAddress(localAddress, promise));
         }
         return promise;
     }
@@ -362,7 +362,7 @@ public class NioSctpChannel extends AbstractNioMessageChannel implements io.nett
 
     @Override
     public Future<Void> unbindAddress(final InetAddress localAddress, final Promise<Void> promise) {
-        if (eventLoop().inEventLoop()) {
+        if (executor().inEventLoop()) {
             try {
                 javaChannel().unbindAddress(localAddress);
                 promise.setSuccess(null);
@@ -370,7 +370,7 @@ public class NioSctpChannel extends AbstractNioMessageChannel implements io.nett
                 promise.setFailure(t);
             }
         } else {
-            eventLoop().execute(() -> unbindAddress(localAddress, promise));
+            executor().execute(() -> unbindAddress(localAddress, promise));
         }
         return promise;
     }

transport-sctp/src/main/java/io/netty/channel/sctp/nio/NioSctpServerChannel.java

@@ -162,7 +162,7 @@ public class NioSctpServerChannel extends AbstractNioMessageChannel
 
     @Override
     public Future<Void> bindAddress(final InetAddress localAddress, final Promise<Void> promise) {
-        if (eventLoop().inEventLoop()) {
+        if (executor().inEventLoop()) {
             try {
                 javaChannel().bindAddress(localAddress);
                 promise.setSuccess(null);
@@ -170,7 +170,7 @@ public class NioSctpServerChannel extends AbstractNioMessageChannel
                 promise.setFailure(t);
             }
         } else {
-            eventLoop().execute(() -> bindAddress(localAddress, promise));
+            executor().execute(() -> bindAddress(localAddress, promise));
         }
         return promise;
     }
@@ -182,7 +182,7 @@ public class NioSctpServerChannel extends AbstractNioMessageChannel
 
     @Override
     public Future<Void> unbindAddress(final InetAddress localAddress, final Promise<Void> promise) {
-        if (eventLoop().inEventLoop()) {
+        if (executor().inEventLoop()) {
             try {
                 javaChannel().unbindAddress(localAddress);
                 promise.setSuccess(null);
@@ -190,7 +190,7 @@ public class NioSctpServerChannel extends AbstractNioMessageChannel
                 promise.setFailure(t);
             }
         } else {
-            eventLoop().execute(() -> unbindAddress(localAddress, promise));
+            executor().execute(() -> unbindAddress(localAddress, promise));
         }
         return promise;
     }

transport/src/main/java/io/netty/bootstrap/AbstractBootstrap.java

@@ -317,7 +317,7 @@ public abstract class AbstractBootstrap<B extends AbstractBootstrap<B, C, F>, C
             final SocketAddress localAddress, final Promise<Void> promise) {
         // This method is invoked before channelRegistered() is triggered.  Give user handlers a chance to set up
         // the pipeline in its channelRegistered() implementation.
-        channel.eventLoop().execute(() -> {
+        channel.executor().execute(() -> {
             if (regFuture.isSuccess()) {
                 PromiseNotifier.cascade(channel.bind(localAddress), promise)
                         .addListener(channel, ChannelFutureListeners.CLOSE_ON_FAILURE);

transport/src/main/java/io/netty/bootstrap/Bootstrap.java

@@ -217,7 +217,7 @@ public class Bootstrap extends AbstractBootstrap<Bootstrap, Channel, ChannelFact
     private void doResolveAndConnect0(final Channel channel, SocketAddress remoteAddress,
                                       final SocketAddress localAddress, final Promise<Channel> promise) {
         try {
-            final EventLoop eventLoop = channel.eventLoop();
+            final EventLoop eventLoop = channel.executor();
             final AddressResolver<SocketAddress> resolver = this.resolver.getResolver(eventLoop);
 
             if (!resolver.isSupported(remoteAddress) || resolver.isResolved(remoteAddress)) {
@@ -260,7 +260,7 @@ public class Bootstrap extends AbstractBootstrap<Bootstrap, Channel, ChannelFact
             SocketAddress remoteAddress, SocketAddress localAddress, Channel channel, Promise<Channel> promise) {
         // This method is invoked before channelRegistered() is triggered.  Give user handlers a chance to set up
         // the pipeline in its channelRegistered() implementation.
-        channel.eventLoop().execute(() -> {
+        channel.executor().execute(() -> {
             final Future<Void> future;
             if (localAddress == null) {
                 future = channel.connect(remoteAddress);
@@ -281,7 +281,7 @@ public class Bootstrap extends AbstractBootstrap<Bootstrap, Channel, ChannelFact
 
         p.addLast(config.handler());
 
