diff --git a/codec-http/src/test/java/io/netty/handler/codec/http/HttpClientCodecTest.java b/codec-http/src/test/java/io/netty/handler/codec/http/HttpClientCodecTest.java
index d2faab828e6..5650a614588 100644
--- a/codec-http/src/test/java/io/netty/handler/codec/http/HttpClientCodecTest.java
+++ b/codec-http/src/test/java/io/netty/handler/codec/http/HttpClientCodecTest.java
@@ -25,9 +25,10 @@
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.ChannelInitializer;
 import io.netty.channel.ChannelOption;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
 import io.netty.channel.SimpleChannelInboundHandler;
 import io.netty.channel.embedded.EmbeddedChannel;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.SocketChannel;
 import io.netty.channel.socket.nio.NioServerSocketChannel;
 import io.netty.channel.socket.nio.NioSocketChannel;
@@ -129,7 +130,7 @@ public void testServerCloseSocketInputProvidesData() throws InterruptedException
         final CountDownLatch serverChannelLatch = new CountDownLatch(1);
         final CountDownLatch responseReceivedLatch = new CountDownLatch(1);
         try {
-            sb.group(new NioEventLoopGroup(2));
+            sb.group(new MultiThreadIoEventLoopGroup(2, NioIoHandler.newFactory()));
             sb.channel(NioServerSocketChannel.class);
             sb.childHandler(new ChannelInitializer<Channel>() {
                 @Override
@@ -173,7 +174,7 @@ public void operationComplete(ChannelFuture future) throws Exception {
                 }
             });
 
-            cb.group(new NioEventLoopGroup(1));
+            cb.group(new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory()));
             cb.channel(NioSocketChannel.class);
             cb.option(ChannelOption.ALLOW_HALF_CLOSURE, true);
             cb.handler(new ChannelInitializer<Channel>() {
diff --git a/codec-http2/src/test/java/io/netty/handler/codec/http2/DataCompressionHttp2Test.java b/codec-http2/src/test/java/io/netty/handler/codec/http2/DataCompressionHttp2Test.java
index 04014497b62..283b655baad 100644
--- a/codec-http2/src/test/java/io/netty/handler/codec/http2/DataCompressionHttp2Test.java
+++ b/codec-http2/src/test/java/io/netty/handler/codec/http2/DataCompressionHttp2Test.java
@@ -25,7 +25,8 @@
 import io.netty.channel.ChannelInitializer;
 import io.netty.channel.ChannelPipeline;
 import io.netty.channel.ChannelPromise;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.nio.NioServerSocketChannel;
 import io.netty.channel.socket.nio.NioSocketChannel;
 import io.netty.handler.codec.compression.Brotli;
@@ -449,7 +450,8 @@ public Integer answer(InvocationOnMock in) throws Throwable {
                 any(ByteBuf.class), anyInt(), anyBoolean());
 
         final CountDownLatch serverChannelLatch = new CountDownLatch(1);
-        sb.group(new NioEventLoopGroup(), new NioEventLoopGroup());
+        sb.group(new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory()),
+                new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory()));
         sb.channel(NioServerSocketChannel.class);
         sb.childHandler(new ChannelInitializer<Channel>() {
             @Override
@@ -473,7 +475,7 @@ protected void initChannel(Channel ch) throws Exception {
             }
         });
 
-        cb.group(new NioEventLoopGroup());
+        cb.group(new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory()));
         cb.channel(NioSocketChannel.class);
         cb.handler(new ChannelInitializer<Channel>() {
             @Override
diff --git a/codec-http2/src/test/java/io/netty/handler/codec/http2/DefaultHttp2ConnectionTest.java b/codec-http2/src/test/java/io/netty/handler/codec/http2/DefaultHttp2ConnectionTest.java
index 1574d16828d..65457c17ff7 100644
--- a/codec-http2/src/test/java/io/netty/handler/codec/http2/DefaultHttp2ConnectionTest.java
+++ b/codec-http2/src/test/java/io/netty/handler/codec/http2/DefaultHttp2ConnectionTest.java
@@ -17,7 +17,9 @@
 
 import io.netty.buffer.ByteBuf;
 import io.netty.buffer.Unpooled;
-import io.netty.channel.DefaultEventLoopGroup;
+import io.netty.channel.EventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.local.LocalIoHandler;
 import io.netty.handler.codec.http2.Http2Connection.Endpoint;
 import io.netty.handler.codec.http2.Http2Stream.State;
 import io.netty.util.concurrent.Future;
@@ -59,7 +61,7 @@ public class DefaultHttp2ConnectionTest {
 
     private DefaultHttp2Connection server;
     private DefaultHttp2Connection client;
-    private static DefaultEventLoopGroup group;
+    private static EventLoopGroup group;
 
     @Mock
     private Http2Connection.Listener clientListener;
@@ -69,7 +71,7 @@ public class DefaultHttp2ConnectionTest {
 
     @BeforeAll
     public static void beforeClass() {
-        group = new DefaultEventLoopGroup(2);
+        group = new MultiThreadIoEventLoopGroup(2, LocalIoHandler.newFactory());
     }
 
     @AfterAll
diff --git a/codec-http2/src/test/java/io/netty/handler/codec/http2/DefaultHttp2PushPromiseFrameTest.java b/codec-http2/src/test/java/io/netty/handler/codec/http2/DefaultHttp2PushPromiseFrameTest.java
index 04acf60d55f..8cae6ec8667 100644
--- a/codec-http2/src/test/java/io/netty/handler/codec/http2/DefaultHttp2PushPromiseFrameTest.java
+++ b/codec-http2/src/test/java/io/netty/handler/codec/http2/DefaultHttp2PushPromiseFrameTest.java
@@ -24,7 +24,8 @@
 import io.netty.channel.ChannelInitializer;
 import io.netty.channel.ChannelPipeline;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.SocketChannel;
 import io.netty.channel.socket.nio.NioServerSocketChannel;
 import io.netty.channel.socket.nio.NioSocketChannel;
@@ -42,7 +43,7 @@
 
 public class DefaultHttp2PushPromiseFrameTest {
 
-    private final EventLoopGroup eventLoopGroup = new NioEventLoopGroup(2);
+    private final EventLoopGroup eventLoopGroup = new MultiThreadIoEventLoopGroup(2, NioIoHandler.newFactory());
     private final ClientHandler clientHandler = new ClientHandler();
     private final Map<Integer, String> contentMap = new ConcurrentHashMap<Integer, String>();
 
diff --git a/codec-http2/src/test/java/io/netty/handler/codec/http2/Http2MultiplexTransportTest.java b/codec-http2/src/test/java/io/netty/handler/codec/http2/Http2MultiplexTransportTest.java
index c3709102b06..848a15fc791 100644
--- a/codec-http2/src/test/java/io/netty/handler/codec/http2/Http2MultiplexTransportTest.java
+++ b/codec-http2/src/test/java/io/netty/handler/codec/http2/Http2MultiplexTransportTest.java
@@ -30,11 +30,12 @@
 import io.netty.channel.ChannelPipeline;
 import io.netty.channel.DefaultEventLoop;
 import io.netty.channel.EventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
 import io.netty.channel.SimpleChannelInboundHandler;
 import io.netty.channel.local.LocalAddress;
 import io.netty.channel.local.LocalChannel;
 import io.netty.channel.local.LocalServerChannel;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.nio.NioServerSocketChannel;
 import io.netty.channel.socket.nio.NioSocketChannel;
 import io.netty.handler.codec.http.DefaultFullHttpRequest;
@@ -163,7 +164,7 @@ private static String generateLargeString(int sizeInBytes) {
 
     @BeforeEach
     public void setup() {
-        eventLoopGroup = new NioEventLoopGroup();
+        eventLoopGroup = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
     }
 
     @AfterEach
@@ -668,19 +669,19 @@ public void streamHandlerInactivatedResponseFlushed() throws InterruptedExceptio
         EventLoopGroup clientEventLoopGroup = null;
 
         try {
-            serverEventLoopGroup = new NioEventLoopGroup(1, new ThreadFactory() {
+            serverEventLoopGroup = new MultiThreadIoEventLoopGroup(1, new ThreadFactory() {
                 @Override
                 public Thread newThread(Runnable r) {
                     return new Thread(r, "serverloop");
                 }
-            });
+            }, NioIoHandler.newFactory());
 
-            clientEventLoopGroup = new NioEventLoopGroup(1, new ThreadFactory() {
+            clientEventLoopGroup = new MultiThreadIoEventLoopGroup(1, new ThreadFactory() {
                 @Override
                 public Thread newThread(Runnable r) {
                     return new Thread(r, "clientloop");
                 }
-            });
+            }, NioIoHandler.newFactory());
 
             final int streams = 10;
             final CountDownLatch latchClientResponses = new CountDownLatch(streams);
diff --git a/codec/src/test/java/io/netty/handler/codec/compression/Lz4FrameEncoderTest.java b/codec/src/test/java/io/netty/handler/codec/compression/Lz4FrameEncoderTest.java
index 483e75297e4..6ce490feadb 100644
--- a/codec/src/test/java/io/netty/handler/codec/compression/Lz4FrameEncoderTest.java
+++ b/codec/src/test/java/io/netty/handler/codec/compression/Lz4FrameEncoderTest.java
@@ -27,8 +27,9 @@
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.ChannelInitializer;
 import io.netty.channel.EventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
 import io.netty.channel.embedded.EmbeddedChannel;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.nio.NioServerSocketChannel;
 import io.netty.channel.socket.nio.NioSocketChannel;
 import io.netty.handler.codec.EncoderException;
@@ -255,7 +256,7 @@ public void testAllocatingAroundBlockSize() {
     @Test
     @Timeout(value = 3000, unit = TimeUnit.MILLISECONDS)
     public void writingAfterClosedChannelDoesNotNPE() throws InterruptedException {
-        EventLoopGroup group = new NioEventLoopGroup(2);
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(2, NioIoHandler.newFactory());
         Channel serverChannel = null;
         Channel clientChannel = null;
         final CountDownLatch latch = new CountDownLatch(1);
diff --git a/example/src/main/java/io/netty/example/discard/DiscardClient.java b/example/src/main/java/io/netty/example/discard/DiscardClient.java
index 32562f89ae5..cdfb37cdc98 100644
--- a/example/src/main/java/io/netty/example/discard/DiscardClient.java
+++ b/example/src/main/java/io/netty/example/discard/DiscardClient.java
@@ -20,7 +20,8 @@
 import io.netty.channel.ChannelInitializer;
 import io.netty.channel.ChannelPipeline;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.SocketChannel;
 import io.netty.channel.socket.nio.NioSocketChannel;
 import io.netty.example.util.ServerUtil;
@@ -39,7 +40,7 @@ public static void main(String[] args) throws Exception {
         // Configure SSL.
         final SslContext sslCtx = ServerUtil.buildSslContext();
 
-        EventLoopGroup group = new NioEventLoopGroup();
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         try {
             Bootstrap b = new Bootstrap();
             b.group(group)
diff --git a/example/src/main/java/io/netty/example/discard/DiscardServer.java b/example/src/main/java/io/netty/example/discard/DiscardServer.java
index 33c7ff19920..1607235b1c5 100644
--- a/example/src/main/java/io/netty/example/discard/DiscardServer.java
+++ b/example/src/main/java/io/netty/example/discard/DiscardServer.java
@@ -20,7 +20,8 @@
 import io.netty.channel.ChannelInitializer;
 import io.netty.channel.ChannelPipeline;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.SocketChannel;
 import io.netty.channel.socket.nio.NioServerSocketChannel;
 import io.netty.example.util.ServerUtil;
@@ -39,8 +40,8 @@ public static void main(String[] args) throws Exception {
         // Configure SSL.
         final SslContext sslCtx = ServerUtil.buildSslContext();
 
-        EventLoopGroup bossGroup = new NioEventLoopGroup(1);
-        EventLoopGroup workerGroup = new NioEventLoopGroup();
+        EventLoopGroup bossGroup = new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory());
+        EventLoopGroup workerGroup = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         try {
             ServerBootstrap b = new ServerBootstrap();
             b.group(bossGroup, workerGroup)
diff --git a/example/src/main/java/io/netty/example/dns/dot/DoTClient.java b/example/src/main/java/io/netty/example/dns/dot/DoTClient.java
index 7224d90d9c1..0a04e5996d9 100644
--- a/example/src/main/java/io/netty/example/dns/dot/DoTClient.java
+++ b/example/src/main/java/io/netty/example/dns/dot/DoTClient.java
@@ -23,7 +23,8 @@
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.ChannelPipeline;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.SocketChannel;
 import io.netty.channel.socket.nio.NioSocketChannel;
 import io.netty.channel.SimpleChannelInboundHandler;
@@ -71,7 +72,7 @@ private static void handleQueryResp(DefaultDnsResponse msg) {
     }
 
     public static void main(String[] args) throws Exception {
-        EventLoopGroup group = new NioEventLoopGroup();
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         try {
             final SslContext sslContext = SslContextBuilder.forClient()
                     .protocols("TLSv1.3", "TLSv1.2")
diff --git a/example/src/main/java/io/netty/example/dns/tcp/TcpDnsClient.java b/example/src/main/java/io/netty/example/dns/tcp/TcpDnsClient.java
index e91ca25059c..20510c1ef4e 100644
--- a/example/src/main/java/io/netty/example/dns/tcp/TcpDnsClient.java
+++ b/example/src/main/java/io/netty/example/dns/tcp/TcpDnsClient.java
@@ -23,7 +23,8 @@
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.ChannelPipeline;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.SocketChannel;
 import io.netty.channel.socket.nio.NioSocketChannel;
 import io.netty.channel.SimpleChannelInboundHandler;
@@ -69,7 +70,7 @@ private static void handleQueryResp(DefaultDnsResponse msg) {
     }
 
     public static void main(String[] args) throws Exception {
-        EventLoopGroup group = new NioEventLoopGroup();
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         try {
             Bootstrap b = new Bootstrap();
             b.group(group)
diff --git a/example/src/main/java/io/netty/example/dns/tcp/TcpDnsServer.java b/example/src/main/java/io/netty/example/dns/tcp/TcpDnsServer.java
index d72070b0ba6..a1b41a85582 100644
--- a/example/src/main/java/io/netty/example/dns/tcp/TcpDnsServer.java
+++ b/example/src/main/java/io/netty/example/dns/tcp/TcpDnsServer.java
@@ -22,8 +22,10 @@
 import io.netty.channel.Channel;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.ChannelInitializer;
+import io.netty.channel.EventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
 import io.netty.channel.SimpleChannelInboundHandler;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.SocketChannel;
 import io.netty.channel.socket.nio.NioServerSocketChannel;
 import io.netty.channel.socket.nio.NioSocketChannel;
@@ -57,8 +59,9 @@ public final class TcpDnsServer {
     private static final byte[] QUERY_RESULT = new byte[]{(byte) 192, (byte) 168, 1, 1};
 
     public static void main(String[] args) throws Exception {
-        ServerBootstrap bootstrap = new ServerBootstrap().group(new NioEventLoopGroup(1),
-                new NioEventLoopGroup())
+        ServerBootstrap bootstrap = new ServerBootstrap().group(
+                new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory()),
+                new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory()))
                 .channel(NioServerSocketChannel.class)
                 .handler(new LoggingHandler(LogLevel.INFO))
                 .childHandler(new ChannelInitializer<Channel>() {
@@ -110,7 +113,7 @@ public void run() {
 
     // copy from TcpDnsClient.java
     private static void clientQuery() throws Exception {
-        NioEventLoopGroup group = new NioEventLoopGroup();
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         try {
             Bootstrap b = new Bootstrap();
             b.group(group)
diff --git a/example/src/main/java/io/netty/example/dns/udp/DnsClient.java b/example/src/main/java/io/netty/example/dns/udp/DnsClient.java
index 396d9abdd6c..da869366236 100644
--- a/example/src/main/java/io/netty/example/dns/udp/DnsClient.java
+++ b/example/src/main/java/io/netty/example/dns/udp/DnsClient.java
@@ -25,8 +25,9 @@
 import io.netty.channel.ChannelInitializer;
 import io.netty.channel.ChannelPipeline;
 import io.netty.channel.EventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
 import io.netty.channel.SimpleChannelInboundHandler;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.DatagramChannel;
 import io.netty.channel.socket.nio.NioDatagramChannel;
 import io.netty.handler.codec.dns.DatagramDnsQuery;
@@ -67,7 +68,7 @@ private static void handleQueryResp(DatagramDnsResponse msg) {
 
     public static void main(String[] args) throws Exception {
         InetSocketAddress addr = new InetSocketAddress(DNS_SERVER_HOST, DNS_SERVER_PORT);
-        EventLoopGroup group = new NioEventLoopGroup();
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         try {
             Bootstrap b = new Bootstrap();
             b.group(group)
diff --git a/example/src/main/java/io/netty/example/echo/EchoClient.java b/example/src/main/java/io/netty/example/echo/EchoClient.java
index c7ccc484ad7..987649a0ce5 100644
--- a/example/src/main/java/io/netty/example/echo/EchoClient.java
+++ b/example/src/main/java/io/netty/example/echo/EchoClient.java
@@ -21,7 +21,8 @@
 import io.netty.channel.ChannelOption;
 import io.netty.channel.ChannelPipeline;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.SocketChannel;
 import io.netty.channel.socket.nio.NioSocketChannel;
 import io.netty.example.util.ServerUtil;
@@ -44,7 +45,7 @@ public static void main(String[] args) throws Exception {
         final SslContext sslCtx = ServerUtil.buildSslContext();
 
         // Configure the client.
-        EventLoopGroup group = new NioEventLoopGroup();
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         try {
             Bootstrap b = new Bootstrap();
             b.group(group)
diff --git a/example/src/main/java/io/netty/example/echo/EchoServer.java b/example/src/main/java/io/netty/example/echo/EchoServer.java
index 69625458be0..db113f96bf0 100644
--- a/example/src/main/java/io/netty/example/echo/EchoServer.java
+++ b/example/src/main/java/io/netty/example/echo/EchoServer.java
@@ -21,7 +21,8 @@
 import io.netty.channel.ChannelOption;
 import io.netty.channel.ChannelPipeline;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.SocketChannel;
 import io.netty.channel.socket.nio.NioServerSocketChannel;
 import io.netty.example.util.ServerUtil;
@@ -41,8 +42,8 @@ public static void main(String[] args) throws Exception {
         final SslContext sslCtx = ServerUtil.buildSslContext();
 