-        return DefaultPromise.newSuccessfulPromise(channel.eventLoop(), channel);
+        return DefaultPromise.newSuccessfulPromise(channel.executor(), channel);
     }
 
     @Override

transport/src/main/java/io/netty/bootstrap/ServerBootstrap.java

@@ -165,7 +165,7 @@ public class ServerBootstrap extends AbstractBootstrap<ServerBootstrap, ServerCh
 
     @Override
     Future<Channel> init(Channel channel) {
-        Promise<Channel> promise = new DefaultPromise<>(channel.eventLoop());
+        Promise<Channel> promise = new DefaultPromise<>(channel.executor());
         setChannelOptions(channel, newOptionsArray(), logger);
         setAttributes(channel, newAttributesArray());
 
@@ -184,7 +184,7 @@ public class ServerBootstrap extends AbstractBootstrap<ServerBootstrap, ServerCh
                     pipeline.addLast(handler);
                 }
 
-                ch.eventLoop().execute(() -> {
+                ch.executor().execute(() -> {
                     pipeline.addLast(new ServerBootstrapAcceptor(
                             ch, currentChildHandler, currentChildOptions, currentChildAttrs));
                     promise.setSuccess(ch);
@@ -241,7 +241,7 @@ public class ServerBootstrap extends AbstractBootstrap<ServerBootstrap, ServerCh
         public void channelRead(ChannelHandlerContext ctx, Object msg) {
             final Channel child = (Channel) msg;
 
-            EventLoop childEventLoop = child.eventLoop();
+            EventLoop childEventLoop = child.executor();
             // Ensure we always execute on the child EventLoop.
             if (childEventLoop.inEventLoop()) {
                 initChild(child);
@@ -255,7 +255,7 @@ public class ServerBootstrap extends AbstractBootstrap<ServerBootstrap, ServerCh
         }
 
         private void initChild(final Channel child) {
-            assert child.eventLoop().inEventLoop();
+            assert child.executor().inEventLoop();
             try {
                 setChannelOptions(child, childOptions, logger);
                 setAttributes(child, childAttrs);
@@ -284,7 +284,7 @@ public class ServerBootstrap extends AbstractBootstrap<ServerBootstrap, ServerCh
                 // stop accept new connections for 1 second to allow the channel to recover
                 // See https://github.com/netty/netty/issues/1328
                 config.setAutoRead(false);
-                ctx.channel().eventLoop().schedule(enableAutoReadTask, 1, TimeUnit.SECONDS);
+                ctx.channel().executor().schedule(enableAutoReadTask, 1, TimeUnit.SECONDS);
             }
             // still let the exceptionCaught event flow through the pipeline to give the user
             // a chance to do something with it

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

@@ -145,7 +145,7 @@ public abstract class AbstractChannel extends DefaultAttributeMap implements Cha
     }
 
     @Override
-    public EventLoop eventLoop() {
+    public EventLoop executor() {
         return eventLoop;
     }
 
@@ -492,7 +492,7 @@ public abstract class AbstractChannel extends DefaultAttributeMap implements Cha
                         promise.setFailure(err);
                     } finally {
                         // Dispatch to the EventLoop
-                        eventLoop().execute(() ->
+                        executor().execute(() ->
                                 closeOutboundBufferForShutdown(pipeline, outboundBuffer, shutdownCause));
                     }
                 });
@@ -850,7 +850,7 @@ public abstract class AbstractChannel extends DefaultAttributeMap implements Cha
                 //         -> handlerA.channelInactive() - (2) another inbound handler method called while in (1) yet
                 //
                 // which means the execution of two inbound handler methods of the same handler overlap undesirably.
-                eventLoop().execute(task);
+                executor().execute(task);
             } catch (RejectedExecutionException e) {
                 logger.warn("Can't invoke task later as EventLoop rejected it", e);
             }
@@ -900,7 +900,7 @@ public abstract class AbstractChannel extends DefaultAttributeMap implements Cha
      * Sub-classes may override this method
      */
     protected void doRegister() throws Exception {
-        eventLoop().unsafe().register(this);
+        executor().unsafe().register(this);
     }
 
     /**
@@ -933,7 +933,7 @@ public abstract class AbstractChannel extends DefaultAttributeMap implements Cha
      * Sub-classes may override this method
      */
     protected void doDeregister() throws Exception {
-        eventLoop().unsafe().deregister(this);
+        executor().unsafe().deregister(this);
     }
 
     /**

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

@@ -86,7 +86,7 @@ public interface Channel extends AttributeMap, ChannelOutboundInvoker, Comparabl
     /**
      * Return the {@link EventLoop} this {@link Channel} was registered to.
      */
-    EventLoop eventLoop();
+    EventLoop executor();
 