         // Configure the server.
-        EventLoopGroup bossGroup = new NioEventLoopGroup(1);
-        EventLoopGroup workerGroup = new NioEventLoopGroup();
+        EventLoopGroup bossGroup = new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory());
+        EventLoopGroup workerGroup = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         final EchoServerHandler serverHandler = new EchoServerHandler();
         try {
             ServerBootstrap b = new ServerBootstrap();
diff --git a/example/src/main/java/io/netty/example/factorial/FactorialClient.java b/example/src/main/java/io/netty/example/factorial/FactorialClient.java
index 85123d4fc51..e6cd9858d37 100644
--- a/example/src/main/java/io/netty/example/factorial/FactorialClient.java
+++ b/example/src/main/java/io/netty/example/factorial/FactorialClient.java
@@ -18,7 +18,8 @@
 import io.netty.bootstrap.Bootstrap;
 import io.netty.channel.ChannelFuture;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.nio.NioSocketChannel;
 import io.netty.example.util.ServerUtil;
 import io.netty.handler.ssl.SslContext;
@@ -37,7 +38,7 @@ public static void main(String[] args) throws Exception {
         // Configure SSL.
         final SslContext sslCtx = ServerUtil.buildSslContext();
 
-        EventLoopGroup group = new NioEventLoopGroup();
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         try {
             Bootstrap b = new Bootstrap();
             b.group(group)
diff --git a/example/src/main/java/io/netty/example/factorial/FactorialServer.java b/example/src/main/java/io/netty/example/factorial/FactorialServer.java
index 3ac93e53acf..877f77abc2c 100644
--- a/example/src/main/java/io/netty/example/factorial/FactorialServer.java
+++ b/example/src/main/java/io/netty/example/factorial/FactorialServer.java
@@ -17,7 +17,8 @@
 
 import io.netty.bootstrap.ServerBootstrap;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.nio.NioServerSocketChannel;
 import io.netty.example.util.ServerUtil;
 import io.netty.handler.logging.LogLevel;
@@ -36,8 +37,8 @@ public static void main(String[] args) throws Exception {
         // Configure SSL.
         final SslContext sslCtx = ServerUtil.buildSslContext();
 
-        EventLoopGroup bossGroup = new NioEventLoopGroup(1);
-        EventLoopGroup workerGroup = new NioEventLoopGroup();
+        EventLoopGroup bossGroup = new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory());
+        EventLoopGroup workerGroup = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         try {
             ServerBootstrap b = new ServerBootstrap();
             b.group(bossGroup, workerGroup)
diff --git a/example/src/main/java/io/netty/example/file/FileServer.java b/example/src/main/java/io/netty/example/file/FileServer.java
index 8b2eb7c319d..9969725a2cc 100644
--- a/example/src/main/java/io/netty/example/file/FileServer.java
+++ b/example/src/main/java/io/netty/example/file/FileServer.java
@@ -21,7 +21,8 @@
 import io.netty.channel.ChannelOption;
 import io.netty.channel.ChannelPipeline;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.SocketChannel;
 import io.netty.channel.socket.nio.NioServerSocketChannel;
 import io.netty.example.util.ServerUtil;
@@ -48,8 +49,8 @@ public static void main(String[] args) throws Exception {
         final SslContext sslCtx = ServerUtil.buildSslContext();
 
         // Configure the server.
-        EventLoopGroup bossGroup = new NioEventLoopGroup(1);
-        EventLoopGroup workerGroup = new NioEventLoopGroup();
+        EventLoopGroup bossGroup = new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory());
+        EventLoopGroup workerGroup = new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory());
         try {
             ServerBootstrap b = new ServerBootstrap();
             b.group(bossGroup, workerGroup)
diff --git a/example/src/main/java/io/netty/example/haproxy/HAProxyClient.java b/example/src/main/java/io/netty/example/haproxy/HAProxyClient.java
index fdd9e219b15..bd4efd42b4a 100644
--- a/example/src/main/java/io/netty/example/haproxy/HAProxyClient.java
+++ b/example/src/main/java/io/netty/example/haproxy/HAProxyClient.java
@@ -20,7 +20,8 @@
 import io.netty.buffer.Unpooled;
 import io.netty.channel.Channel;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.nio.NioSocketChannel;
 import io.netty.handler.codec.haproxy.HAProxyCommand;
 import io.netty.handler.codec.haproxy.HAProxyMessage;
@@ -35,7 +36,7 @@ public final class HAProxyClient {
     private static final String HOST = System.getProperty("host", "127.0.0.1");
 
     public static void main(String[] args) throws Exception {
-        EventLoopGroup group = new NioEventLoopGroup();
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         try {
             Bootstrap b = new Bootstrap();
             b.group(group)
diff --git a/example/src/main/java/io/netty/example/haproxy/HAProxyServer.java b/example/src/main/java/io/netty/example/haproxy/HAProxyServer.java
index dfb66f42d32..f9e4cede704 100644
--- a/example/src/main/java/io/netty/example/haproxy/HAProxyServer.java
+++ b/example/src/main/java/io/netty/example/haproxy/HAProxyServer.java
@@ -22,8 +22,9 @@
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.ChannelInitializer;
 import io.netty.channel.EventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
 import io.netty.channel.SimpleChannelInboundHandler;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.SocketChannel;
 import io.netty.channel.socket.nio.NioServerSocketChannel;
 import io.netty.handler.codec.haproxy.HAProxyMessage;
@@ -36,8 +37,8 @@ public final class HAProxyServer {
     static final int PORT = Integer.parseInt(System.getProperty("port", "8080"));
 
     public static void main(String[] args) throws Exception {
-        EventLoopGroup bossGroup = new NioEventLoopGroup(1);
-        EventLoopGroup workerGroup = new NioEventLoopGroup();
+        EventLoopGroup bossGroup = new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory());
+        EventLoopGroup workerGroup = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         try {
             ServerBootstrap b = new ServerBootstrap();
             b.group(bossGroup, workerGroup)
diff --git a/example/src/main/java/io/netty/example/http/cors/HttpCorsServer.java b/example/src/main/java/io/netty/example/http/cors/HttpCorsServer.java
index f9908ea2a99..e1c83535a1c 100644
--- a/example/src/main/java/io/netty/example/http/cors/HttpCorsServer.java
+++ b/example/src/main/java/io/netty/example/http/cors/HttpCorsServer.java
@@ -17,7 +17,8 @@
 
 import io.netty.bootstrap.ServerBootstrap;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.nio.NioServerSocketChannel;
 import io.netty.example.util.ServerUtil;
 import io.netty.handler.logging.LogLevel;
@@ -79,8 +80,8 @@ public static void main(String[] args) throws Exception {
         // Configure SSL.
         final SslContext sslCtx = ServerUtil.buildSslContext();
 
-        EventLoopGroup bossGroup = new NioEventLoopGroup(1);
-        EventLoopGroup workerGroup = new NioEventLoopGroup();
+        EventLoopGroup bossGroup = new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory());
+        EventLoopGroup workerGroup = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         try {
             ServerBootstrap b = new ServerBootstrap();
             b.group(bossGroup, workerGroup)
diff --git a/example/src/main/java/io/netty/example/http/file/HttpStaticFileServer.java b/example/src/main/java/io/netty/example/http/file/HttpStaticFileServer.java
index adeca2ada59..dbec3dae149 100644
--- a/example/src/main/java/io/netty/example/http/file/HttpStaticFileServer.java
+++ b/example/src/main/java/io/netty/example/http/file/HttpStaticFileServer.java
@@ -18,7 +18,8 @@
 import io.netty.bootstrap.ServerBootstrap;
 import io.netty.channel.Channel;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.nio.NioServerSocketChannel;
 import io.netty.example.util.ServerUtil;
 import io.netty.handler.logging.LogLevel;
@@ -34,8 +35,8 @@ public static void main(String[] args) throws Exception {
         // Configure SSL.
         final SslContext sslCtx = ServerUtil.buildSslContext();
 
-        EventLoopGroup bossGroup = new NioEventLoopGroup(1);
-        EventLoopGroup workerGroup = new NioEventLoopGroup();
+        EventLoopGroup bossGroup = new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory());
+        EventLoopGroup workerGroup = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         try {
             ServerBootstrap b = new ServerBootstrap();
             b.group(bossGroup, workerGroup)
diff --git a/example/src/main/java/io/netty/example/http/helloworld/HttpHelloWorldServer.java b/example/src/main/java/io/netty/example/http/helloworld/HttpHelloWorldServer.java
index 23ce5a747d7..ab6708b5caf 100644
--- a/example/src/main/java/io/netty/example/http/helloworld/HttpHelloWorldServer.java
+++ b/example/src/main/java/io/netty/example/http/helloworld/HttpHelloWorldServer.java
@@ -19,7 +19,8 @@
 import io.netty.channel.Channel;
 import io.netty.channel.ChannelOption;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.nio.NioServerSocketChannel;
 import io.netty.example.util.ServerUtil;
 import io.netty.handler.logging.LogLevel;
@@ -40,8 +41,8 @@ public static void main(String[] args) throws Exception {
         final SslContext sslCtx = ServerUtil.buildSslContext();
 
         // Configure the server.
-        EventLoopGroup bossGroup = new NioEventLoopGroup(1);
-        EventLoopGroup workerGroup = new NioEventLoopGroup();
+        EventLoopGroup bossGroup = new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory());
+        EventLoopGroup workerGroup = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         try {
             ServerBootstrap b = new ServerBootstrap();
             b.option(ChannelOption.SO_BACKLOG, 1024);
diff --git a/example/src/main/java/io/netty/example/http/snoop/HttpSnoopClient.java b/example/src/main/java/io/netty/example/http/snoop/HttpSnoopClient.java
index 32aef98c171..7c56850ff73 100644
--- a/example/src/main/java/io/netty/example/http/snoop/HttpSnoopClient.java
+++ b/example/src/main/java/io/netty/example/http/snoop/HttpSnoopClient.java
@@ -19,7 +19,8 @@
 import io.netty.buffer.Unpooled;
 import io.netty.channel.Channel;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.nio.NioSocketChannel;
 import io.netty.handler.codec.http.DefaultFullHttpRequest;
 import io.netty.handler.codec.http.HttpHeaderNames;
@@ -72,7 +73,7 @@ public static void main(String[] args) throws Exception {
         }
 
         // Configure the client.
-        EventLoopGroup group = new NioEventLoopGroup();
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         try {
             Bootstrap b = new Bootstrap();
             b.group(group)
diff --git a/example/src/main/java/io/netty/example/http/snoop/HttpSnoopServer.java b/example/src/main/java/io/netty/example/http/snoop/HttpSnoopServer.java
index b6f6a239724..e7ed3f1e170 100644
--- a/example/src/main/java/io/netty/example/http/snoop/HttpSnoopServer.java
+++ b/example/src/main/java/io/netty/example/http/snoop/HttpSnoopServer.java
@@ -18,7 +18,8 @@
 import io.netty.bootstrap.ServerBootstrap;
 import io.netty.channel.Channel;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.nio.NioServerSocketChannel;
 import io.netty.example.util.ServerUtil;
 import io.netty.handler.logging.LogLevel;
@@ -39,8 +40,8 @@ public static void main(String[] args) throws Exception {
         final SslContext sslCtx = ServerUtil.buildSslContext();
 
         // Configure the server.
-        EventLoopGroup bossGroup = new NioEventLoopGroup(1);
-        EventLoopGroup workerGroup = new NioEventLoopGroup();
+        EventLoopGroup bossGroup = new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory());
+        EventLoopGroup workerGroup = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         try {
             ServerBootstrap b = new ServerBootstrap();
             b.group(bossGroup, workerGroup)
diff --git a/example/src/main/java/io/netty/example/http/upload/HttpUploadClient.java b/example/src/main/java/io/netty/example/http/upload/HttpUploadClient.java
index 712d4c646ba..0cd9411ea8a 100644
--- a/example/src/main/java/io/netty/example/http/upload/HttpUploadClient.java
+++ b/example/src/main/java/io/netty/example/http/upload/HttpUploadClient.java
@@ -19,7 +19,8 @@
 import io.netty.channel.Channel;
 import io.netty.channel.ChannelFuture;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.nio.NioSocketChannel;
 import io.netty.handler.codec.http.DefaultHttpRequest;
 import io.netty.handler.codec.http.LastHttpContent;
@@ -102,7 +103,7 @@ public static void main(String[] args) throws Exception {
         }
 
         // Configure the client.
-        EventLoopGroup group = new NioEventLoopGroup();
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
 
         // setup the factory: here using a mixed memory/disk based on size threshold
         HttpDataFactory factory = new DefaultHttpDataFactory(DefaultHttpDataFactory.MINSIZE); // Disk if MINSIZE exceed
diff --git a/example/src/main/java/io/netty/example/http/upload/HttpUploadServer.java b/example/src/main/java/io/netty/example/http/upload/HttpUploadServer.java
index 1c1abaa1e53..9570a8a7c16 100644
--- a/example/src/main/java/io/netty/example/http/upload/HttpUploadServer.java
+++ b/example/src/main/java/io/netty/example/http/upload/HttpUploadServer.java
@@ -18,7 +18,8 @@
 import io.netty.bootstrap.ServerBootstrap;
 import io.netty.channel.Channel;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.nio.NioServerSocketChannel;
 import io.netty.example.util.ServerUtil;
 import io.netty.handler.logging.LogLevel;
@@ -37,8 +38,8 @@ public static void main(String[] args) throws Exception {
         // Configure SSL.
         final SslContext sslCtx = ServerUtil.buildSslContext();
 
-        EventLoopGroup bossGroup = new NioEventLoopGroup(1);
-        EventLoopGroup workerGroup = new NioEventLoopGroup();
+        EventLoopGroup bossGroup = new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory());
+        EventLoopGroup workerGroup = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         try {
             ServerBootstrap b = new ServerBootstrap();
             b.group(bossGroup, workerGroup);
diff --git a/example/src/main/java/io/netty/example/http/websocketx/benchmarkserver/WebSocketServer.java b/example/src/main/java/io/netty/example/http/websocketx/benchmarkserver/WebSocketServer.java
index a344df8aa6a..a5df452cf31 100644
--- a/example/src/main/java/io/netty/example/http/websocketx/benchmarkserver/WebSocketServer.java
+++ b/example/src/main/java/io/netty/example/http/websocketx/benchmarkserver/WebSocketServer.java
@@ -18,7 +18,8 @@
 import io.netty.bootstrap.ServerBootstrap;
 import io.netty.channel.Channel;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.nio.NioServerSocketChannel;
 import io.netty.example.util.ServerUtil;
 import io.netty.handler.ssl.SslContext;
@@ -40,8 +41,8 @@ public static void main(String[] args) throws Exception {
         // Configure SSL.
         final SslContext sslCtx = ServerUtil.buildSslContext();
 
-        EventLoopGroup bossGroup = new NioEventLoopGroup(1);
-        EventLoopGroup workerGroup = new NioEventLoopGroup();
+        EventLoopGroup bossGroup = new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory());
+        EventLoopGroup workerGroup = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         try {
             ServerBootstrap b = new ServerBootstrap();
             b.group(bossGroup, workerGroup)
diff --git a/example/src/main/java/io/netty/example/http/websocketx/client/WebSocketClient.java b/example/src/main/java/io/netty/example/http/websocketx/client/WebSocketClient.java
index 5cfc62cba23..c1f7f2496bf 100644
--- a/example/src/main/java/io/netty/example/http/websocketx/client/WebSocketClient.java
+++ b/example/src/main/java/io/netty/example/http/websocketx/client/WebSocketClient.java
@@ -21,7 +21,8 @@
 import io.netty.channel.ChannelInitializer;
 import io.netty.channel.ChannelPipeline;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.SocketChannel;
 import io.netty.channel.socket.nio.NioSocketChannel;
 import io.netty.handler.codec.http.DefaultHttpHeaders;
@@ -90,7 +91,7 @@ public static void main(String[] args) throws Exception {
             sslCtx = null;
         }
 
-        EventLoopGroup group = new NioEventLoopGroup();
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         try {
             // Connect with V13 (RFC 6455 aka HyBi-17). You can change it to V08 or V00.
             // If you change it to V00, ping is not supported and remember to change
diff --git a/example/src/main/java/io/netty/example/http/websocketx/server/WebSocketServer.java b/example/src/main/java/io/netty/example/http/websocketx/server/WebSocketServer.java
index ad1e8efab4f..38cbdcb0996 100644
--- a/example/src/main/java/io/netty/example/http/websocketx/server/WebSocketServer.java
+++ b/example/src/main/java/io/netty/example/http/websocketx/server/WebSocketServer.java
@@ -18,7 +18,8 @@
 import io.netty.bootstrap.ServerBootstrap;
 import io.netty.channel.Channel;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.nio.NioServerSocketChannel;
 import io.netty.example.util.ServerUtil;
 import io.netty.handler.logging.LogLevel;
@@ -53,8 +54,8 @@ public static void main(String[] args) throws Exception {
         // Configure SSL.
         final SslContext sslCtx = ServerUtil.buildSslContext();
 
-        EventLoopGroup bossGroup = new NioEventLoopGroup(1);
-        EventLoopGroup workerGroup = new NioEventLoopGroup();
+        EventLoopGroup bossGroup = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
+        EventLoopGroup workerGroup = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         try {
             ServerBootstrap b = new ServerBootstrap();
             b.group(bossGroup, workerGroup)
diff --git a/example/src/main/java/io/netty/example/http2/file/Http2StaticFileServer.java b/example/src/main/java/io/netty/example/http2/file/Http2StaticFileServer.java
index 03a04b60a6a..9cc2cf4186d 100644
--- a/example/src/main/java/io/netty/example/http2/file/Http2StaticFileServer.java
+++ b/example/src/main/java/io/netty/example/http2/file/Http2StaticFileServer.java
@@ -18,7 +18,8 @@
 import io.netty.bootstrap.ServerBootstrap;
 import io.netty.channel.Channel;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.nio.NioServerSocketChannel;
 import io.netty.handler.codec.http2.Http2SecurityUtil;
 import io.netty.handler.logging.LogLevel;
@@ -50,8 +51,8 @@ public static void main(String[] args) throws Exception {
                         ApplicationProtocolNames.HTTP_1_1))
                 .build();
 