     /**
      * Returns the parent of this channel.
@@ -261,21 +261,6 @@ public interface Channel extends AttributeMap, ChannelOutboundInvoker, Comparabl
         return this;
     }
 
-    @Override
-    default Promise<Void> newPromise() {
-        return eventLoop().newPromise();
-    }
-
-    @Override
-    default Future<Void> newSucceededFuture() {
-        return eventLoop().newSucceededFuture(null);
-    }
-
-    @Override
-    default Future<Void> newFailedFuture(Throwable cause) {
-        return eventLoop().newFailedFuture(cause);
-    }
-
     /**
      * <em>Unsafe</em> operations that should <em>never</em> be called from user-code. These methods
      * are only provided to implement the actual transport, and must be invoked from an I/O thread except for the

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

@@ -20,7 +20,6 @@ import io.netty.buffer.ByteBufAllocator;
 import io.netty.util.Attribute;
 import io.netty.util.AttributeKey;
 import io.netty.util.AttributeMap;
-import io.netty.util.concurrent.EventExecutor;
 
 /**
  * Enables a {@link ChannelHandler} to interact with its {@link ChannelPipeline}
@@ -104,11 +103,11 @@ import io.netty.util.concurrent.EventExecutor;
  * // calculated correctly 4 times once the two pipelines (p1 and p2) are active.
  * FactorialHandler fh = new FactorialHandler();
  *
- * {@link ChannelPipeline} p1 = {@link Channels}.pipeline();
+ * {@link ChannelPipeline} p1 = {@link Channel}.pipeline();
  * p1.addLast("f1", fh);
  * p1.addLast("f2", fh);
  *
- * {@link ChannelPipeline} p2 = {@link Channels}.pipeline();
+ * {@link ChannelPipeline} p2 = {@link Channel}.pipeline();
  * p2.addLast("f3", fh);
  * p2.addLast("f4", fh);
  * </pre>
@@ -127,11 +126,6 @@ public interface ChannelHandlerContext extends AttributeMap, ChannelInboundInvok
      */
     Channel channel();
 
-    /**
-     * Returns the {@link EventExecutor} which is used to execute an arbitrary task.
-     */
-    EventExecutor executor();
-
     /**
      * The unique name of the {@link ChannelHandlerContext}.The name was used when then {@link ChannelHandler}
      * was added to the {@link ChannelPipeline}. This name can also be used to access the registered

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

@@ -610,7 +610,7 @@ public final class ChannelOutboundBuffer {
             if (task == null) {
                 fireChannelWritabilityChangedTask = task = pipeline::fireChannelWritabilityChanged;
             }
-            channel.eventLoop().execute(task);
+            channel.executor().execute(task);
         } else {
             pipeline.fireChannelWritabilityChanged();
         }
@@ -655,7 +655,7 @@ public final class ChannelOutboundBuffer {
 
     void close(final Throwable cause, final boolean allowChannelOpen) {
         if (inFail) {
-            channel.eventLoop().execute(() -> close(cause, allowChannelOpen));
+            channel.executor().execute(() -> close(cause, allowChannelOpen));
             return;
         }
 

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

@@ -147,19 +147,32 @@ public interface ChannelOutboundInvoker {
     /**
      * Return a new {@link Promise}.
      */
-    Promise<Void> newPromise();
+    default Promise<Void> newPromise() {
+        return executor().newPromise();
+    }
 
     /**
      * Create a new {@link Future} which is marked as succeeded already. So {@link Future#isSuccess()}
      * will return {@code true}. All {@link FutureListener} added to it will be notified directly. Also
      * every call of blocking methods will just return without blocking.
      */
-    Future<Void> newSucceededFuture();
+    default Future<Void> newSucceededFuture() {
+        return executor().newSucceededFuture(null);
+    }
 
     /**
      * Create a new {@link Future} which is marked as failed already. So {@link Future#isSuccess()}
      * will return {@code false}. All {@link FutureListener} added to it will be notified directly. Also
      * every call of blocking methods will just return without blocking.
      */
-    Future<Void> newFailedFuture(Throwable cause);
+    default Future<Void> newFailedFuture(Throwable cause) {
+        return executor().newFailedFuture(cause);
+    }
+
+    /**
+     * Returns the {@link EventExecutor} that is used to execute the operations of this {@link ChannelOutboundInvoker}.
+     *
+     * @return  the executor.
+     */
+    EventExecutor executor();
 }

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

@@ -16,7 +16,6 @@
 package io.netty.channel;
 
 import io.netty.buffer.ByteBuf;
-import io.netty.util.concurrent.EventExecutor;
 import io.netty.util.concurrent.Promise;
 
 import java.net.SocketAddress;
@@ -538,9 +537,4 @@ public interface ChannelPipeline
 
     @Override
     ChannelPipeline flush();
-
-    /**
-     * Returns the {@link EventExecutor} which is used by all {@link ChannelHandler}s in the pipeline.
-     */
-    EventExecutor executor();
 }

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

@@ -78,7 +78,7 @@ public class DefaultChannelPipeline implements ChannelPipeline {
 
     public DefaultChannelPipeline(Channel channel) {
         this.channel = requireNonNull(channel, "channel");
-        succeededFuture = DefaultPromise.newSuccessfulPromise(channel.eventLoop(), null);
+        succeededFuture = DefaultPromise.newSuccessfulPromise(channel.executor(), null);
 
         tail = new DefaultChannelHandlerContext(this, TAIL_NAME, TAIL_HANDLER);
         head = new DefaultChannelHandlerContext(this, HEAD_NAME, HEAD_HANDLER);
@@ -132,7 +132,7 @@ public class DefaultChannelPipeline implements ChannelPipeline {
 
     @Override
     public final EventExecutor executor() {
-        return channel().eventLoop();
+        return channel().executor();
     }
 
     @Override

transport/src/main/java/io/netty/channel/embedded/EmbeddedChannel.java

@@ -520,7 +520,7 @@ public class EmbeddedChannel extends AbstractChannel {
         runPendingTasks();
         if (cancel) {
             // Cancel all scheduled tasks that are left.
-            ((EmbeddedEventLoop) eventLoop()).cancelScheduled();
+            ((EmbeddedEventLoop) executor()).cancelScheduled();
         }
     }
 
@@ -556,7 +556,7 @@ public class EmbeddedChannel extends AbstractChannel {
      * for this {@link Channel}
      */
     public void runPendingTasks() {
-        EmbeddedEventLoop embeddedEventLoop = (EmbeddedEventLoop) eventLoop();
+        EmbeddedEventLoop embeddedEventLoop = (EmbeddedEventLoop) executor();
         try {
             embeddedEventLoop.runTasks();
         } catch (Exception e) {
@@ -572,7 +572,7 @@ public class EmbeddedChannel extends AbstractChannel {
      * {@code -1}.
      */
     public long runScheduledPendingTasks() {
-        EmbeddedEventLoop embeddedEventLoop = (EmbeddedEventLoop) eventLoop();
+        EmbeddedEventLoop embeddedEventLoop = (EmbeddedEventLoop) executor();
 
         try {
             return embeddedEventLoop.runScheduledTasks();
@@ -746,7 +746,7 @@ public class EmbeddedChannel extends AbstractChannel {
             }
 
             private void mayRunPendingTasks() {
-                if (!((EmbeddedEventLoop) eventLoop()).running) {
+                if (!((EmbeddedEventLoop) executor()).running) {
                     runPendingTasks();
                 }
             }

transport/src/main/java/io/netty/channel/local/LocalChannel.java

@@ -186,7 +186,7 @@ public class LocalChannel extends AbstractChannel {
                 // Always call peer.eventLoop().execute() even if peer.eventLoop().inEventLoop() is true.
                 // This ensures that if both channels are on the same event loop, the peer's channelInActive
                 // event is triggered *after* this peer's channelInActive event
-                EventLoop peerEventLoop = peer.eventLoop();
+                EventLoop peerEventLoop = peer.executor();
                 final boolean peerIsActive = peer.isActive();
                 try {
                     peerEventLoop.execute(() -> peer.tryClose(peerIsActive));
@@ -269,7 +269,7 @@ public class LocalChannel extends AbstractChannel {
             }
         } else {
             try {
-                eventLoop().execute(readTask);
+                executor().execute(readTask);
             } catch (Throwable cause) {
                 logger.warn("Closing Local channels {}-{} because exception occurred!", this, peer, cause);
                 close();
@@ -331,7 +331,7 @@ public class LocalChannel extends AbstractChannel {
 