-        EventLoopGroup bossGroup = new NioEventLoopGroup(2);
-        EventLoopGroup workerGroup = new NioEventLoopGroup(4);
+        EventLoopGroup bossGroup = new MultiThreadIoEventLoopGroup(2, NioIoHandler.newFactory());
+        EventLoopGroup workerGroup = new MultiThreadIoEventLoopGroup(4, NioIoHandler.newFactory());
         try {
             ServerBootstrap b = new ServerBootstrap();
             b.group(bossGroup, workerGroup)
diff --git a/example/src/main/java/io/netty/example/http2/helloworld/client/Http2Client.java b/example/src/main/java/io/netty/example/http2/helloworld/client/Http2Client.java
index a987e7423c4..f8199481147 100644
--- a/example/src/main/java/io/netty/example/http2/helloworld/client/Http2Client.java
+++ b/example/src/main/java/io/netty/example/http2/helloworld/client/Http2Client.java
@@ -19,7 +19,8 @@
 import io.netty.channel.Channel;
 import io.netty.channel.ChannelOption;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.nio.NioSocketChannel;
 import io.netty.handler.codec.http.DefaultFullHttpRequest;
 import io.netty.handler.codec.http.FullHttpRequest;
@@ -91,13 +92,13 @@ public static void main(String[] args) throws Exception {
             sslCtx = null;
         }
 
-        EventLoopGroup workerGroup = new NioEventLoopGroup();
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         Http2ClientInitializer initializer = new Http2ClientInitializer(sslCtx, Integer.MAX_VALUE);
 
         try {
             // Configure the client.
             Bootstrap b = new Bootstrap();
-            b.group(workerGroup);
+            b.group(group);
             b.channel(NioSocketChannel.class);
             b.option(ChannelOption.SO_KEEPALIVE, true);
             b.remoteAddress(HOST, PORT);
@@ -143,7 +144,7 @@ public static void main(String[] args) throws Exception {
             // Wait until the connection is closed.
             channel.close().syncUninterruptibly();
         } finally {
-            workerGroup.shutdownGracefully();
+            group.shutdownGracefully();
         }
     }
 }
diff --git a/example/src/main/java/io/netty/example/http2/helloworld/frame/client/Http2FrameClient.java b/example/src/main/java/io/netty/example/http2/helloworld/frame/client/Http2FrameClient.java
index 8f87c986e1e..9d7508b65ea 100644
--- a/example/src/main/java/io/netty/example/http2/helloworld/frame/client/Http2FrameClient.java
+++ b/example/src/main/java/io/netty/example/http2/helloworld/frame/client/Http2FrameClient.java
@@ -18,7 +18,8 @@
 import io.netty.channel.Channel;
 import io.netty.channel.ChannelOption;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.nio.NioSocketChannel;
 import io.netty.handler.codec.http2.DefaultHttp2Headers;
 import io.netty.handler.codec.http2.DefaultHttp2HeadersFrame;
@@ -56,7 +57,7 @@ private Http2FrameClient() {
     }
 
     public static void main(String[] args) throws Exception {
-        final EventLoopGroup clientWorkerGroup = new NioEventLoopGroup();
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
 
         // Configure SSL.
         final SslContext sslCtx;
@@ -81,7 +82,7 @@ public static void main(String[] args) throws Exception {
 
         try {
             final Bootstrap b = new Bootstrap();
-            b.group(clientWorkerGroup);
+            b.group(group);
             b.channel(NioSocketChannel.class);
             b.option(ChannelOption.SO_KEEPALIVE, true);
             b.remoteAddress(HOST, PORT);
@@ -117,7 +118,7 @@ public static void main(String[] args) throws Exception {
             // Wait until the connection is closed.
             channel.close().syncUninterruptibly();
         } finally {
-            clientWorkerGroup.shutdownGracefully();
+            group.shutdownGracefully();
         }
     }
 
diff --git a/example/src/main/java/io/netty/example/http2/helloworld/frame/server/Http2Server.java b/example/src/main/java/io/netty/example/http2/helloworld/frame/server/Http2Server.java
index 2ba58748e69..05711c9ed80 100644
--- a/example/src/main/java/io/netty/example/http2/helloworld/frame/server/Http2Server.java
+++ b/example/src/main/java/io/netty/example/http2/helloworld/frame/server/Http2Server.java
@@ -20,7 +20,8 @@
 import io.netty.channel.Channel;
 import io.netty.channel.ChannelOption;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.nio.NioServerSocketChannel;
 import io.netty.handler.codec.http2.Http2SecurityUtil;
 import io.netty.handler.logging.LogLevel;
@@ -74,7 +75,7 @@ public static void main(String[] args) throws Exception {
             sslCtx = null;
         }
         // Configure the server.
-        EventLoopGroup group = new NioEventLoopGroup();
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         try {
             ServerBootstrap b = new ServerBootstrap();
             b.option(ChannelOption.SO_BACKLOG, 1024);
diff --git a/example/src/main/java/io/netty/example/http2/helloworld/multiplex/server/Http2Server.java b/example/src/main/java/io/netty/example/http2/helloworld/multiplex/server/Http2Server.java
index 52ad4785e11..e099393f186 100644
--- a/example/src/main/java/io/netty/example/http2/helloworld/multiplex/server/Http2Server.java
+++ b/example/src/main/java/io/netty/example/http2/helloworld/multiplex/server/Http2Server.java
@@ -20,7 +20,8 @@
 import io.netty.channel.Channel;
 import io.netty.channel.ChannelOption;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.nio.NioServerSocketChannel;
 import io.netty.handler.codec.http2.Http2SecurityUtil;
 import io.netty.handler.logging.LogLevel;
@@ -74,7 +75,7 @@ public static void main(String[] args) throws Exception {
             sslCtx = null;
         }
         // Configure the server.
-        EventLoopGroup group = new NioEventLoopGroup();
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         try {
             ServerBootstrap b = new ServerBootstrap();
             b.option(ChannelOption.SO_BACKLOG, 1024);
diff --git a/example/src/main/java/io/netty/example/http2/helloworld/server/Http2Server.java b/example/src/main/java/io/netty/example/http2/helloworld/server/Http2Server.java
index 05a41c6491f..219bd5dd3f1 100644
--- a/example/src/main/java/io/netty/example/http2/helloworld/server/Http2Server.java
+++ b/example/src/main/java/io/netty/example/http2/helloworld/server/Http2Server.java
@@ -20,7 +20,8 @@
 import io.netty.channel.Channel;
 import io.netty.channel.ChannelOption;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.nio.NioServerSocketChannel;
 import io.netty.handler.codec.http2.Http2SecurityUtil;
 import io.netty.handler.logging.LogLevel;
@@ -71,7 +72,7 @@ public static void main(String[] args) throws Exception {
             sslCtx = null;
         }
         // Configure the server.
-        EventLoopGroup group = new NioEventLoopGroup();
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         try {
             ServerBootstrap b = new ServerBootstrap();
             b.option(ChannelOption.SO_BACKLOG, 1024);
diff --git a/example/src/main/java/io/netty/example/http2/tiles/Launcher.java b/example/src/main/java/io/netty/example/http2/tiles/Launcher.java
index a375a4fa359..15904528ba4 100644
--- a/example/src/main/java/io/netty/example/http2/tiles/Launcher.java
+++ b/example/src/main/java/io/netty/example/http2/tiles/Launcher.java
@@ -17,7 +17,8 @@
 package io.netty.example.http2.tiles;
 
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 
 /**
  * <p>
@@ -38,7 +39,7 @@
 public final class Launcher {
 
     public static void main(String[] args) {
-        EventLoopGroup group = new NioEventLoopGroup();
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         Http2Server http2 = new Http2Server(group);
         HttpServer http = new HttpServer(group);
         try {
diff --git a/example/src/main/java/io/netty/example/ipfilter/IpSubnetFilterExample.java b/example/src/main/java/io/netty/example/ipfilter/IpSubnetFilterExample.java
index 5d69e8724fd..56341321d38 100644
--- a/example/src/main/java/io/netty/example/ipfilter/IpSubnetFilterExample.java
+++ b/example/src/main/java/io/netty/example/ipfilter/IpSubnetFilterExample.java
@@ -22,8 +22,9 @@
 import io.netty.channel.ChannelInitializer;
 import io.netty.channel.ChannelPipeline;
 import io.netty.channel.EventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
 import io.netty.channel.SimpleChannelInboundHandler;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.SocketChannel;
 import io.netty.channel.socket.nio.NioServerSocketChannel;
 import io.netty.handler.ipfilter.IpFilterRuleType;
@@ -43,8 +44,8 @@ public final class IpSubnetFilterExample {
     static final int PORT = Integer.parseInt(System.getProperty("port", "8009"));
 
     public static void main(String[] args) throws Exception {
-        EventLoopGroup bossGroup = new NioEventLoopGroup(1);
-        EventLoopGroup workerGroup = new NioEventLoopGroup(1);
+        EventLoopGroup bossGroup = new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory());
+        EventLoopGroup workerGroup = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
 
         try {
             List<IpSubnetFilterRule> rules = new ArrayList<IpSubnetFilterRule>();
diff --git a/example/src/main/java/io/netty/example/localecho/LocalEcho.java b/example/src/main/java/io/netty/example/localecho/LocalEcho.java
index a567a744051..4f4fcf27958 100644
--- a/example/src/main/java/io/netty/example/localecho/LocalEcho.java
+++ b/example/src/main/java/io/netty/example/localecho/LocalEcho.java
@@ -20,12 +20,12 @@
 import io.netty.channel.Channel;
 import io.netty.channel.ChannelFuture;
 import io.netty.channel.ChannelInitializer;
-import io.netty.channel.DefaultEventLoopGroup;
 import io.netty.channel.EventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
 import io.netty.channel.local.LocalAddress;
 import io.netty.channel.local.LocalChannel;
+import io.netty.channel.local.LocalIoHandler;
 import io.netty.channel.local.LocalServerChannel;
-import io.netty.channel.nio.NioEventLoopGroup;
 import io.netty.handler.logging.LogLevel;
 import io.netty.handler.logging.LoggingHandler;
 
@@ -40,8 +40,8 @@ public static void main(String[] args) throws Exception {
         // Address to bind on / connect to.
         final LocalAddress addr = new LocalAddress(PORT);
 
-        EventLoopGroup serverGroup = new DefaultEventLoopGroup();
-        EventLoopGroup clientGroup = new NioEventLoopGroup(); // NIO event loops are also OK
+        EventLoopGroup serverGroup = new MultiThreadIoEventLoopGroup(LocalIoHandler.newFactory());
+        EventLoopGroup clientGroup =  new MultiThreadIoEventLoopGroup(LocalIoHandler.newFactory());
         try {
             // Note that we can use any event loop to ensure certain local channels
             // are handled by the same event loop thread which drives a certain socket channel
diff --git a/example/src/main/java/io/netty/example/memcache/binary/MemcacheClient.java b/example/src/main/java/io/netty/example/memcache/binary/MemcacheClient.java
index 1b01fb57c59..b434c7dea55 100644
--- a/example/src/main/java/io/netty/example/memcache/binary/MemcacheClient.java
+++ b/example/src/main/java/io/netty/example/memcache/binary/MemcacheClient.java
@@ -21,7 +21,8 @@
 import io.netty.channel.ChannelInitializer;
 import io.netty.channel.ChannelPipeline;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.SocketChannel;
 import io.netty.channel.socket.nio.NioSocketChannel;
 import io.netty.handler.codec.memcache.binary.BinaryMemcacheClientCodec;
@@ -52,7 +53,7 @@ public static void main(String[] args) throws Exception {
             sslCtx = null;
         }
 
-        EventLoopGroup group = new NioEventLoopGroup();
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         try {
             Bootstrap b = new Bootstrap();
             b.group(group)
diff --git a/example/src/main/java/io/netty/example/mqtt/heartBeat/MqttHeartBeatBroker.java b/example/src/main/java/io/netty/example/mqtt/heartBeat/MqttHeartBeatBroker.java
index 66777f9da70..4de602a0538 100644
--- a/example/src/main/java/io/netty/example/mqtt/heartBeat/MqttHeartBeatBroker.java
+++ b/example/src/main/java/io/netty/example/mqtt/heartBeat/MqttHeartBeatBroker.java
@@ -20,7 +20,8 @@
 import io.netty.channel.ChannelInitializer;
 import io.netty.channel.ChannelOption;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.SocketChannel;
 import io.netty.channel.socket.nio.NioServerSocketChannel;
 import io.netty.handler.codec.mqtt.MqttDecoder;
@@ -35,8 +36,8 @@ private MqttHeartBeatBroker() {
     }
 
     public static void main(String[] args) throws Exception {
-        EventLoopGroup bossGroup = new NioEventLoopGroup(1);
-        EventLoopGroup workerGroup = new NioEventLoopGroup();
+        EventLoopGroup bossGroup = new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory());
+        EventLoopGroup workerGroup = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
 
         try {
             ServerBootstrap b = new ServerBootstrap();
diff --git a/example/src/main/java/io/netty/example/mqtt/heartBeat/MqttHeartBeatClient.java b/example/src/main/java/io/netty/example/mqtt/heartBeat/MqttHeartBeatClient.java
index 3d64523ff7c..e799a0da95a 100644
--- a/example/src/main/java/io/netty/example/mqtt/heartBeat/MqttHeartBeatClient.java
+++ b/example/src/main/java/io/netty/example/mqtt/heartBeat/MqttHeartBeatClient.java
@@ -19,7 +19,8 @@
 import io.netty.channel.ChannelFuture;
 import io.netty.channel.ChannelInitializer;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.SocketChannel;
 import io.netty.channel.socket.nio.NioSocketChannel;
 import io.netty.handler.codec.mqtt.MqttDecoder;
@@ -39,11 +40,11 @@ private MqttHeartBeatClient() {
     private static final String PASSWORD = System.getProperty("password", "guest");
 
     public static void main(String[] args) throws Exception {
-        EventLoopGroup workerGroup = new NioEventLoopGroup();
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
 
         try {
             Bootstrap b = new Bootstrap();
-            b.group(workerGroup);
+            b.group(group);
             b.channel(NioSocketChannel.class);
             b.handler(new ChannelInitializer<SocketChannel>() {
                 @Override
@@ -59,7 +60,7 @@ protected void initChannel(SocketChannel ch) throws Exception {
             System.out.println("Client connected");
             f.channel().closeFuture().sync();
         } finally {
-            workerGroup.shutdownGracefully();
+            group.shutdownGracefully();
         }
     }
 }
diff --git a/example/src/main/java/io/netty/example/objectecho/ObjectEchoClient.java b/example/src/main/java/io/netty/example/objectecho/ObjectEchoClient.java
index 2d6985cd86d..37929de9b11 100644
--- a/example/src/main/java/io/netty/example/objectecho/ObjectEchoClient.java
+++ b/example/src/main/java/io/netty/example/objectecho/ObjectEchoClient.java
@@ -19,7 +19,8 @@
 import io.netty.channel.ChannelInitializer;
 import io.netty.channel.ChannelPipeline;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.SocketChannel;
 import io.netty.channel.socket.nio.NioSocketChannel;
 import io.netty.example.echo.EchoClient;
@@ -50,7 +51,7 @@ public static void main(String[] args) throws Exception {
             sslCtx = null;
         }
 
-        EventLoopGroup group = new NioEventLoopGroup();
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         try {
             Bootstrap b = new Bootstrap();
             b.group(group)
diff --git a/example/src/main/java/io/netty/example/objectecho/ObjectEchoServer.java b/example/src/main/java/io/netty/example/objectecho/ObjectEchoServer.java
index b8778696bcc..25b40f243ec 100644
--- a/example/src/main/java/io/netty/example/objectecho/ObjectEchoServer.java
+++ b/example/src/main/java/io/netty/example/objectecho/ObjectEchoServer.java
@@ -19,7 +19,8 @@
 import io.netty.channel.ChannelInitializer;
 import io.netty.channel.ChannelPipeline;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.SocketChannel;
 import io.netty.channel.socket.nio.NioServerSocketChannel;
 import io.netty.example.echo.EchoServer;
@@ -43,8 +44,8 @@ public static void main(String[] args) throws Exception {
         // Configure SSL.
         final SslContext sslCtx = ServerUtil.buildSslContext();
 
-        EventLoopGroup bossGroup = new NioEventLoopGroup(1);
-        EventLoopGroup workerGroup = new NioEventLoopGroup();
+        EventLoopGroup bossGroup = new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory());
+        EventLoopGroup workerGroup = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         try {
             ServerBootstrap b = new ServerBootstrap();
             b.group(bossGroup, workerGroup)
diff --git a/example/src/main/java/io/netty/example/ocsp/OcspClientExample.java b/example/src/main/java/io/netty/example/ocsp/OcspClientExample.java
index c5b11edca7a..854de0bdd67 100644
--- a/example/src/main/java/io/netty/example/ocsp/OcspClientExample.java
+++ b/example/src/main/java/io/netty/example/ocsp/OcspClientExample.java
@@ -22,6 +22,8 @@
 import javax.security.cert.X509Certificate;
 
 import io.netty.buffer.Unpooled;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import org.bouncycastle.asn1.ocsp.OCSPResponseStatus;
 import org.bouncycastle.cert.ocsp.BasicOCSPResp;
 import org.bouncycastle.cert.ocsp.CertificateStatus;
@@ -37,7 +39,6 @@
 import io.netty.channel.ChannelOption;
 import io.netty.channel.ChannelPipeline;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
 import io.netty.channel.socket.nio.NioSocketChannel;
 import io.netty.handler.codec.http.DefaultFullHttpRequest;
 import io.netty.handler.codec.http.FullHttpRequest;
@@ -88,7 +89,7 @@ public static void main(String[] args) throws Exception {
                 .build();
 
         try {
-            EventLoopGroup group = new NioEventLoopGroup();
+            EventLoopGroup group = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
             try {
                 Promise<FullHttpResponse> promise = group.next().newPromise();
 
diff --git a/example/src/main/java/io/netty/example/portunification/PortUnificationServer.java b/example/src/main/java/io/netty/example/portunification/PortUnificationServer.java
index eae62892257..02f92113f4a 100644
--- a/example/src/main/java/io/netty/example/portunification/PortUnificationServer.java
+++ b/example/src/main/java/io/netty/example/portunification/PortUnificationServer.java
@@ -18,7 +18,8 @@
 import io.netty.bootstrap.ServerBootstrap;
 import io.netty.channel.ChannelInitializer;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.SocketChannel;
 import io.netty.channel.socket.nio.NioServerSocketChannel;
 import io.netty.handler.logging.LogLevel;
@@ -44,8 +45,8 @@ public static void main(String[] args) throws Exception {
         final SslContext sslCtx = SslContextBuilder.forServer(ssc.certificate(), ssc.privateKey())
             .build();
 