     private void finishPeerRead(final LocalChannel peer) {
         // If the peer is also writing, then we must schedule the event on the event loop to preserve read order.
-        if (peer.eventLoop() == eventLoop() && !peer.writeInProgress) {
+        if (peer.executor() == executor() && !peer.writeInProgress) {
             finishPeerRead0(peer);
         } else {
             runFinishPeerReadTask(peer);
@@ -344,9 +344,9 @@ public class LocalChannel extends AbstractChannel {
         final Runnable finishPeerReadTask = () -> finishPeerRead0(peer);
         try {
             if (peer.writeInProgress) {
-                peer.finishReadFuture = peer.eventLoop().submit(finishPeerReadTask);
+                peer.finishReadFuture = peer.executor().submit(finishPeerReadTask);
             } else {
-                peer.eventLoop().execute(finishPeerReadTask);
+                peer.executor().execute(finishPeerReadTask);
             }
         } catch (Throwable cause) {
             logger.warn("Closing Local channels {}-{} because exception occurred!", this, peer, cause);
@@ -357,7 +357,7 @@ public class LocalChannel extends AbstractChannel {
     }
 
     private void releaseInboundBuffers() {
-        assert eventLoop() == null || eventLoop().inEventLoop();
+        assert executor() == null || executor().inEventLoop();
         readInProgress = false;
         Queue<Object> inboundBuffer = this.inboundBuffer;
         Object msg;
@@ -456,7 +456,7 @@ public class LocalChannel extends AbstractChannel {
                 // This ensures that if both channels are on the same event loop, the peer's channelActive
                 // event is triggered *after* this channel's channelRegistered event, so that this channel's
                 // pipeline is fully initialized by ChannelInitializer before any channelRead events.
-                peer.eventLoop().execute(() -> {
+                peer.executor().execute(() -> {
                     Promise<Void> promise = peer.connectPromise;
 
                     // Only trigger fireChannelActive() if the promise was not null and was not completed yet.

transport/src/main/java/io/netty/channel/local/LocalServerChannel.java

@@ -112,10 +112,10 @@ public class LocalServerChannel extends AbstractServerChannel {
 
     LocalChannel serve(final LocalChannel peer) {
         final LocalChannel child = newLocalChannel(peer);
-        if (eventLoop().inEventLoop()) {
+        if (executor().inEventLoop()) {
             serve0(child);
         } else {
-            eventLoop().execute(() -> serve0(child));
+            executor().execute(() -> serve0(child));
         }
         return child;
     }

transport/src/main/java/io/netty/channel/nio/AbstractNioByteChannel.java

@@ -302,7 +302,7 @@ public abstract class AbstractNioByteChannel extends AbstractNioChannel {
             clearOpWrite();
 
             // Schedule flush again later so other tasks can be picked up in the meantime
-            eventLoop().execute(flushTask);
+            executor().execute(flushTask);
         }
     }
 

transport/src/main/java/io/netty/channel/nio/AbstractNioChannel.java

@@ -125,7 +125,7 @@ public abstract class AbstractNioChannel extends AbstractChannel {
     @Deprecated
     protected void setReadPending(final boolean readPending) {
         if (isRegistered()) {
-            EventLoop eventLoop = eventLoop();
+            EventLoop eventLoop = executor();
             if (eventLoop.inEventLoop()) {
                 setReadPending0(readPending);
             } else {
@@ -144,7 +144,7 @@ public abstract class AbstractNioChannel extends AbstractChannel {
      */
     protected final void clearReadPending() {
         if (isRegistered()) {
-            EventLoop eventLoop = eventLoop();
+            EventLoop eventLoop = executor();
             if (eventLoop.inEventLoop()) {
                 clearReadPending0();
             } else {
@@ -237,7 +237,7 @@ public abstract class AbstractNioChannel extends AbstractChannel {
                     // Schedule connect timeout.
                     int connectTimeoutMillis = config().getConnectTimeoutMillis();
                     if (connectTimeoutMillis > 0) {
-                        connectTimeoutFuture = eventLoop().schedule(() -> {
+                        connectTimeoutFuture = executor().schedule(() -> {
                             Promise<Void> connectPromise = AbstractNioChannel.this.connectPromise;
                             if (connectPromise != null && !connectPromise.isDone()
                                     && connectPromise.tryFailure(new ConnectTimeoutException(
@@ -305,7 +305,7 @@ public abstract class AbstractNioChannel extends AbstractChannel {
             // Note this method is invoked by the event loop only if the connection attempt was
             // neither cancelled nor timed out.
 