-        EventLoopGroup bossGroup = new NioEventLoopGroup(1);
-        EventLoopGroup workerGroup = new NioEventLoopGroup();
+        EventLoopGroup bossGroup = new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory());
+        EventLoopGroup workerGroup = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         try {
             ServerBootstrap b = new ServerBootstrap();
             b.group(bossGroup, workerGroup)
diff --git a/example/src/main/java/io/netty/example/proxy/HexDumpProxy.java b/example/src/main/java/io/netty/example/proxy/HexDumpProxy.java
index c57515ea8f1..e33e29ba85a 100644
--- a/example/src/main/java/io/netty/example/proxy/HexDumpProxy.java
+++ b/example/src/main/java/io/netty/example/proxy/HexDumpProxy.java
@@ -18,7 +18,8 @@
 import io.netty.bootstrap.ServerBootstrap;
 import io.netty.channel.ChannelOption;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.nio.NioServerSocketChannel;
 import io.netty.handler.logging.LogLevel;
 import io.netty.handler.logging.LoggingHandler;
@@ -33,8 +34,8 @@ public static void main(String[] args) throws Exception {
         System.err.println("Proxying *:" + LOCAL_PORT + " to " + REMOTE_HOST + ':' + REMOTE_PORT + " ...");
 
         // Configure the bootstrap.
-        EventLoopGroup bossGroup = new NioEventLoopGroup(1);
-        EventLoopGroup workerGroup = new NioEventLoopGroup();
+        EventLoopGroup bossGroup = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
+        EventLoopGroup workerGroup = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         try {
             ServerBootstrap b = new ServerBootstrap();
             b.group(bossGroup, workerGroup)
diff --git a/example/src/main/java/io/netty/example/qotm/QuoteOfTheMomentClient.java b/example/src/main/java/io/netty/example/qotm/QuoteOfTheMomentClient.java
index 68594a82893..f00747b289b 100644
--- a/example/src/main/java/io/netty/example/qotm/QuoteOfTheMomentClient.java
+++ b/example/src/main/java/io/netty/example/qotm/QuoteOfTheMomentClient.java
@@ -20,7 +20,8 @@
 import io.netty.channel.Channel;
 import io.netty.channel.ChannelOption;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.DatagramPacket;
 import io.netty.channel.socket.nio.NioDatagramChannel;
 import io.netty.util.CharsetUtil;
@@ -38,7 +39,7 @@ public final class QuoteOfTheMomentClient {
 
     public static void main(String[] args) throws Exception {
 
-        EventLoopGroup group = new NioEventLoopGroup();
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         try {
             Bootstrap b = new Bootstrap();
             b.group(group)
diff --git a/example/src/main/java/io/netty/example/qotm/QuoteOfTheMomentServer.java b/example/src/main/java/io/netty/example/qotm/QuoteOfTheMomentServer.java
index 46ef1932585..ee44ab2a442 100644
--- a/example/src/main/java/io/netty/example/qotm/QuoteOfTheMomentServer.java
+++ b/example/src/main/java/io/netty/example/qotm/QuoteOfTheMomentServer.java
@@ -18,7 +18,8 @@
 import io.netty.bootstrap.Bootstrap;
 import io.netty.channel.ChannelOption;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.nio.NioDatagramChannel;
 
 /**
@@ -32,7 +33,7 @@ public final class QuoteOfTheMomentServer {
     private static final int PORT = Integer.parseInt(System.getProperty("port", "7686"));
 
     public static void main(String[] args) throws Exception {
-        EventLoopGroup group = new NioEventLoopGroup();
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         try {
             Bootstrap b = new Bootstrap();
             b.group(group)
diff --git a/example/src/main/java/io/netty/example/redis/RedisClient.java b/example/src/main/java/io/netty/example/redis/RedisClient.java
index 50718b11243..c8b211da9bb 100644
--- a/example/src/main/java/io/netty/example/redis/RedisClient.java
+++ b/example/src/main/java/io/netty/example/redis/RedisClient.java
@@ -21,7 +21,8 @@
 import io.netty.channel.ChannelInitializer;
 import io.netty.channel.ChannelPipeline;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.SocketChannel;
 import io.netty.channel.socket.nio.NioSocketChannel;
 import io.netty.handler.codec.redis.RedisArrayAggregator;
@@ -41,7 +42,7 @@ public class RedisClient {
     private static final int PORT = Integer.parseInt(System.getProperty("port", "6379"));
 
     public static void main(String[] args) throws Exception {
-        EventLoopGroup group = new NioEventLoopGroup();
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         try {
             Bootstrap b = new Bootstrap();
             b.group(group)
diff --git a/example/src/main/java/io/netty/example/sctp/SctpEchoClient.java b/example/src/main/java/io/netty/example/sctp/SctpEchoClient.java
index 1b5eca6cca7..202ebfb2044 100644
--- a/example/src/main/java/io/netty/example/sctp/SctpEchoClient.java
+++ b/example/src/main/java/io/netty/example/sctp/SctpEchoClient.java
@@ -19,7 +19,8 @@
 import io.netty.channel.ChannelFuture;
 import io.netty.channel.ChannelInitializer;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.sctp.SctpChannel;
 import io.netty.channel.sctp.SctpChannelOption;
 import io.netty.channel.sctp.nio.NioSctpChannel;
@@ -40,7 +41,7 @@ public final class SctpEchoClient {
 
     public static void main(String[] args) throws Exception {
         // Configure the client.
-        EventLoopGroup group = new NioEventLoopGroup();
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         try {
             Bootstrap b = new Bootstrap();
             b.group(group)
diff --git a/example/src/main/java/io/netty/example/sctp/SctpEchoServer.java b/example/src/main/java/io/netty/example/sctp/SctpEchoServer.java
index c3273c64d08..70ec1a24e7e 100644
--- a/example/src/main/java/io/netty/example/sctp/SctpEchoServer.java
+++ b/example/src/main/java/io/netty/example/sctp/SctpEchoServer.java
@@ -20,7 +20,8 @@
 import io.netty.channel.ChannelInitializer;
 import io.netty.channel.ChannelOption;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.sctp.SctpChannel;
 import io.netty.channel.sctp.nio.NioSctpServerChannel;
 import io.netty.handler.logging.LogLevel;
@@ -35,8 +36,8 @@ public final class SctpEchoServer {
 
     public static void main(String[] args) throws Exception {
         // Configure the server.
-        EventLoopGroup bossGroup = new NioEventLoopGroup(1);
-        EventLoopGroup workerGroup = new NioEventLoopGroup();
+        EventLoopGroup bossGroup = new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory());
+        EventLoopGroup workerGroup = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         final SctpEchoServerHandler serverHandler = new SctpEchoServerHandler();
         try {
             ServerBootstrap b = new ServerBootstrap();
diff --git a/example/src/main/java/io/netty/example/sctp/multihoming/SctpMultiHomingEchoClient.java b/example/src/main/java/io/netty/example/sctp/multihoming/SctpMultiHomingEchoClient.java
index 9b6dff684af..1d2260a1786 100644
--- a/example/src/main/java/io/netty/example/sctp/multihoming/SctpMultiHomingEchoClient.java
+++ b/example/src/main/java/io/netty/example/sctp/multihoming/SctpMultiHomingEchoClient.java
@@ -19,7 +19,8 @@
 import io.netty.channel.ChannelFuture;
 import io.netty.channel.ChannelInitializer;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.sctp.SctpChannel;
 import io.netty.channel.sctp.SctpChannelOption;
 import io.netty.channel.sctp.nio.NioSctpChannel;
@@ -44,7 +45,7 @@ public final class SctpMultiHomingEchoClient {
 
     public static void main(String[] args) throws Exception {
         // Configure the client.
-        EventLoopGroup group = new NioEventLoopGroup();
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         try {
             Bootstrap b = new Bootstrap();
             b.group(group)
diff --git a/example/src/main/java/io/netty/example/sctp/multihoming/SctpMultiHomingEchoServer.java b/example/src/main/java/io/netty/example/sctp/multihoming/SctpMultiHomingEchoServer.java
index c11cb09324b..6c64f945244 100644
--- a/example/src/main/java/io/netty/example/sctp/multihoming/SctpMultiHomingEchoServer.java
+++ b/example/src/main/java/io/netty/example/sctp/multihoming/SctpMultiHomingEchoServer.java
@@ -20,7 +20,8 @@
 import io.netty.channel.ChannelInitializer;
 import io.netty.channel.ChannelOption;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.sctp.SctpChannel;
 import io.netty.channel.sctp.SctpServerChannel;
 import io.netty.channel.sctp.nio.NioSctpServerChannel;
@@ -44,8 +45,8 @@ public final class SctpMultiHomingEchoServer {
 
     public static void main(String[] args) throws Exception {
         // Configure the server.
-        EventLoopGroup bossGroup = new NioEventLoopGroup(1);
-        EventLoopGroup workerGroup = new NioEventLoopGroup();
+        EventLoopGroup bossGroup = new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory());
+        EventLoopGroup workerGroup = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         try {
             ServerBootstrap b = new ServerBootstrap();
             b.group(bossGroup, workerGroup)
diff --git a/example/src/main/java/io/netty/example/securechat/SecureChatClient.java b/example/src/main/java/io/netty/example/securechat/SecureChatClient.java
index 2404c409547..e05dda6e645 100644
--- a/example/src/main/java/io/netty/example/securechat/SecureChatClient.java
+++ b/example/src/main/java/io/netty/example/securechat/SecureChatClient.java
@@ -19,7 +19,8 @@
 import io.netty.channel.Channel;
 import io.netty.channel.ChannelFuture;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.nio.NioSocketChannel;
 import io.netty.example.telnet.TelnetClient;
 import io.netty.handler.ssl.SslContext;
@@ -42,7 +43,7 @@ public static void main(String[] args) throws Exception {
         final SslContext sslCtx = SslContextBuilder.forClient()
             .trustManager(InsecureTrustManagerFactory.INSTANCE).build();
 
-        EventLoopGroup group = new NioEventLoopGroup();
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         try {
             Bootstrap b = new Bootstrap();
             b.group(group)
diff --git a/example/src/main/java/io/netty/example/securechat/SecureChatServer.java b/example/src/main/java/io/netty/example/securechat/SecureChatServer.java
index 5e5b7cfd2ed..a67d72042c8 100644
--- a/example/src/main/java/io/netty/example/securechat/SecureChatServer.java
+++ b/example/src/main/java/io/netty/example/securechat/SecureChatServer.java
@@ -17,7 +17,8 @@
 
 import io.netty.bootstrap.ServerBootstrap;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.nio.NioServerSocketChannel;
 import io.netty.example.telnet.TelnetServer;
 import io.netty.handler.logging.LogLevel;
@@ -38,8 +39,8 @@ public static void main(String[] args) throws Exception {
         SslContext sslCtx = SslContextBuilder.forServer(ssc.certificate(), ssc.privateKey())
             .build();
 
-        EventLoopGroup bossGroup = new NioEventLoopGroup(1);
-        EventLoopGroup workerGroup = new NioEventLoopGroup();
+        EventLoopGroup bossGroup = new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory());
+        EventLoopGroup workerGroup = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         try {
             ServerBootstrap b = new ServerBootstrap();
             b.group(bossGroup, workerGroup)
diff --git a/example/src/main/java/io/netty/example/socksproxy/SocksServer.java b/example/src/main/java/io/netty/example/socksproxy/SocksServer.java
index 6c284f8831e..b226a0e3d8c 100644
--- a/example/src/main/java/io/netty/example/socksproxy/SocksServer.java
+++ b/example/src/main/java/io/netty/example/socksproxy/SocksServer.java
@@ -17,7 +17,8 @@
 
 import io.netty.bootstrap.ServerBootstrap;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.nio.NioServerSocketChannel;
 import io.netty.handler.logging.LogLevel;
 import io.netty.handler.logging.LoggingHandler;
@@ -27,8 +28,8 @@ public final class SocksServer {
     static final int PORT = Integer.parseInt(System.getProperty("port", "1080"));
 
     public static void main(String[] args) throws Exception {
-        EventLoopGroup bossGroup = new NioEventLoopGroup(1);
-        EventLoopGroup workerGroup = new NioEventLoopGroup();
+        EventLoopGroup bossGroup = new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory());
+        EventLoopGroup workerGroup = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         try {
             ServerBootstrap b = new ServerBootstrap();
             b.group(bossGroup, workerGroup)
diff --git a/example/src/main/java/io/netty/example/spdy/client/SpdyClient.java b/example/src/main/java/io/netty/example/spdy/client/SpdyClient.java
index cb477a108d3..56077187d3c 100644
--- a/example/src/main/java/io/netty/example/spdy/client/SpdyClient.java
+++ b/example/src/main/java/io/netty/example/spdy/client/SpdyClient.java
@@ -20,7 +20,8 @@
 import io.netty.channel.Channel;
 import io.netty.channel.ChannelOption;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.nio.NioSocketChannel;
 import io.netty.handler.codec.http.DefaultFullHttpRequest;
 import io.netty.handler.codec.http.HttpHeaderNames;
@@ -70,11 +71,11 @@ public static void main(String[] args) throws Exception {
             .build();
 
         HttpResponseClientHandler httpResponseHandler = new HttpResponseClientHandler();
-        EventLoopGroup workerGroup = new NioEventLoopGroup();
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
 
         try {
             Bootstrap b = new Bootstrap();
-            b.group(workerGroup);
+            b.group(group);
             b.channel(NioSocketChannel.class);
             b.option(ChannelOption.SO_KEEPALIVE, true);
             b.remoteAddress(HOST, PORT);
@@ -100,7 +101,7 @@ public static void main(String[] args) throws Exception {
             // Wait until the connection is closed.
             channel.close().syncUninterruptibly();
         } finally {
-            workerGroup.shutdownGracefully();
+            group.shutdownGracefully();
         }
     }
 }
diff --git a/example/src/main/java/io/netty/example/spdy/server/SpdyServer.java b/example/src/main/java/io/netty/example/spdy/server/SpdyServer.java
index 40adeeb4f84..a2b090aa03b 100644
--- a/example/src/main/java/io/netty/example/spdy/server/SpdyServer.java
+++ b/example/src/main/java/io/netty/example/spdy/server/SpdyServer.java
@@ -19,7 +19,8 @@
 import io.netty.channel.Channel;
 import io.netty.channel.ChannelOption;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.nio.NioServerSocketChannel;
 import io.netty.handler.logging.LogLevel;
 import io.netty.handler.logging.LoggingHandler;
@@ -69,8 +70,8 @@ public static void main(String[] args) throws Exception {
             .build();
 
         // Configure the server.
-        EventLoopGroup bossGroup = new NioEventLoopGroup(1);
-        EventLoopGroup workerGroup = new NioEventLoopGroup();
+        EventLoopGroup bossGroup = new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory());
+        EventLoopGroup workerGroup = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         try {
             ServerBootstrap b = new ServerBootstrap();
             b.option(ChannelOption.SO_BACKLOG, 1024);
diff --git a/example/src/main/java/io/netty/example/stomp/StompClient.java b/example/src/main/java/io/netty/example/stomp/StompClient.java
index 9606027ee7c..f8320a50cea 100644
--- a/example/src/main/java/io/netty/example/stomp/StompClient.java
+++ b/example/src/main/java/io/netty/example/stomp/StompClient.java
@@ -19,7 +19,8 @@
 import io.netty.channel.ChannelInitializer;
 import io.netty.channel.ChannelPipeline;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.SocketChannel;
 import io.netty.channel.socket.nio.NioSocketChannel;
 import io.netty.handler.codec.stomp.StompSubframeAggregator;
@@ -41,7 +42,7 @@ public final class StompClient {
     static final String TOPIC = System.getProperty("topic", "jms.topic.exampleTopic");
 
     public static void main(String[] args) throws Exception {
-        EventLoopGroup group = new NioEventLoopGroup();
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         try {
             Bootstrap b = new Bootstrap();
             b.group(group).channel(NioSocketChannel.class);
diff --git a/example/src/main/java/io/netty/example/stomp/websocket/StompWebSocketChatServer.java b/example/src/main/java/io/netty/example/stomp/websocket/StompWebSocketChatServer.java
index a67edfbe53b..3b5e5cd10c3 100644
--- a/example/src/main/java/io/netty/example/stomp/websocket/StompWebSocketChatServer.java
+++ b/example/src/main/java/io/netty/example/stomp/websocket/StompWebSocketChatServer.java
@@ -18,7 +18,9 @@
 import io.netty.bootstrap.ServerBootstrap;
 import io.netty.channel.ChannelFuture;
 import io.netty.channel.ChannelFutureListener;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.EventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.nio.NioServerSocketChannel;
 
 public class StompWebSocketChatServer {
@@ -26,11 +28,11 @@ public class StompWebSocketChatServer {
     static final int PORT = Integer.parseInt(System.getProperty("port", "8080"));
 
     public void start(final int port) throws Exception {
-        NioEventLoopGroup boosGroup = new NioEventLoopGroup(1);
-        NioEventLoopGroup workerGroup = new NioEventLoopGroup();
+        EventLoopGroup bossGroup = new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory());
+        EventLoopGroup workerGroup = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         try {
             ServerBootstrap bootstrap = new ServerBootstrap()
-                    .group(boosGroup, workerGroup)
+                    .group(bossGroup, workerGroup)
                     .channel(NioServerSocketChannel.class)
                     .childHandler(new StompWebSocketChatServerInitializer("/chat"));
             bootstrap.bind(port).addListener(new ChannelFutureListener() {
@@ -44,7 +46,7 @@ public void operationComplete(ChannelFuture future) {
                 }
             }).channel().closeFuture().sync();
         } finally {
-            boosGroup.shutdownGracefully();
+            bossGroup.shutdownGracefully();
             workerGroup.shutdownGracefully();
         }
     }
diff --git a/example/src/main/java/io/netty/example/telnet/TelnetClient.java b/example/src/main/java/io/netty/example/telnet/TelnetClient.java
index f75354cfc0b..3aba7e2059e 100644
--- a/example/src/main/java/io/netty/example/telnet/TelnetClient.java
+++ b/example/src/main/java/io/netty/example/telnet/TelnetClient.java
@@ -19,7 +19,8 @@
 import io.netty.channel.Channel;
 import io.netty.channel.ChannelFuture;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.nio.NioSocketChannel;
 import io.netty.example.util.ServerUtil;
 import io.netty.handler.ssl.SslContext;
@@ -40,7 +41,7 @@ public static void main(String[] args) throws Exception {
         // Configure SSL.
         final SslContext sslCtx = ServerUtil.buildSslContext();
 
-        EventLoopGroup group = new NioEventLoopGroup();
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         try {
             Bootstrap b = new Bootstrap();
             b.group(group)
diff --git a/example/src/main/java/io/netty/example/telnet/TelnetServer.java b/example/src/main/java/io/netty/example/telnet/TelnetServer.java
index 5d0674542ad..f72ac161b45 100644
--- a/example/src/main/java/io/netty/example/telnet/TelnetServer.java
+++ b/example/src/main/java/io/netty/example/telnet/TelnetServer.java
@@ -17,7 +17,8 @@
 
 import io.netty.bootstrap.ServerBootstrap;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.nio.NioServerSocketChannel;
 import io.netty.example.util.ServerUtil;
 import io.netty.handler.logging.LogLevel;
@@ -36,8 +37,8 @@ public static void main(String[] args) throws Exception {
         // Configure SSL.
         final SslContext sslCtx = ServerUtil.buildSslContext();
 
-        EventLoopGroup bossGroup = new NioEventLoopGroup(1);
-        EventLoopGroup workerGroup = new NioEventLoopGroup();
+        EventLoopGroup bossGroup = new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory());
+        EventLoopGroup workerGroup = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         try {
             ServerBootstrap b = new ServerBootstrap();
             b.group(bossGroup, workerGroup)
diff --git a/example/src/main/java/io/netty/example/udt/echo/bytes/ByteEchoClient.java b/example/src/main/java/io/netty/example/udt/echo/bytes/ByteEchoClient.java
index 73381e98815..eba4a1e5862 100644
--- a/example/src/main/java/io/netty/example/udt/echo/bytes/ByteEchoClient.java
+++ b/example/src/main/java/io/netty/example/udt/echo/bytes/ByteEchoClient.java
@@ -18,7 +18,9 @@
 import io.netty.bootstrap.Bootstrap;
 import io.netty.channel.ChannelFuture;
 import io.netty.channel.ChannelInitializer;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.EventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.udt.UdtChannel;
 import io.netty.channel.udt.nio.NioUdtProvider;
 import io.netty.handler.logging.LogLevel;
@@ -44,8 +46,8 @@ public final class ByteEchoClient {
     public static void main(String[] args) throws Exception {
         // Configure the client.
         final ThreadFactory connectFactory = new DefaultThreadFactory("connect");
-        final NioEventLoopGroup connectGroup = new NioEventLoopGroup(1,
-                connectFactory, NioUdtProvider.BYTE_PROVIDER);
+        final EventLoopGroup connectGroup = new MultiThreadIoEventLoopGroup(1,
+                connectFactory, NioIoHandler.newFactory(NioUdtProvider.BYTE_PROVIDER));
         try {
             final Bootstrap boot = new Bootstrap();
             boot.group(connectGroup)
diff --git a/example/src/main/java/io/netty/example/udt/echo/bytes/ByteEchoServer.java b/example/src/main/java/io/netty/example/udt/echo/bytes/ByteEchoServer.java
index 750ec663f33..92173e99899 100644
--- a/example/src/main/java/io/netty/example/udt/echo/bytes/ByteEchoServer.java
+++ b/example/src/main/java/io/netty/example/udt/echo/bytes/ByteEchoServer.java
@@ -19,7 +19,9 @@
 import io.netty.channel.ChannelFuture;
 import io.netty.channel.ChannelInitializer;
 import io.netty.channel.ChannelOption;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.EventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.udt.UdtChannel;
 import io.netty.channel.udt.nio.NioUdtProvider;
 import io.netty.handler.logging.LogLevel;
@@ -40,8 +42,10 @@ public final class ByteEchoServer {
     public static void main(String[] args) throws Exception {
         final ThreadFactory acceptFactory = new DefaultThreadFactory("accept");
         final ThreadFactory connectFactory = new DefaultThreadFactory("connect");
-        final NioEventLoopGroup acceptGroup = new NioEventLoopGroup(1, acceptFactory, NioUdtProvider.BYTE_PROVIDER);
-        final NioEventLoopGroup connectGroup = new NioEventLoopGroup(1, connectFactory, NioUdtProvider.BYTE_PROVIDER);
+        final EventLoopGroup acceptGroup = new MultiThreadIoEventLoopGroup(
+                1, acceptFactory, NioIoHandler.newFactory(NioUdtProvider.BYTE_PROVIDER));
+        final EventLoopGroup connectGroup = new MultiThreadIoEventLoopGroup(
+                1, connectFactory, NioIoHandler.newFactory(NioUdtProvider.BYTE_PROVIDER));
 
         // Configure the server.
         try {
diff --git a/example/src/main/java/io/netty/example/udt/echo/message/MsgEchoClient.java b/example/src/main/java/io/netty/example/udt/echo/message/MsgEchoClient.java
index b2664ee421b..e2e4f7da75b 100644
--- a/example/src/main/java/io/netty/example/udt/echo/message/MsgEchoClient.java
+++ b/example/src/main/java/io/netty/example/udt/echo/message/MsgEchoClient.java
@@ -18,7 +18,9 @@
 import io.netty.bootstrap.Bootstrap;
 import io.netty.channel.ChannelFuture;
 import io.netty.channel.ChannelInitializer;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.EventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.udt.UdtChannel;
 import io.netty.channel.udt.nio.NioUdtProvider;
 import io.netty.handler.logging.LogLevel;
@@ -48,8 +50,8 @@ public static void main(String[] args) throws Exception {
 
         // Configure the client.
         final ThreadFactory connectFactory = new DefaultThreadFactory("connect");
-        final NioEventLoopGroup connectGroup = new NioEventLoopGroup(1,
-                connectFactory, NioUdtProvider.MESSAGE_PROVIDER);
+        final EventLoopGroup connectGroup = new MultiThreadIoEventLoopGroup(1,
+                connectFactory, NioIoHandler.newFactory(NioUdtProvider.MESSAGE_PROVIDER));
         try {
             final Bootstrap boot = new Bootstrap();
             boot.group(connectGroup)
diff --git a/example/src/main/java/io/netty/example/udt/echo/message/MsgEchoServer.java b/example/src/main/java/io/netty/example/udt/echo/message/MsgEchoServer.java
index 14c56e19ac8..765f2a07f14 100644
--- a/example/src/main/java/io/netty/example/udt/echo/message/MsgEchoServer.java
+++ b/example/src/main/java/io/netty/example/udt/echo/message/MsgEchoServer.java
@@ -19,7 +19,9 @@
 import io.netty.channel.ChannelFuture;
 import io.netty.channel.ChannelInitializer;
 import io.netty.channel.ChannelOption;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.EventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.udt.UdtChannel;
 import io.netty.channel.udt.nio.NioUdtProvider;
 import io.netty.handler.logging.LogLevel;
@@ -40,10 +42,12 @@ public final class MsgEchoServer {
     public static void main(String[] args) throws Exception {
         final ThreadFactory acceptFactory = new DefaultThreadFactory("accept");
         final ThreadFactory connectFactory = new DefaultThreadFactory("connect");
-        final NioEventLoopGroup acceptGroup =
-                new NioEventLoopGroup(1, acceptFactory, NioUdtProvider.MESSAGE_PROVIDER);
-        final NioEventLoopGroup connectGroup =
-                new NioEventLoopGroup(1, connectFactory, NioUdtProvider.MESSAGE_PROVIDER);
+        final EventLoopGroup acceptGroup =
+                new MultiThreadIoEventLoopGroup(
+                        1, acceptFactory, NioIoHandler.newFactory(NioUdtProvider.MESSAGE_PROVIDER));
+        final EventLoopGroup connectGroup =
+                new MultiThreadIoEventLoopGroup(
+                        1, connectFactory, NioIoHandler.newFactory(NioUdtProvider.MESSAGE_PROVIDER));
 
         // Configure the server.
         try {
diff --git a/example/src/main/java/io/netty/example/udt/echo/rendezvous/MsgEchoPeerBase.java b/example/src/main/java/io/netty/example/udt/echo/rendezvous/MsgEchoPeerBase.java
index f48de0e7fe2..bba53deea85 100644
--- a/example/src/main/java/io/netty/example/udt/echo/rendezvous/MsgEchoPeerBase.java
+++ b/example/src/main/java/io/netty/example/udt/echo/rendezvous/MsgEchoPeerBase.java
@@ -18,7 +18,9 @@
 import io.netty.bootstrap.Bootstrap;
 import io.netty.channel.ChannelFuture;
 import io.netty.channel.ChannelInitializer;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.EventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.udt.UdtChannel;
 import io.netty.channel.udt.nio.NioUdtProvider;
 import io.netty.handler.logging.LogLevel;
@@ -49,8 +51,8 @@ protected MsgEchoPeerBase(final InetSocketAddress self, final InetSocketAddress
     public void run() throws Exception {
         // Configure the peer.
         final ThreadFactory connectFactory = new DefaultThreadFactory("rendezvous");
-        final NioEventLoopGroup connectGroup = new NioEventLoopGroup(1,
-                connectFactory, NioUdtProvider.MESSAGE_PROVIDER);
+        final EventLoopGroup connectGroup = new MultiThreadIoEventLoopGroup(1,
+                connectFactory, NioIoHandler.newFactory(NioUdtProvider.MESSAGE_PROVIDER));
         try {
             final Bootstrap boot = new Bootstrap();
             boot.group(connectGroup)
diff --git a/example/src/main/java/io/netty/example/udt/echo/rendezvousBytes/ByteEchoPeerBase.java b/example/src/main/java/io/netty/example/udt/echo/rendezvousBytes/ByteEchoPeerBase.java
index 8a93b4ced5d..b02b5f36173 100644
--- a/example/src/main/java/io/netty/example/udt/echo/rendezvousBytes/ByteEchoPeerBase.java
+++ b/example/src/main/java/io/netty/example/udt/echo/rendezvousBytes/ByteEchoPeerBase.java
@@ -18,7 +18,9 @@
 import io.netty.bootstrap.Bootstrap;
 import io.netty.channel.ChannelFuture;
 import io.netty.channel.ChannelInitializer;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.EventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.udt.UdtChannel;
 import io.netty.channel.udt.nio.NioUdtProvider;
 import io.netty.handler.logging.LogLevel;
@@ -51,8 +53,8 @@ public ByteEchoPeerBase(int messageSize, SocketAddress myAddress, SocketAddress
 
     public void run() throws Exception {
         final ThreadFactory connectFactory = new DefaultThreadFactory("rendezvous");
-        final NioEventLoopGroup connectGroup = new NioEventLoopGroup(1,
-                connectFactory, NioUdtProvider.BYTE_PROVIDER);
+        final EventLoopGroup connectGroup = new MultiThreadIoEventLoopGroup(1,
+                connectFactory, NioIoHandler.newFactory(NioUdtProvider.BYTE_PROVIDER));
         try {
             final Bootstrap bootstrap = new Bootstrap();
             bootstrap.group(connectGroup)
diff --git a/example/src/main/java/io/netty/example/uptime/UptimeClient.java b/example/src/main/java/io/netty/example/uptime/UptimeClient.java
index 4b55dd9da7d..c362ffad4db 100644
--- a/example/src/main/java/io/netty/example/uptime/UptimeClient.java
+++ b/example/src/main/java/io/netty/example/uptime/UptimeClient.java
@@ -20,7 +20,8 @@
 import io.netty.channel.ChannelFutureListener;
 import io.netty.channel.ChannelInitializer;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.SocketChannel;
 import io.netty.channel.socket.nio.NioSocketChannel;
 import io.netty.handler.timeout.IdleStateHandler;
@@ -44,7 +45,7 @@ public final class UptimeClient {
     private static final Bootstrap bs = new Bootstrap();
 
     public static void main(String[] args) throws Exception {
-        EventLoopGroup group = new NioEventLoopGroup();
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         bs.group(group)
                 .channel(NioSocketChannel.class)
                 .remoteAddress(HOST, PORT)
diff --git a/example/src/main/java/io/netty/example/uptime/UptimeServer.java b/example/src/main/java/io/netty/example/uptime/UptimeServer.java
index 919aa6f50d4..21b070700a1 100644
--- a/example/src/main/java/io/netty/example/uptime/UptimeServer.java
+++ b/example/src/main/java/io/netty/example/uptime/UptimeServer.java
@@ -19,7 +19,8 @@
 import io.netty.channel.ChannelFuture;
 import io.netty.channel.ChannelInitializer;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.SocketChannel;
 import io.netty.channel.socket.nio.NioServerSocketChannel;
 import io.netty.handler.logging.LogLevel;
@@ -38,8 +39,8 @@ private UptimeServer() {
 
     public static void main(String[] args) throws Exception {
 
-        EventLoopGroup bossGroup = new NioEventLoopGroup(1);
-        EventLoopGroup workerGroup = new NioEventLoopGroup();
+        EventLoopGroup bossGroup = new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory());
+        EventLoopGroup workerGroup = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         try {
             ServerBootstrap b = new ServerBootstrap();
             b.group(bossGroup, workerGroup)
diff --git a/example/src/main/java/io/netty/example/worldclock/WorldClockClient.java b/example/src/main/java/io/netty/example/worldclock/WorldClockClient.java
index c1b977f8282..dd0a27aeb26 100644
--- a/example/src/main/java/io/netty/example/worldclock/WorldClockClient.java
+++ b/example/src/main/java/io/netty/example/worldclock/WorldClockClient.java
@@ -18,7 +18,8 @@
 import io.netty.bootstrap.Bootstrap;
 import io.netty.channel.Channel;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.nio.NioSocketChannel;
 import io.netty.example.util.ServerUtil;
 import io.netty.handler.ssl.SslContext;
@@ -41,7 +42,7 @@ public static void main(String[] args) throws Exception {
         // Configure SSL.
         final SslContext sslCtx = ServerUtil.buildSslContext();
 
-        EventLoopGroup group = new NioEventLoopGroup();
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         try {
             Bootstrap b = new Bootstrap();
             b.group(group)
diff --git a/example/src/main/java/io/netty/example/worldclock/WorldClockServer.java b/example/src/main/java/io/netty/example/worldclock/WorldClockServer.java
index 9ac24a5002c..a35a4971a10 100644
--- a/example/src/main/java/io/netty/example/worldclock/WorldClockServer.java
+++ b/example/src/main/java/io/netty/example/worldclock/WorldClockServer.java
@@ -17,7 +17,8 @@
 
 import io.netty.bootstrap.ServerBootstrap;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.nio.NioServerSocketChannel;
 import io.netty.example.util.ServerUtil;
 import io.netty.handler.logging.LogLevel;
@@ -33,8 +34,8 @@ public final class WorldClockServer {
 
     public static void main(String[] args) throws Exception {
 
-        EventLoopGroup bossGroup = new NioEventLoopGroup(1);
-        EventLoopGroup workerGroup = new NioEventLoopGroup();
+        EventLoopGroup bossGroup = new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory());
+        EventLoopGroup workerGroup = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         try {
             ServerBootstrap b = new ServerBootstrap();
             b.group(bossGroup, workerGroup)
diff --git a/handler-proxy/src/test/java/io/netty/handler/proxy/ProxyHandlerTest.java b/handler-proxy/src/test/java/io/netty/handler/proxy/ProxyHandlerTest.java
index 9d7d695b407..ab7d540f600 100644
--- a/handler-proxy/src/test/java/io/netty/handler/proxy/ProxyHandlerTest.java
+++ b/handler-proxy/src/test/java/io/netty/handler/proxy/ProxyHandlerTest.java
@@ -29,8 +29,9 @@
 import io.netty.channel.ChannelOption;
 import io.netty.channel.ChannelPipeline;
 import io.netty.channel.EventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
 import io.netty.channel.SimpleChannelInboundHandler;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.SocketChannel;
 import io.netty.channel.socket.nio.NioSocketChannel;
 import io.netty.handler.codec.LineBasedFrameDecoder;
@@ -80,7 +81,8 @@ public class ProxyHandlerTest {
     private static final String BAD_USERNAME = "badUser";
     private static final String BAD_PASSWORD = "badPassword";
 
-    static final EventLoopGroup group = new NioEventLoopGroup(3, new DefaultThreadFactory("proxy", true));
+    static final EventLoopGroup group = new MultiThreadIoEventLoopGroup(
+            3, new DefaultThreadFactory("proxy", true), NioIoHandler.newFactory());
 
     static final SslContext serverSslCtx;
     static final SslContext clientSslCtx;
diff --git a/handler-ssl-ocsp/src/main/java/io/netty/handler/ssl/ocsp/IoTransport.java b/handler-ssl-ocsp/src/main/java/io/netty/handler/ssl/ocsp/IoTransport.java
index 85ded8a3a3d..2045154708b 100644
--- a/handler-ssl-ocsp/src/main/java/io/netty/handler/ssl/ocsp/IoTransport.java
+++ b/handler-ssl-ocsp/src/main/java/io/netty/handler/ssl/ocsp/IoTransport.java
@@ -17,8 +17,8 @@
 
 import io.netty.channel.ChannelFactory;
 import io.netty.channel.EventLoop;
-import io.netty.channel.nio.NioEventLoop;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.DatagramChannel;
 import io.netty.channel.socket.SocketChannel;
 import io.netty.channel.socket.nio.NioDatagramChannel;
@@ -36,10 +36,11 @@ public final class IoTransport {
     private final ChannelFactory<DatagramChannel> datagramChannel;
 