-            assert eventLoop().inEventLoop();
+            assert executor().inEventLoop();
 
             try {
                 boolean wasActive = isActive();
@@ -348,12 +348,12 @@ public abstract class AbstractNioChannel extends AbstractChannel {
 
     @Override
     protected void doRegister() throws Exception {
-       eventLoop().unsafe().register(this);
+       executor().unsafe().register(this);
     }
 
     @Override
     protected void doDeregister() throws Exception {
-        eventLoop().unsafe().deregister(this);
+        executor().unsafe().deregister(this);
     }
 
     @Override

transport/src/main/java/io/netty/channel/nio/AbstractNioMessageChannel.java

@@ -66,7 +66,7 @@ public abstract class AbstractNioMessageChannel extends AbstractNioChannel {
 
         @Override
         public void read() {
-            assert eventLoop().inEventLoop();
+            assert executor().inEventLoop();
             final ChannelConfig config = config();
             final ChannelPipeline pipeline = pipeline();
             final RecvByteBufAllocator.Handle allocHandle = unsafe().recvBufAllocHandle();

transport/src/main/java/io/netty/channel/socket/nio/NioSocketChannel.java

@@ -164,7 +164,7 @@ public class NioSocketChannel extends AbstractNioByteChannel implements io.netty
 
     @Override
     public Future<Void> shutdownOutput(final Promise<Void> promise) {
-        final EventLoop loop = eventLoop();
+        final EventLoop loop = executor();
         if (loop.inEventLoop()) {
             ((AbstractUnsafe) unsafe()).shutdownOutput(promise);
         } else {
@@ -185,7 +185,7 @@ public class NioSocketChannel extends AbstractNioByteChannel implements io.netty
 
     @Override
     public Future<Void> shutdownInput(final Promise<Void> promise) {
-        EventLoop loop = eventLoop();
+        EventLoop loop = executor();
         if (loop.inEventLoop()) {
             shutdownInput0(promise);
         } else {

transport/src/test/java/io/netty/bootstrap/BootstrapTest.java

@@ -199,7 +199,7 @@ public class BootstrapTest {
             registerHandler.registerPromise().setSuccess(null);
             final BlockingQueue<Boolean> queue = new LinkedBlockingQueue<>();
             future.addListener(fut -> {
-                queue.add(fut.getNow().eventLoop().inEventLoop(Thread.currentThread()));
+                queue.add(fut.getNow().executor().inEventLoop(Thread.currentThread()));
                 queue.add(fut.isSuccess());
             });
             assertTrue(queue.take());

transport/src/test/java/io/netty/channel/ChannelInitializerTest.java

@@ -134,7 +134,7 @@ public class ChannelInitializerTest {
         try {
             // Execute some task on the EventLoop and wait until its done to be sure all handlers are added to the
             // pipeline.
-            channel.eventLoop().submit(() -> {
+            channel.executor().submit(() -> {
                 // NOOP
             }).syncUninterruptibly();
             Iterator<Map.Entry<String, ChannelHandler>> handlers = channel.pipeline().iterator();
@@ -171,7 +171,7 @@ public class ChannelInitializerTest {
         try {
             // Execute some task on the EventLoop and wait until its done to be sure all handlers are added to the
             // pipeline.
-            channel.eventLoop().submit(() -> {
+            channel.executor().submit(() -> {
                 // NOOP
             }).syncUninterruptibly();
             assertEquals(1, initChannelCalled.get());

transport/src/test/java/io/netty/channel/ChannelOutboundBufferTest.java

@@ -392,7 +392,7 @@ public class ChannelOutboundBufferTest {
 
         ChannelOutboundBuffer cob = ch.unsafe().outboundBuffer();
 
-        ch.eventLoop().execute(() -> {
+        ch.executor().execute(() -> {
             // Trigger channelWritabilityChanged() by writing a lot.
             ch.write(buffer().writeZero(257));
             assertThat(buf.toString(), is("false "));

transport/src/test/java/io/netty/channel/DefaultChannelPipelineTest.java

@@ -539,7 +539,7 @@ public class DefaultChannelPipelineTest {
 
             // Add handler.
             p.addFirst(handler.name, handler);
-            self.eventLoop().execute(() -> {
+            self.executor().execute(() -> {
                 // Validate handler life-cycle methods called.
                 handler.validate(true, false);
 
@@ -559,7 +559,7 @@ public class DefaultChannelPipelineTest {
         for (final LifeCycleAwareTestHandler handler : handlers) {
             assertSame(handler, p.remove(handler.name));
 
-            self.eventLoop().execute(() -> {
+            self.executor().execute(() -> {
                 // Validate handler life-cycle methods called.
                 handler.validate(true, true);
                 removeLatch.countDown();
@@ -576,7 +576,7 @@ public class DefaultChannelPipelineTest {
 
         setUp(handler1, handler2);
 
-        self.eventLoop().submit(() -> {
+        self.executor().submit(() -> {
             ChannelPipeline p = self.pipeline();
             handler1.inboundBuffer.add(8);
             assertEquals(8, handler1.inboundBuffer.peek());
@@ -595,7 +595,7 @@ public class DefaultChannelPipelineTest {
 
         setUp(handler1, handler2);
 
-        self.eventLoop().submit(() -> {
+        self.executor().submit(() -> {
             ChannelPipeline p = self.pipeline();
             handler2.outboundBuffer.add(8);
             assertEquals(8, handler2.outboundBuffer.peek());
@@ -614,7 +614,7 @@ public class DefaultChannelPipelineTest {
 
         setUp(handler1);
 
-        self.eventLoop().submit(() -> {
+        self.executor().submit(() -> {
             ChannelPipeline p = self.pipeline();
             handler1.outboundBuffer.add(8);
             assertEquals(8, handler1.outboundBuffer.peek());
@@ -632,7 +632,7 @@ public class DefaultChannelPipelineTest {
 
         setUp(handler1);
 
-        self.eventLoop().submit(() -> {
+        self.executor().submit(() -> {
             ChannelPipeline p = self.pipeline();
             handler1.inboundBuffer.add(8);
             handler1.outboundBuffer.add(8);
@@ -657,7 +657,7 @@ public class DefaultChannelPipelineTest {
 
         setUp(handler1, handler2, handler3);
 
-        self.eventLoop().submit(() -> {
+        self.executor().submit(() -> {
             ChannelPipeline p = self.pipeline();
             handler2.inboundBuffer.add(8);
             handler2.outboundBuffer.add(8);
@@ -1099,7 +1099,7 @@ public class DefaultChannelPipelineTest {
                 pipeline.channel().closeFuture().syncUninterruptibly();
 
                 // Schedule something on the EventLoop to ensure all other scheduled tasks had a chance to complete.
-                pipeline.channel().eventLoop().submit(() -> {
+                pipeline.channel().executor().submit(() -> {
                     // NOOP
                 }).syncUninterruptibly();
                 Error error = errorRef.get();
@@ -1543,7 +1543,7 @@ public class DefaultChannelPipelineTest {
         };
 
         if (executeInEventLoop) {
-            pipeline.channel().eventLoop().execute(r);
+            pipeline.channel().executor().execute(r);
         } else {
             r.run();
         }

transport/src/test/java/io/netty/channel/PendingWriteQueueTest.java

@@ -132,7 +132,7 @@ public class PendingWriteQueueTest {
 
         final PendingWriteQueue queue = queueRef.get();
 
-        channel.eventLoop().execute(() -> {
+        channel.executor().execute(() -> {
             // Trigger channelWritabilityChanged() by adding a message that's larger than the high watermark.
             queue.add(msg, channel.newPromise());
         });
@@ -212,7 +212,7 @@ public class PendingWriteQueueTest {
         promise.addListener(future -> queue.removeAndFailAll(new IllegalStateException()));
         Promise<Void> promise2 = channel.newPromise();
 
-        channel.eventLoop().execute(() -> {
+        channel.executor().execute(() -> {
             queue.add(1L, promise);
             queue.add(2L, promise2);
             queue.removeAndFailAll(new Exception());
@@ -244,7 +244,7 @@ public class PendingWriteQueueTest {
         });
         Promise<Void> promise2 = channel.newPromise();
 
-        channel.eventLoop().execute(() -> {
+        channel.executor().execute(() -> {
             queue.add(1L, promise);
             queue.add(2L, promise2);
             queue.removeAndWriteAll();
@@ -257,7 +257,7 @@ public class PendingWriteQueueTest {
         assertFalse(promise3.isDone());
         assertFalse(promise3.isSuccess());
 
-        channel.eventLoop().execute(queue::removeAndWriteAll);
+        channel.executor().execute(queue::removeAndWriteAll);
         assertTrue(promise3.isDone());
         assertTrue(promise3.isSuccess());
         channel.runPendingTasks();
@@ -284,7 +284,7 @@ public class PendingWriteQueueTest {
         });
         Promise<Void> promise2 = channel.newPromise();
         promise2.addListener(future -> failOrder.add(2));
-        channel.eventLoop().execute(() -> {
+        channel.executor().execute(() -> {
             queue.add(1L, promise);
             queue.add(2L, promise2);
             queue.removeAndFailAll(new Exception());
@@ -311,7 +311,7 @@ public class PendingWriteQueueTest {
         promise.addListener(future -> queue.removeAndWriteAll());
         Promise<Void> promise2 = channel.newPromise();
 
-        channel.eventLoop().execute(() -> {
+        channel.executor().execute(() -> {
             queue.add(1L, promise);
 
             queue.add(2L, promise2);
@@ -340,7 +340,7 @@ public class PendingWriteQueueTest {
 