     /**
-     * Default {@link IoTransport} which uses {@link NioEventLoop}, {@link NioSocketChannel}
+     * Default {@link IoTransport} which uses {@link NioIoHandler}, {@link NioSocketChannel}
      * and {@link NioDatagramChannel}.
      */
-    public static final IoTransport DEFAULT = new IoTransport(new NioEventLoopGroup(1).next(),
+    public static final IoTransport DEFAULT = new IoTransport(
+            new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory()).next(),
             new ChannelFactory<SocketChannel>() {
                 @Override
                 public SocketChannel newChannel() {
diff --git a/handler-ssl-ocsp/src/test/java/io/netty/handler/ssl/ocsp/OcspServerCertificateValidatorTest.java b/handler-ssl-ocsp/src/test/java/io/netty/handler/ssl/ocsp/OcspServerCertificateValidatorTest.java
index 0be194159ce..a30779134ca 100644
--- a/handler-ssl-ocsp/src/test/java/io/netty/handler/ssl/ocsp/OcspServerCertificateValidatorTest.java
+++ b/handler-ssl-ocsp/src/test/java/io/netty/handler/ssl/ocsp/OcspServerCertificateValidatorTest.java
@@ -22,8 +22,9 @@
 import io.netty.channel.ChannelOption;
 import io.netty.channel.ChannelPipeline;
 import io.netty.channel.EventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
 import io.netty.channel.SimpleChannelInboundHandler;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.SocketChannel;
 import io.netty.channel.socket.nio.NioSocketChannel;
 import io.netty.handler.ssl.SslContext;
@@ -42,7 +43,7 @@ class OcspServerCertificateValidatorTest {
     @Test
     void connectUsingHttpAndValidateCertificateUsingOcspTest() throws Exception {
         final AtomicBoolean ocspStatus = new AtomicBoolean();
-        EventLoopGroup eventLoopGroup = new NioEventLoopGroup();
+        EventLoopGroup eventLoopGroup = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
 
         try {
             final CountDownLatch latch = new CountDownLatch(1);
diff --git a/handler/src/test/java/io/netty/handler/flow/FlowControlHandlerTest.java b/handler/src/test/java/io/netty/handler/flow/FlowControlHandlerTest.java
index dd45e640174..6caa9d41e4c 100644
--- a/handler/src/test/java/io/netty/handler/flow/FlowControlHandlerTest.java
+++ b/handler/src/test/java/io/netty/handler/flow/FlowControlHandlerTest.java
@@ -29,8 +29,9 @@
 import io.netty.channel.ChannelOption;
 import io.netty.channel.ChannelPipeline;
 import io.netty.channel.EventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
 import io.netty.channel.embedded.EmbeddedChannel;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.nio.NioServerSocketChannel;
 import io.netty.channel.socket.nio.NioSocketChannel;
 import io.netty.handler.codec.ByteToMessageDecoder;
@@ -62,7 +63,7 @@ public class FlowControlHandlerTest {
 
     @BeforeAll
     public static void init() {
-        GROUP = new NioEventLoopGroup();
+        GROUP = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
     }
 
     @AfterAll
diff --git a/handler/src/test/java/io/netty/handler/pcap/PcapWriteHandlerTest.java b/handler/src/test/java/io/netty/handler/pcap/PcapWriteHandlerTest.java
index b8f1bff98e7..2173bc9faf9 100644
--- a/handler/src/test/java/io/netty/handler/pcap/PcapWriteHandlerTest.java
+++ b/handler/src/test/java/io/netty/handler/pcap/PcapWriteHandlerTest.java
@@ -31,9 +31,10 @@
 import io.netty.channel.ChannelPromise;
 import io.netty.channel.DefaultChannelId;
 import io.netty.channel.EventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
 import io.netty.channel.SimpleChannelInboundHandler;
 import io.netty.channel.embedded.EmbeddedChannel;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.DatagramChannel;
 import io.netty.channel.socket.DatagramChannelConfig;
 import io.netty.channel.socket.DatagramPacket;
@@ -82,7 +83,7 @@ private static void udpV4(boolean sharedOutputStream) throws InterruptedExceptio
         InetSocketAddress serverAddr = new InetSocketAddress("127.0.0.1", 0);
         InetSocketAddress clientAddr = new InetSocketAddress("127.0.0.1", 0);
 
-        NioEventLoopGroup eventLoopGroup = new NioEventLoopGroup(2);
+        EventLoopGroup eventLoopGroup = new MultiThreadIoEventLoopGroup(2, NioIoHandler.newFactory());
 
         // We'll bootstrap a UDP Server to avoid "Network Unreachable errors" when sending UDP Packet.
         Bootstrap server = new Bootstrap()
@@ -187,8 +188,8 @@ public void tcpV4NonOutputStream() throws Exception {
     private static void tcpV4(final boolean sharedOutputStream) throws Exception {
         final ByteBuf byteBuf = Unpooled.buffer();
 
-        EventLoopGroup bossGroup = new NioEventLoopGroup(1);
-        EventLoopGroup clientGroup = new NioEventLoopGroup();
+        EventLoopGroup bossGroup = new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory());
+        EventLoopGroup clientGroup = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
 
         // Configure the echo server
         ServerBootstrap sb = new ServerBootstrap();
diff --git a/handler/src/test/java/io/netty/handler/ssl/OpenSslCertificateCompressionTest.java b/handler/src/test/java/io/netty/handler/ssl/OpenSslCertificateCompressionTest.java
index 9882c722aad..45bd06cf34b 100644
--- a/handler/src/test/java/io/netty/handler/ssl/OpenSslCertificateCompressionTest.java
+++ b/handler/src/test/java/io/netty/handler/ssl/OpenSslCertificateCompressionTest.java
@@ -22,10 +22,11 @@
 import io.netty.channel.ChannelInitializer;
 import io.netty.channel.ChannelPipeline;
 import io.netty.channel.EventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
 import io.netty.channel.SimpleChannelInboundHandler;
 import io.netty.channel.local.LocalAddress;
 import io.netty.channel.local.LocalChannel;
-import io.netty.channel.local.LocalEventLoopGroup;
+import io.netty.channel.local.LocalIoHandler;
 import io.netty.channel.local.LocalServerChannel;
 import io.netty.handler.ssl.util.InsecureTrustManagerFactory;
 import io.netty.handler.ssl.util.SelfSignedCertificate;
@@ -310,7 +311,7 @@ public void execute() throws Throwable {
     }
 
     public void runCertCompressionTest(SslContext clientSslContext, SslContext serverSslContext) throws Throwable {
-        EventLoopGroup group = new LocalEventLoopGroup();
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(LocalIoHandler.newFactory());
         Promise<Object> clientPromise = group.next().newPromise();
         Promise<Object> serverPromise = group.next().newPromise();
         try {
diff --git a/handler/src/test/java/io/netty/handler/ssl/ParameterizedSslHandlerTest.java b/handler/src/test/java/io/netty/handler/ssl/ParameterizedSslHandlerTest.java
index c3da0dc1baa..d0e6fb05d17 100644
--- a/handler/src/test/java/io/netty/handler/ssl/ParameterizedSslHandlerTest.java
+++ b/handler/src/test/java/io/netty/handler/ssl/ParameterizedSslHandlerTest.java
@@ -26,14 +26,15 @@
 import io.netty.channel.ChannelInboundHandlerAdapter;
 import io.netty.channel.ChannelInitializer;
 import io.netty.channel.ChannelOption;
-import io.netty.channel.DefaultEventLoopGroup;
 import io.netty.channel.EventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
 import io.netty.channel.ServerChannel;
 import io.netty.channel.SimpleChannelInboundHandler;
 import io.netty.channel.local.LocalAddress;
 import io.netty.channel.local.LocalChannel;
+import io.netty.channel.local.LocalIoHandler;
 import io.netty.channel.local.LocalServerChannel;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.nio.NioServerSocketChannel;
 import io.netty.channel.socket.nio.NioSocketChannel;
 import io.netty.handler.ssl.util.InsecureTrustManagerFactory;
@@ -46,6 +47,7 @@
 import io.netty.util.concurrent.Promise;
 import io.netty.util.concurrent.PromiseNotifier;
 import io.netty.util.internal.EmptyArrays;
+import io.netty.util.internal.PlatformDependent;
 import io.netty.util.internal.ResourcesUtil;
 import io.netty.util.internal.logging.InternalLogger;
 import io.netty.util.internal.logging.InternalLoggerFactory;
@@ -75,7 +77,6 @@
 import java.util.concurrent.atomic.AtomicBoolean;
 
 import static io.netty.buffer.ByteBufUtil.writeAscii;
-import static io.netty.util.internal.ThreadLocalRandom.current;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertTrue;
@@ -141,7 +142,7 @@ private static void compositeBufSizeEstimationGuaranteesSynchronousWrite(
                 .trustManager(InsecureTrustManagerFactory.INSTANCE)
                 .sslProvider(clientProvider).build();
 
-        EventLoopGroup group = new NioEventLoopGroup();
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         Channel sc = null;
         Channel cc = null;
         try {
@@ -323,7 +324,7 @@ public X509Certificate[] getAcceptedIssuers() {
                         ResourcesUtil.getFile(getClass(), "test_unencrypted.pem"))
                 .sslProvider(clientProvider).build();
 
-        NioEventLoopGroup group = new NioEventLoopGroup();
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         Channel sc = null;
         Channel cc = null;
         try {
@@ -423,7 +424,7 @@ private void testCloseNotify(SslProvider clientProvider, SslProvider serverProvi
                                                          .protocols(SslProtocols.TLS_v1_2)
                                                          .build();
 
-        EventLoopGroup group = new NioEventLoopGroup();
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         Channel sc = null;
         Channel cc = null;
         try {
@@ -524,7 +525,7 @@ public void operationComplete(Future<Channel> future) {
     @Timeout(value = 30000, unit = TimeUnit.MILLISECONDS)
     public void reentryOnHandshakeCompleteNioChannel(SslProvider clientProvider, SslProvider serverProvider)
             throws Exception {
-        EventLoopGroup group = new NioEventLoopGroup();
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         try {
             Class<? extends ServerChannel> serverClass = NioServerSocketChannel.class;
             Class<? extends Channel> clientClass = NioSocketChannel.class;
@@ -547,11 +548,12 @@ public void reentryOnHandshakeCompleteNioChannel(SslProvider clientProvider, Ssl
     @Timeout(value = 30000, unit = TimeUnit.MILLISECONDS)
     public void reentryOnHandshakeCompleteLocalChannel(SslProvider clientProvider, SslProvider serverProvider)
             throws Exception {
-        EventLoopGroup group = new DefaultEventLoopGroup();
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(LocalIoHandler.newFactory());
         try {
             Class<? extends ServerChannel> serverClass = LocalServerChannel.class;
             Class<? extends Channel> clientClass = LocalChannel.class;
-            SocketAddress bindAddress = new LocalAddress(String.valueOf(current().nextLong()));
+            SocketAddress bindAddress = new LocalAddress(String.valueOf(
+                    PlatformDependent.threadLocalRandom().nextLong()));
             reentryOnHandshakeComplete(clientProvider, serverProvider, group, bindAddress,
                     serverClass, clientClass, false, false);
             reentryOnHandshakeComplete(clientProvider, serverProvider, group, bindAddress,
diff --git a/handler/src/test/java/io/netty/handler/ssl/RenegotiateTest.java b/handler/src/test/java/io/netty/handler/ssl/RenegotiateTest.java
index 210ff4b6bb2..43007059531 100644
--- a/handler/src/test/java/io/netty/handler/ssl/RenegotiateTest.java
+++ b/handler/src/test/java/io/netty/handler/ssl/RenegotiateTest.java
@@ -22,9 +22,10 @@
 import io.netty.channel.ChannelInboundHandlerAdapter;
 import io.netty.channel.ChannelInitializer;
 import io.netty.channel.EventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
 import io.netty.channel.local.LocalAddress;
 import io.netty.channel.local.LocalChannel;
-import io.netty.channel.local.LocalEventLoopGroup;
+import io.netty.channel.local.LocalIoHandler;
 import io.netty.channel.local.LocalServerChannel;
 import io.netty.handler.ssl.util.InsecureTrustManagerFactory;
 import io.netty.handler.ssl.util.SelfSignedCertificate;
@@ -46,7 +47,7 @@ public void testRenegotiateServer() throws Throwable {
         final AtomicReference<Throwable> error = new AtomicReference<Throwable>();
         final CountDownLatch latch = new CountDownLatch(2);
         SelfSignedCertificate cert = new SelfSignedCertificate();
-        EventLoopGroup group = new LocalEventLoopGroup();
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(LocalIoHandler.newFactory());
         try {
             final SslContext context = SslContextBuilder.forServer(cert.key(), cert.cert())
                     .sslProvider(serverSslProvider())
diff --git a/handler/src/test/java/io/netty/handler/ssl/SSLEngineTest.java b/handler/src/test/java/io/netty/handler/ssl/SSLEngineTest.java
index bdc1351625e..3423d5c5de6 100644
--- a/handler/src/test/java/io/netty/handler/ssl/SSLEngineTest.java
+++ b/handler/src/test/java/io/netty/handler/ssl/SSLEngineTest.java
@@ -28,8 +28,9 @@
 import io.netty.channel.ChannelInboundHandlerAdapter;
 import io.netty.channel.ChannelInitializer;
 import io.netty.channel.ChannelPipeline;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
 import io.netty.channel.SimpleChannelInboundHandler;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.SocketChannel;
 import io.netty.channel.socket.nio.NioServerSocketChannel;
 import io.netty.channel.socket.nio.NioSocketChannel;
@@ -827,7 +828,8 @@ protected void mySetupMutualAuth(final SSLEngineTestParam param, KeyManagerFacto
         sb = new ServerBootstrap();
         cb = new Bootstrap();
 
-        sb.group(new NioEventLoopGroup(), new NioEventLoopGroup());
+        sb.group(new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory()),
+                new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory()));
         sb.channel(NioServerSocketChannel.class);
         sb.childHandler(new ChannelInitializer<Channel>() {
             @Override
@@ -872,7 +874,7 @@ public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws E
             }
         });
 
-        cb.group(new NioEventLoopGroup());
+        cb.group(new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory()));
         cb.channel(NioSocketChannel.class);
         cb.handler(new ChannelInitializer<Channel>() {
             @Override
@@ -994,7 +996,8 @@ private Future<Void> mySetupClientHostnameValidation(final SSLEngineTestParam pa
         sb = new ServerBootstrap();
         cb = new Bootstrap();
 
-        sb.group(new NioEventLoopGroup(), new NioEventLoopGroup());
+        sb.group(new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory()),
+                new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory()));
         sb.channel(NioServerSocketChannel.class);
         sb.childHandler(new ChannelInitializer<Channel>() {
             @Override
@@ -1037,7 +1040,7 @@ public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws E
         });
 
         final Promise<Void> clientWritePromise = ImmediateEventExecutor.INSTANCE.newPromise();
-        cb.group(new NioEventLoopGroup());
+        cb.group(new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory()));
         cb.channel(NioSocketChannel.class);
         cb.handler(new ChannelInitializer<Channel>() {
             @Override
@@ -1182,7 +1185,8 @@ private void mySetupMutualAuth(final SSLEngineTestParam param,
         sb = new ServerBootstrap();
         cb = new Bootstrap();
 
-        sb.group(new NioEventLoopGroup(), new NioEventLoopGroup());
+        sb.group(new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory()),
+                new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory()));
         sb.channel(NioServerSocketChannel.class);
         sb.childHandler(new ChannelInitializer<Channel>() {
             @Override
@@ -1224,7 +1228,7 @@ public void userEventTriggered(ChannelHandlerContext ctx, Object evt) throws Exc
             }
         });
 
-        cb.group(new NioEventLoopGroup());
+        cb.group(new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory()));
         cb.channel(NioSocketChannel.class);
         cb.handler(new ChannelInitializer<Channel>() {
             @Override
@@ -1469,7 +1473,7 @@ public void clientInitiatedRenegotiationWithFatalAlertDoesNotInfiniteLoopServer(
                                         .ciphers(param.ciphers())
                                         .build());
         sb = new ServerBootstrap()
-                .group(new NioEventLoopGroup(1))
+                .group(new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory()))
                 .channel(NioServerSocketChannel.class)
                 .childHandler(new ChannelInitializer<SocketChannel>() {
                     @Override
@@ -1530,7 +1534,7 @@ public void channelInactive(ChannelHandlerContext ctx) {
                                         .build());
 
         cb = new Bootstrap();
-        cb.group(new NioEventLoopGroup(1))
+        cb.group(new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory()))
                 .channel(NioSocketChannel.class)
                 .handler(new ChannelInitializer<SocketChannel>() {
                     @Override
@@ -1878,7 +1882,8 @@ protected void setupHandlers(final BufferType type, final boolean delegate,
         sb = new ServerBootstrap();
         cb = new Bootstrap();
 
-        sb.group(new NioEventLoopGroup(), new NioEventLoopGroup());
+        sb.group(new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory()),
+                new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory()));
         sb.channel(NioServerSocketChannel.class);
         sb.childHandler(new ChannelInitializer<Channel>() {
             @Override
@@ -1908,7 +1913,7 @@ public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws E
             }
         });
 