         IllegalStateException ex = new IllegalStateException();
         Promise<Void> promise = channel.newPromise();
-        channel.eventLoop().execute(() -> {
+        channel.executor().execute(() -> {
             queue.add(1L, promise);
             queue.removeAndFailAll(ex);
         });

transport/src/test/java/io/netty/channel/embedded/EmbeddedChannelTest.java

@@ -125,7 +125,7 @@ public class EmbeddedChannelTest {
     public void testScheduling() throws Exception {
         EmbeddedChannel ch = new EmbeddedChannel(new ChannelHandler() { });
         final CountDownLatch latch = new CountDownLatch(2);
-        ScheduledFuture future = ch.eventLoop().schedule(latch::countDown, 1, TimeUnit.SECONDS);
+        ScheduledFuture future = ch.executor().schedule(latch::countDown, 1, TimeUnit.SECONDS);
         future.addListener(future1 -> latch.countDown());
         long next = ch.runScheduledPendingTasks();
         assertTrue(next > 0);
@@ -139,7 +139,7 @@ public class EmbeddedChannelTest {
     @Test
     public void testScheduledCancelled() throws Exception {
         EmbeddedChannel ch = new EmbeddedChannel(new ChannelHandler() { });
-        ScheduledFuture<?> future = ch.eventLoop().schedule(() -> { }, 1, TimeUnit.DAYS);
+        ScheduledFuture<?> future = ch.executor().schedule(() -> { }, 1, TimeUnit.DAYS);
         ch.finish();
         assertTrue(future.isCancelled());
     }

transport/src/test/java/io/netty/channel/local/LocalChannelTest.java

@@ -119,7 +119,7 @@ public class LocalChannelTest {
                 // Connect to the server
                 cc = cb.connect(sc.localAddress()).get();
                 final Channel ccCpy = cc;
-                cc.eventLoop().execute(() -> {
+                cc.executor().execute(() -> {
                     // Send a message event up the pipeline.
                     ccCpy.pipeline().fireChannelRead("Hello, World");
                     latch.countDown();
@@ -715,7 +715,7 @@ public class LocalChannelTest {
                 cc.pipeline().lastContext().executor().execute(() ->
                         ccCpy.writeAndFlush(data.retainedDuplicate())
                 .addListener(future -> {
-                    serverChannelCpy.eventLoop().execute(() -> {
+                    serverChannelCpy.executor().execute(() -> {
                         // The point of this test is to write while the peer is closed, so we should
                         // ensure the peer is actually closed before we write.
                         int waitCount = 0;
@@ -784,7 +784,7 @@ public class LocalChannelTest {
             cc = cb.register().get();
 
             final AtomicReference<Future<Void>> ref = new AtomicReference<>();
-            final Promise<Void> assertPromise = cc.eventLoop().newPromise();
+            final Promise<Void> assertPromise = cc.executor().newPromise();
 
             cc.pipeline().addLast(new TestHandler() {
                 @Override

transport/src/test/java/io/netty/channel/local/LocalTransportThreadModelTest2.java

@@ -76,7 +76,7 @@ public class LocalTransportThreadModelTest2 {
 
     public void close(final Channel localChannel, final LocalHandler localRegistrationHandler) {
         // we want to make sure we actually shutdown IN the event loop
-        if (localChannel.eventLoop().inEventLoop()) {
+        if (localChannel.executor().inEventLoop()) {
             // Wait until all messages are flushed before closing the channel.
             if (localRegistrationHandler.lastWriteFuture != null) {
                 localRegistrationHandler.lastWriteFuture.awaitUninterruptibly();
@@ -86,7 +86,7 @@ public class LocalTransportThreadModelTest2 {
             return;
         }
 
-        localChannel.eventLoop().execute(() -> close(localChannel, localRegistrationHandler));
+        localChannel.executor().execute(() -> close(localChannel, localRegistrationHandler));
 
         // Wait until the connection is closed or the connection attempt fails.
         localChannel.closeFuture().awaitUninterruptibly();

transport/src/test/java/io/netty/channel/socket/nio/AbstractNioChannelTest.java

@@ -190,7 +190,7 @@ public abstract class AbstractNioChannelTest<T extends AbstractNioChannel> {
         T channel = newNioChannel(wrapped);
         channel.register().syncUninterruptibly();
 
-        assertSame(wrapped, channel.eventLoop());
+        assertSame(wrapped, channel.executor());
         channel.close().syncUninterruptibly();
         eventLoopGroup.shutdownGracefully();
     }