-        cb.group(new NioEventLoopGroup());
+        cb.group(new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory()));
         cb.channel(NioSocketChannel.class);
         cb.handler(new ChannelInitializer<Channel>() {
             @Override
@@ -1964,7 +1969,8 @@ public void testMutualAuthSameCertChain(final SSLEngineTestParam param) throws E
                                  .ciphers(param.ciphers()).build());
 
         sb = new ServerBootstrap();
-        sb.group(new NioEventLoopGroup(), new NioEventLoopGroup());
+        sb.group(new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory()),
+                new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory()));
         sb.channel(NioServerSocketChannel.class);
 
         final Promise<String> promise = sb.config().group().next().newPromise();
@@ -2046,7 +2052,7 @@ public void userEventTriggered(ChannelHandlerContext ctx, Object evt) throws Exc
                 .sslContextProvider(clientSslContextProvider())
                 .protocols(param.protocols()).ciphers(param.ciphers()).build());
         cb = new Bootstrap();
-        cb.group(new NioEventLoopGroup());
+        cb.group(new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory()));
         cb.channel(NioSocketChannel.class);
         clientChannel = cb.handler(new ChannelInitializer<Channel>() {
             @Override
@@ -4184,7 +4190,8 @@ public void testMasterKeyLogging(final SSLEngineTestParam param) throws Exceptio
 
         try {
             sb = new ServerBootstrap();
-            sb.group(new NioEventLoopGroup(), new NioEventLoopGroup());
+            sb.group(new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory()),
+                    new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory()));
             sb.channel(NioServerSocketChannel.class);
 
             final Promise<SecretKey> promise = sb.config().group().next().newPromise();
diff --git a/handler/src/test/java/io/netty/handler/ssl/SniHandlerTest.java b/handler/src/test/java/io/netty/handler/ssl/SniHandlerTest.java
index 25de5476228..1db6e1f807e 100644
--- a/handler/src/test/java/io/netty/handler/ssl/SniHandlerTest.java
+++ b/handler/src/test/java/io/netty/handler/ssl/SniHandlerTest.java
@@ -28,6 +28,9 @@
 import javax.net.ssl.SSLEngine;
 import javax.net.ssl.SSLException;
 
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.local.LocalIoHandler;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.handler.codec.TooLongFrameException;
 import io.netty.util.concurrent.Future;
 
@@ -42,13 +45,11 @@
 import io.netty.channel.ChannelInboundHandlerAdapter;
 import io.netty.channel.ChannelInitializer;
 import io.netty.channel.ChannelPipeline;
-import io.netty.channel.DefaultEventLoopGroup;
 import io.netty.channel.EventLoopGroup;
 import io.netty.channel.embedded.EmbeddedChannel;
 import io.netty.channel.local.LocalAddress;
 import io.netty.channel.local.LocalChannel;
 import io.netty.channel.local.LocalServerChannel;
-import io.netty.channel.nio.NioEventLoopGroup;
 import io.netty.channel.socket.nio.NioServerSocketChannel;
 import io.netty.channel.socket.nio.NioSocketChannel;
 import io.netty.handler.codec.DecoderException;
@@ -411,7 +412,7 @@ public void testSniWithApnHandler(SslProvider provider) throws Exception {
                     .add("*.netty.io", nettyContext)
                     .add("sni.fake.site", sniContext).build();
             final SniHandler handler = new SniHandler(mapping);
-            EventLoopGroup group = new NioEventLoopGroup(2);
+            EventLoopGroup group = new MultiThreadIoEventLoopGroup(2, NioIoHandler.newFactory());
             Channel serverChannel = null;
             Channel clientChannel = null;
             try {
@@ -491,7 +492,7 @@ public void testReplaceHandler(SslProvider provider) throws Exception {
             case OPENSSL_REFCNT:
                 final String sniHost = "sni.netty.io";
                 LocalAddress address = new LocalAddress("testReplaceHandler-" + Math.random());
-                EventLoopGroup group = new DefaultEventLoopGroup(1);
+                EventLoopGroup group = new MultiThreadIoEventLoopGroup(1, LocalIoHandler.newFactory());
                 Channel sc = null;
                 Channel cc = null;
                 SslContext sslContext = null;
diff --git a/handler/src/test/java/io/netty/handler/ssl/SslErrorTest.java b/handler/src/test/java/io/netty/handler/ssl/SslErrorTest.java
index be73753025e..700b9b0690c 100644
--- a/handler/src/test/java/io/netty/handler/ssl/SslErrorTest.java
+++ b/handler/src/test/java/io/netty/handler/ssl/SslErrorTest.java
@@ -22,7 +22,8 @@
 import io.netty.channel.ChannelInboundHandlerAdapter;
 import io.netty.channel.ChannelInitializer;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.nio.NioServerSocketChannel;
 import io.netty.channel.socket.nio.NioSocketChannel;
 import io.netty.handler.logging.LogLevel;
@@ -140,7 +141,7 @@ public void testCorrectAlert(SslProvider serverProvider, final SslProvider clien
 
         Channel serverChannel = null;
         Channel clientChannel = null;
-        EventLoopGroup group = new NioEventLoopGroup();
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         final Promise<Void> promise = group.next().newPromise();
         try {
             serverChannel = new ServerBootstrap().group(group)
diff --git a/handler/src/test/java/io/netty/handler/ssl/SslHandlerTest.java b/handler/src/test/java/io/netty/handler/ssl/SslHandlerTest.java
index 0025e14a130..93b9e38bd66 100644
--- a/handler/src/test/java/io/netty/handler/ssl/SslHandlerTest.java
+++ b/handler/src/test/java/io/netty/handler/ssl/SslHandlerTest.java
@@ -35,13 +35,14 @@
 import io.netty.channel.DefaultChannelId;
 import io.netty.channel.DefaultEventLoopGroup;
 import io.netty.channel.EventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
 import io.netty.channel.SimpleChannelInboundHandler;
 import io.netty.channel.embedded.EmbeddedChannel;
 import io.netty.channel.local.LocalAddress;
 import io.netty.channel.local.LocalChannel;
-import io.netty.channel.local.LocalEventLoopGroup;
+import io.netty.channel.local.LocalIoHandler;
 import io.netty.channel.local.LocalServerChannel;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.nio.NioServerSocketChannel;
 import io.netty.channel.socket.nio.NioSocketChannel;
 import io.netty.handler.codec.ByteToMessageDecoder;
@@ -476,7 +477,7 @@ public void testIssueReadAfterWriteFlushActive() throws Exception {
     @Test
     @Timeout(value = 30000, unit = TimeUnit.MILLISECONDS)
     public void testRemoval() throws Exception {
-        NioEventLoopGroup group = new NioEventLoopGroup();
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         Channel sc = null;
         Channel cc = null;
         try {
@@ -700,7 +701,7 @@ public void writingReadOnlyBufferDoesNotBreakAggregation() throws Exception {
         final SslContext sslClientCtx = SslContextBuilder.forClient()
                 .trustManager(InsecureTrustManagerFactory.INSTANCE).build();
 
-        EventLoopGroup group = new NioEventLoopGroup();
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         Channel sc = null;
         Channel cc = null;
         final CountDownLatch serverReceiveLatch = new CountDownLatch(1);
@@ -771,7 +772,7 @@ public void testCloseOnHandshakeFailure() throws Exception {
                 .trustManager(new SelfSignedCertificate().cert())
                 .build();
 
-        EventLoopGroup group = new LocalEventLoopGroup(1);
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(1, LocalIoHandler.newFactory());
         Channel sc = null;
         Channel cc = null;
         try {
@@ -845,7 +846,7 @@ public void testHandshakeFailedByWriteBeforeChannelActive() throws Exception {
                                                          .trustManager(InsecureTrustManagerFactory.INSTANCE)
                                                          .sslProvider(SslProvider.JDK).build();
 
-        EventLoopGroup group = new NioEventLoopGroup();
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         Channel sc = null;
         Channel cc = null;
         final CountDownLatch activeLatch = new CountDownLatch(1);
@@ -929,7 +930,7 @@ private static void testHandshakeTimeout0(final boolean startTls) throws Excepti
                                                          .trustManager(InsecureTrustManagerFactory.INSTANCE)
                                                          .sslProvider(SslProvider.JDK).build();
 
-        EventLoopGroup group = new NioEventLoopGroup();
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         Channel sc = null;
         Channel cc = null;
         final SslHandler sslHandler = sslClientCtx.newHandler(UnpooledByteBufAllocator.DEFAULT);
@@ -1116,7 +1117,7 @@ private static void testHandshakeWithExecutor(Executor executor, SslProvider pro
                     .sslProvider(provider).build();
         }
 
-        EventLoopGroup group = new NioEventLoopGroup();
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         Channel sc = null;
         Channel cc = null;
         final SslHandler clientSslHandler = new SslHandler(
@@ -1196,7 +1197,7 @@ private static void testHandshakeTimeoutBecauseExecutorNotExecute(final boolean
         final SslContext sslServerCtx = SslContextBuilder.forServer(cert.key(), cert.cert())
                 .sslProvider(SslProvider.JDK).build();
 
-        EventLoopGroup group = new NioEventLoopGroup();
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         Channel sc = null;
         Channel cc = null;
         final SslHandler clientSslHandler = sslClientCtx.newHandler(UnpooledByteBufAllocator.DEFAULT, new Executor() {
@@ -1316,7 +1317,7 @@ private static void testSessionTickets(SslProvider provider, String protocol, bo
             ((OpenSslSessionContext) sslServerCtx.sessionContext()).setTicketKeys();
         }
 
-        EventLoopGroup group = new NioEventLoopGroup();
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         Channel sc = null;
         final byte[] bytes = new byte[96];
         PlatformDependent.threadLocalRandom().nextBytes(bytes);
@@ -1496,7 +1497,7 @@ private void failVerification() throws CertificateException {
         final SslContext sslServerCtx = SslContextBuilder.forServer(cert.key(), cert.cert())
                 .sslProvider(SslProvider.JDK).build();
 
-        EventLoopGroup group = new NioEventLoopGroup();
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         Channel sc = null;
         final SslHandler clientSslHandler = sslClientCtx.newHandler(UnpooledByteBufAllocator.DEFAULT);
         final SslHandler serverSslHandler = sslServerCtx.newHandler(UnpooledByteBufAllocator.DEFAULT);
@@ -1610,7 +1611,7 @@ private static void testHandshakeFailureCipherMissmatch(SslProvider provider, bo
                 .ciphers(Collections.singleton(serverCipher))
                 .sslProvider(provider).build();
 
-        EventLoopGroup group = new NioEventLoopGroup();
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         Channel sc = null;
         Channel cc = null;
         final SslHandler clientSslHandler = sslClientCtx.newHandler(UnpooledByteBufAllocator.DEFAULT);
@@ -1724,7 +1725,7 @@ private void testSslCompletionEvents(SslProvider provider, final String protocol
                 .protocols(protocol)
                 .sslProvider(provider).build();
 
-        EventLoopGroup group = new NioEventLoopGroup();
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
 
         final LinkedBlockingQueue<Channel> acceptedChannels =
                 new LinkedBlockingQueue<Channel>();
diff --git a/handler/src/test/java/io/netty/handler/traffic/FileRegionThrottleTest.java b/handler/src/test/java/io/netty/handler/traffic/FileRegionThrottleTest.java
index 58481e7d555..8d4ed5c9de5 100644
--- a/handler/src/test/java/io/netty/handler/traffic/FileRegionThrottleTest.java
+++ b/handler/src/test/java/io/netty/handler/traffic/FileRegionThrottleTest.java
@@ -26,7 +26,8 @@
 import io.netty.channel.ChannelInitializer;
 import io.netty.channel.DefaultFileRegion;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.SocketChannel;
 import io.netty.channel.socket.nio.NioServerSocketChannel;
 import io.netty.channel.socket.nio.NioSocketChannel;
@@ -85,7 +86,7 @@ public static void beforeClass() throws IOException {
 
     @BeforeEach
     public void setUp() {
-        group = new NioEventLoopGroup();
+        group = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
     }
 
     @AfterEach
diff --git a/handler/src/test/java/io/netty/handler/traffic/TrafficShapingHandlerTest.java b/handler/src/test/java/io/netty/handler/traffic/TrafficShapingHandlerTest.java
index f95ad8b43e2..53de7630de7 100644
--- a/handler/src/test/java/io/netty/handler/traffic/TrafficShapingHandlerTest.java
+++ b/handler/src/test/java/io/netty/handler/traffic/TrafficShapingHandlerTest.java
@@ -26,9 +26,11 @@
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.ChannelInboundHandlerAdapter;
 import io.netty.channel.ChannelInitializer;
-import io.netty.channel.DefaultEventLoopGroup;
+import io.netty.channel.EventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
 import io.netty.channel.local.LocalAddress;
 import io.netty.channel.local.LocalChannel;
+import io.netty.channel.local.LocalIoHandler;
 import io.netty.channel.local.LocalServerChannel;
 import io.netty.util.Attribute;
 import io.netty.util.CharsetUtil;
@@ -42,7 +44,7 @@ public class TrafficShapingHandlerTest {
 
     private static final long READ_LIMIT_BYTES_PER_SECOND = 1;
     private static final ScheduledExecutorService SES = Executors.newSingleThreadScheduledExecutor();
-    private static final DefaultEventLoopGroup GROUP = new DefaultEventLoopGroup(1);
+    private static final EventLoopGroup GROUP = new MultiThreadIoEventLoopGroup(1, LocalIoHandler.newFactory());
 
     @AfterAll
     public static void destroy() {
diff --git a/microbench/src/main/java/io/netty/microbench/channel/epoll/EpollSocketChannelBenchmark.java b/microbench/src/main/java/io/netty/microbench/channel/epoll/EpollSocketChannelBenchmark.java
index 268c08ed531..343f21bd5c5 100644
--- a/microbench/src/main/java/io/netty/microbench/channel/epoll/EpollSocketChannelBenchmark.java
+++ b/microbench/src/main/java/io/netty/microbench/channel/epoll/EpollSocketChannelBenchmark.java
@@ -23,7 +23,9 @@
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.ChannelInitializer;
 import io.netty.channel.ChannelPromise;
-import io.netty.channel.epoll.EpollEventLoopGroup;
+import io.netty.channel.EventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.epoll.EpollIoHandler;
 import io.netty.channel.epoll.EpollServerSocketChannel;
 import io.netty.channel.epoll.EpollSocketChannel;
 import io.netty.microbench.util.AbstractMicrobenchmark;
@@ -41,7 +43,7 @@ public class EpollSocketChannelBenchmark extends AbstractMicrobenchmark {
         public void run() { }
     };
 
-    private EpollEventLoopGroup group;
+    private EventLoopGroup group;
     private Channel serverChan;
     private Channel chan;
     private ByteBuf abyte;
@@ -49,7 +51,7 @@ public void run() { }
 
     @Setup
     public void setup() throws Exception {
-        group = new EpollEventLoopGroup(1);
+        group = new MultiThreadIoEventLoopGroup(1, EpollIoHandler.newFactory());
 
         // add an arbitrary timeout to make the timer reschedule
         future = group.schedule(new Runnable() {
diff --git a/microbench/src/main/java/io/netty/util/concurrent/ScheduleFutureTaskBenchmark.java b/microbench/src/main/java/io/netty/util/concurrent/ScheduleFutureTaskBenchmark.java
index 2b0e7b22ca6..0d0a2684cb0 100644
--- a/microbench/src/main/java/io/netty/util/concurrent/ScheduleFutureTaskBenchmark.java
+++ b/microbench/src/main/java/io/netty/util/concurrent/ScheduleFutureTaskBenchmark.java
@@ -18,6 +18,8 @@
 import java.util.concurrent.Callable;
 import java.util.concurrent.TimeUnit;
 
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import org.openjdk.jmh.annotations.Benchmark;
 import org.openjdk.jmh.annotations.Level;
 import org.openjdk.jmh.annotations.Measurement;
@@ -29,7 +31,6 @@
 import org.openjdk.jmh.annotations.Threads;
 import org.openjdk.jmh.annotations.Warmup;
 
-import io.netty.channel.nio.NioEventLoopGroup;
 import io.netty.microbench.util.AbstractMicrobenchmark;
 
 @Warmup(iterations = 5, time = 3, timeUnit = TimeUnit.SECONDS)
@@ -54,7 +55,8 @@ public static class ThreadState {
 
         @Setup(Level.Trial)
         public void reset() {
-            eventLoop = (AbstractScheduledEventExecutor) new NioEventLoopGroup(1).next();
+            eventLoop = (AbstractScheduledEventExecutor) new MultiThreadIoEventLoopGroup(
+                    1, NioIoHandler.newFactory()).next();
         }
 
         @Setup(Level.Invocation)
diff --git a/microbench/src/main/java/io/netty/util/concurrent/ScheduledFutureTaskDeadlineBenchmark.java b/microbench/src/main/java/io/netty/util/concurrent/ScheduledFutureTaskDeadlineBenchmark.java
index bcb8ae67896..152990a4c3b 100644
--- a/microbench/src/main/java/io/netty/util/concurrent/ScheduledFutureTaskDeadlineBenchmark.java
+++ b/microbench/src/main/java/io/netty/util/concurrent/ScheduledFutureTaskDeadlineBenchmark.java
@@ -15,7 +15,8 @@
  */
 package io.netty.util.concurrent;
 
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.microbench.util.AbstractMicrobenchmark;
 import org.openjdk.jmh.annotations.Benchmark;
 import org.openjdk.jmh.annotations.Level;
@@ -41,7 +42,8 @@ public static class ThreadState {
 
         @Setup(Level.Trial)
         public void reset() {
-            eventLoop = (AbstractScheduledEventExecutor) new NioEventLoopGroup(1).next();
+            eventLoop = (AbstractScheduledEventExecutor) new MultiThreadIoEventLoopGroup(
+                    1, NioIoHandler.newFactory()).next();
             future = (ScheduledFutureTask<?>) eventLoop.schedule(new Runnable() {
                 @Override
                 public void run() {
diff --git a/resolver-dns/src/test/java/io/netty/resolver/dns/DefaultAuthoritativeDnsServerCacheTest.java b/resolver-dns/src/test/java/io/netty/resolver/dns/DefaultAuthoritativeDnsServerCacheTest.java
index 3bc95342d1a..dff90d7b0c1 100644
--- a/resolver-dns/src/test/java/io/netty/resolver/dns/DefaultAuthoritativeDnsServerCacheTest.java
+++ b/resolver-dns/src/test/java/io/netty/resolver/dns/DefaultAuthoritativeDnsServerCacheTest.java
@@ -18,7 +18,8 @@
 import io.netty.channel.DefaultEventLoopGroup;
 import io.netty.channel.EventLoop;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.local.LocalIoHandler;
 import io.netty.util.NetUtil;
 import org.junit.jupiter.api.Test;
 
@@ -74,7 +75,7 @@ public void testExpireWithDifferentTTLs() {
     }
 
     private static void testExpireWithTTL0(int days) {
-        EventLoopGroup group = new NioEventLoopGroup(1);
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(1, LocalIoHandler.newFactory());
 
         try {
             EventLoop loop = group.next();
@@ -91,7 +92,7 @@ public void testAddMultipleDnsServerForSameHostname() throws Exception {
                 InetAddress.getByAddress("ns1", new byte[] { 10, 0, 0, 1 }), 53);
         InetSocketAddress resolved2 = new InetSocketAddress(
                 InetAddress.getByAddress("ns2", new byte[] { 10, 0, 0, 2 }), 53);
-        EventLoopGroup group = new DefaultEventLoopGroup(1);
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(1, LocalIoHandler.newFactory());
 
         try {
             EventLoop loop = group.next();
@@ -115,7 +116,7 @@ public void testUnresolvedReplacedByResolved() throws Exception {
                 InetAddress.getByAddress("ns2", new byte[] { 10, 0, 0, 2 }), 53);
         InetSocketAddress resolved2 = new InetSocketAddress(
                 InetAddress.getByAddress("ns1", new byte[] { 10, 0, 0, 1 }), 53);
-        EventLoopGroup group = new DefaultEventLoopGroup(1);
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(1, LocalIoHandler.newFactory());
 
         try {
             EventLoop loop = group.next();
diff --git a/resolver-dns/src/test/java/io/netty/resolver/dns/DefaultDnsCacheTest.java b/resolver-dns/src/test/java/io/netty/resolver/dns/DefaultDnsCacheTest.java
index 71f5328a3f2..39e54781ddb 100644
--- a/resolver-dns/src/test/java/io/netty/resolver/dns/DefaultDnsCacheTest.java
+++ b/resolver-dns/src/test/java/io/netty/resolver/dns/DefaultDnsCacheTest.java
@@ -15,11 +15,10 @@
  */
 package io.netty.resolver.dns;
 
-import io.netty.channel.DefaultEventLoopGroup;
 import io.netty.channel.EventLoop;
 import io.netty.channel.EventLoopGroup;
-
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.util.NetUtil;
 import org.junit.jupiter.api.Test;
 
@@ -46,7 +45,7 @@ public class DefaultDnsCacheTest {
     public void testExpire() throws Throwable {
         InetAddress addr1 = InetAddress.getByAddress(new byte[] { 10, 0, 0, 1 });
         InetAddress addr2 = InetAddress.getByAddress(new byte[] { 10, 0, 0, 2 });
-        EventLoopGroup group = new DefaultEventLoopGroup(1);
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory());
 
         try {
             EventLoop loop = group.next();
@@ -81,7 +80,7 @@ public void testExpireWithDifferentTTLs() {
     }
 
     private static void testExpireWithTTL0(int days) {
-        EventLoopGroup group = new NioEventLoopGroup(1);
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory());
 
         try {
             EventLoop loop = group.next();
@@ -94,7 +93,7 @@ private static void testExpireWithTTL0(int days) {
 
     @Test
     public void testExpireWithToBigMinTTL() {
-        EventLoopGroup group = new NioEventLoopGroup(1);
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory());
 
         try {
             EventLoop loop = group.next();
@@ -109,7 +108,7 @@ public void testExpireWithToBigMinTTL() {
     public void testAddMultipleAddressesForSameHostname() throws Exception {
         InetAddress addr1 = InetAddress.getByAddress(new byte[] { 10, 0, 0, 1 });
         InetAddress addr2 = InetAddress.getByAddress(new byte[] { 10, 0, 0, 2 });
-        EventLoopGroup group = new DefaultEventLoopGroup(1);
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory());
 
         try {
             EventLoop loop = group.next();
@@ -129,7 +128,7 @@ public void testAddMultipleAddressesForSameHostname() throws Exception {
     @Test
     public void testAddSameAddressForSameHostname() throws Exception {
         InetAddress addr1 = InetAddress.getByAddress(new byte[] { 10, 0, 0, 1 });
-        EventLoopGroup group = new DefaultEventLoopGroup(1);
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory());
 
         try {
             EventLoop loop = group.next();
@@ -154,7 +153,7 @@ private static void assertEntry(DnsCacheEntry entry, InetAddress address) {
     public void testCacheFailed() throws Exception {
         InetAddress addr1 = InetAddress.getByAddress(new byte[] { 10, 0, 0, 1 });
         InetAddress addr2 = InetAddress.getByAddress(new byte[] { 10, 0, 0, 2 });
-        EventLoopGroup group = new DefaultEventLoopGroup(1);
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory());
 
         try {
             EventLoop loop = group.next();
@@ -183,7 +182,7 @@ public void testCacheFailed() throws Exception {
     public void testDotHandling() throws Exception {
         InetAddress addr1 = InetAddress.getByAddress(new byte[] { 10, 0, 0, 1 });
         InetAddress addr2 = InetAddress.getByAddress(new byte[] { 10, 0, 0, 2 });
-        EventLoopGroup group = new DefaultEventLoopGroup(1);
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory());
 
         try {
             EventLoop loop = group.next();
@@ -207,7 +206,7 @@ public void testDotHandling() throws Exception {
 
     @Test
     public void testCacheExceptionIsSafe() throws Exception {
-        EventLoopGroup group = new DefaultEventLoopGroup(1);
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory());
 
         try {
             EventLoop loop = group.next();
diff --git a/resolver-dns/src/test/java/io/netty/resolver/dns/DnsAddressResolverGroupTest.java b/resolver-dns/src/test/java/io/netty/resolver/dns/DnsAddressResolverGroupTest.java
index 758bfcc7f77..ec7da5b4a53 100644
--- a/resolver-dns/src/test/java/io/netty/resolver/dns/DnsAddressResolverGroupTest.java
+++ b/resolver-dns/src/test/java/io/netty/resolver/dns/DnsAddressResolverGroupTest.java
@@ -17,7 +17,9 @@
 
 import io.netty.channel.DefaultEventLoopGroup;
 import io.netty.channel.EventLoop;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.EventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.nio.NioDatagramChannel;
 import io.netty.resolver.AddressResolver;
 import io.netty.util.concurrent.Future;
@@ -35,7 +37,7 @@
 public class DnsAddressResolverGroupTest {
     @Test
     public void testUseConfiguredEventLoop() throws InterruptedException {
-        NioEventLoopGroup group = new NioEventLoopGroup(1);
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory());
         final EventLoop loop = group.next();
         DefaultEventLoopGroup defaultEventLoopGroup = new DefaultEventLoopGroup(1);
         DnsNameResolverBuilder builder = new DnsNameResolverBuilder()
diff --git a/resolver-dns/src/test/java/io/netty/resolver/dns/DnsNameResolverBuilderTest.java b/resolver-dns/src/test/java/io/netty/resolver/dns/DnsNameResolverBuilderTest.java
index e62c69767ec..f8c90e3a364 100644
--- a/resolver-dns/src/test/java/io/netty/resolver/dns/DnsNameResolverBuilderTest.java
+++ b/resolver-dns/src/test/java/io/netty/resolver/dns/DnsNameResolverBuilderTest.java
@@ -17,7 +17,8 @@
 
 import io.netty.channel.EventLoop;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.nio.NioDatagramChannel;
 import io.netty.handler.codec.dns.DnsRecord;
 import org.junit.jupiter.api.AfterAll;
@@ -33,7 +34,7 @@
 import static org.assertj.core.api.Assertions.assertThat;
 
 class DnsNameResolverBuilderTest {
-    private static final EventLoopGroup GROUP = new NioEventLoopGroup(1);
+    private static final EventLoopGroup GROUP = new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory());
 
     private DnsNameResolverBuilder builder;
     private DnsNameResolver resolver;
diff --git a/resolver-dns/src/test/java/io/netty/resolver/dns/DnsNameResolverClientSubnetTest.java b/resolver-dns/src/test/java/io/netty/resolver/dns/DnsNameResolverClientSubnetTest.java
index f707e6fcbb7..3353139be00 100644
--- a/resolver-dns/src/test/java/io/netty/resolver/dns/DnsNameResolverClientSubnetTest.java
+++ b/resolver-dns/src/test/java/io/netty/resolver/dns/DnsNameResolverClientSubnetTest.java
@@ -16,7 +16,8 @@
 package io.netty.resolver.dns;
 
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.nio.NioDatagramChannel;
 import io.netty.handler.codec.dns.DefaultDnsOptEcsRecord;
 import io.netty.handler.codec.dns.DnsRecord;
@@ -37,7 +38,7 @@ public class DnsNameResolverClientSubnetTest {
     @Disabled
     @Test
     public void testSubnetQuery() throws Exception {
-        EventLoopGroup group = new NioEventLoopGroup(1);
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory());
         DnsNameResolver resolver = newResolver(group).build();
         try {
             // Same as:
diff --git a/resolver-dns/src/test/java/io/netty/resolver/dns/DnsNameResolverTest.java b/resolver-dns/src/test/java/io/netty/resolver/dns/DnsNameResolverTest.java
index d2eb64b80b8..21825f2e2c2 100644
--- a/resolver-dns/src/test/java/io/netty/resolver/dns/DnsNameResolverTest.java
+++ b/resolver-dns/src/test/java/io/netty/resolver/dns/DnsNameResolverTest.java
@@ -24,8 +24,9 @@
 import io.netty.channel.ChannelInboundHandlerAdapter;
 import io.netty.channel.EventLoop;
 import io.netty.channel.EventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
 import io.netty.channel.ReflectiveChannelFactory;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.DatagramChannel;
 import io.netty.channel.socket.DatagramPacket;
 import io.netty.channel.socket.InternetProtocolFamily;
@@ -378,7 +379,7 @@ public class DnsNameResolverTest {
     }
 
     private static final TestDnsServer dnsServer = new TestDnsServer(DOMAINS_ALL);
-    private static final EventLoopGroup group = new NioEventLoopGroup(1);
+    private static final EventLoopGroup group = new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory());
 
     private static DnsNameResolverBuilder newResolver(boolean decodeToUnicode) {
         return newResolver(decodeToUnicode, null);
@@ -1408,7 +1409,7 @@ private static void testRecursiveResolveCache(boolean cache)
                 cache ? new DefaultAuthoritativeDnsServerCache() : NoopAuthoritativeDnsServerCache.INSTANCE);
         TestRecursiveCacheDnsQueryLifecycleObserverFactory lifecycleObserverFactory =
                 new TestRecursiveCacheDnsQueryLifecycleObserverFactory();
-        EventLoopGroup group = new NioEventLoopGroup(1);
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory());
         final DnsNameResolver resolver = new DnsNameResolver(
                 group.next(), new ReflectiveChannelFactory<DatagramChannel>(NioDatagramChannel.class),
                 NoopDnsCache.INSTANCE, nsCache, lifecycleObserverFactory, 3000, ResolvedAddressTypes.IPV4_ONLY, true,
@@ -1566,7 +1567,7 @@ protected DnsMessage filterMessage(DnsMessage message) {
             }
         };
         redirectServer.start();
-        EventLoopGroup group = new NioEventLoopGroup(1);
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory());
         final DnsNameResolver resolver = new DnsNameResolver(
                 group.next(), new ReflectiveChannelFactory<DatagramChannel>(NioDatagramChannel.class),
                 cache, authoritativeDnsServerCache, NoopDnsQueryLifecycleObserverFactory.INSTANCE, 2000,
@@ -1702,7 +1703,7 @@ private ResourceRecord newARecord(InetSocketAddress address) {
             }
         };
         redirectServer.start();
-        EventLoopGroup group = new NioEventLoopGroup(1);
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory());
 
         final List<InetSocketAddress> cached = new CopyOnWriteArrayList<InetSocketAddress>();
         final AuthoritativeDnsServerCache authoritativeDnsServerCache = new AuthoritativeDnsServerCache() {
@@ -1832,7 +1833,7 @@ private ResourceRecord newARecord(InetSocketAddress address) {
             }
         };
         redirectServer.start();
-        EventLoopGroup group = new NioEventLoopGroup(1);
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory());
 
         final List<InetSocketAddress> cached = new CopyOnWriteArrayList<InetSocketAddress>();
         final AuthoritativeDnsServerCache authoritativeDnsServerCache = new AuthoritativeDnsServerCache() {
@@ -4222,7 +4223,7 @@ protected DnsMessage filterMessage(DnsMessage message) {
             }
         };
         server.start();
-        EventLoopGroup group = new NioEventLoopGroup(1);
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory());
 
         final DnsNameResolver resolver = new DnsNameResolver(
                 group.next(), new ReflectiveChannelFactory<DatagramChannel>(NioDatagramChannel.class),
diff --git a/resolver-dns/src/test/java/io/netty/resolver/dns/SearchDomainTest.java b/resolver-dns/src/test/java/io/netty/resolver/dns/SearchDomainTest.java
index 98b0a689ec6..f87a7252498 100644
--- a/resolver-dns/src/test/java/io/netty/resolver/dns/SearchDomainTest.java
+++ b/resolver-dns/src/test/java/io/netty/resolver/dns/SearchDomainTest.java
@@ -16,7 +16,8 @@
 package io.netty.resolver.dns;
 
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.nio.NioDatagramChannel;
 import io.netty.util.concurrent.Future;
 import org.junit.jupiter.api.AfterEach;
@@ -58,7 +59,7 @@ private DnsNameResolverBuilder newResolver() {
 
     @BeforeEach
     public void before() {
-        group = new NioEventLoopGroup(1);
+        group = new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory());
     }
 
     @AfterEach
diff --git a/testsuite-autobahn/src/main/java/io/netty/testsuite/autobahn/AutobahnServer.java b/testsuite-autobahn/src/main/java/io/netty/testsuite/autobahn/AutobahnServer.java
index 02fbc9b7ea8..52ae74ac10e 100644
--- a/testsuite-autobahn/src/main/java/io/netty/testsuite/autobahn/AutobahnServer.java
+++ b/testsuite-autobahn/src/main/java/io/netty/testsuite/autobahn/AutobahnServer.java
@@ -20,7 +20,8 @@
 import io.netty.channel.ChannelFuture;
 import io.netty.channel.ChannelOption;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.nio.NioServerSocketChannel;
 
 /**
@@ -36,8 +37,8 @@ public AutobahnServer(int port) {
     }
 
     public void run() throws Exception {
-        EventLoopGroup bossGroup = new NioEventLoopGroup(1);
-        EventLoopGroup workerGroup = new NioEventLoopGroup();
+        EventLoopGroup bossGroup = new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory());
+        EventLoopGroup workerGroup = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         try {
             ServerBootstrap b = new ServerBootstrap();
             b.group(bossGroup, workerGroup)
diff --git a/testsuite-http2/src/main/java/io/netty/testsuite/http2/Http2Server.java b/testsuite-http2/src/main/java/io/netty/testsuite/http2/Http2Server.java
index eb8b3b27d23..89da3fbf909 100644
--- a/testsuite-http2/src/main/java/io/netty/testsuite/http2/Http2Server.java
+++ b/testsuite-http2/src/main/java/io/netty/testsuite/http2/Http2Server.java
@@ -20,7 +20,8 @@
 import io.netty.channel.Channel;
 import io.netty.channel.ChannelOption;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.nio.NioServerSocketChannel;
 import io.netty.handler.logging.LogLevel;
 import io.netty.handler.logging.LoggingHandler;
@@ -39,7 +40,7 @@ public final class Http2Server {
 
     void run() throws Exception {
         // Configure the server.
-        EventLoopGroup group = new NioEventLoopGroup();
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         try {
             ServerBootstrap b = new ServerBootstrap();
             b.option(ChannelOption.SO_BACKLOG, 1024);
diff --git a/testsuite-native-image-client/src/main/java/io/netty/testsuite/svm/client/DnsNativeClient.java b/testsuite-native-image-client/src/main/java/io/netty/testsuite/svm/client/DnsNativeClient.java
index afbbd61eb14..a1d7a4a4205 100644
--- a/testsuite-native-image-client/src/main/java/io/netty/testsuite/svm/client/DnsNativeClient.java
+++ b/testsuite-native-image-client/src/main/java/io/netty/testsuite/svm/client/DnsNativeClient.java
@@ -15,7 +15,9 @@
  */
 package io.netty.testsuite.svm.client;
 
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.EventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.nio.NioDatagramChannel;
 import io.netty.resolver.AddressResolver;
 import io.netty.resolver.dns.DnsAddressResolverGroup;
@@ -35,7 +37,8 @@ private DnsNativeClient() {
     }
 
     public static void main(String[] args) throws Exception {
-        NioEventLoopGroup group = new NioEventLoopGroup(1, new DefaultThreadFactory("netty"));
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(
+                1, new DefaultThreadFactory("netty"), NioIoHandler.newFactory());
 
         DnsAddressResolverGroup resolverGroup = new DnsAddressResolverGroup(NioDatagramChannel.class,
                 DnsServerAddressStreamProviders.platformDefault());
diff --git a/testsuite-native-image/src/main/java/io/netty/testsuite/svm/HttpNativeServer.java b/testsuite-native-image/src/main/java/io/netty/testsuite/svm/HttpNativeServer.java
index 8b3b16eec21..9a1c412aebb 100644
--- a/testsuite-native-image/src/main/java/io/netty/testsuite/svm/HttpNativeServer.java
+++ b/testsuite-native-image/src/main/java/io/netty/testsuite/svm/HttpNativeServer.java
@@ -19,7 +19,8 @@
 import io.netty.channel.Channel;
 import io.netty.channel.ChannelOption;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.nio.NioServerSocketChannel;
 import io.netty.handler.logging.LogLevel;
 import io.netty.handler.logging.LoggingHandler;
@@ -38,8 +39,8 @@ private HttpNativeServer() {
 
     public static void main(String[] args) throws Exception {
         // Configure the server.
-        EventLoopGroup bossGroup = new NioEventLoopGroup(1);
-        EventLoopGroup workerGroup = new NioEventLoopGroup();
+        EventLoopGroup bossGroup = new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory());
+        EventLoopGroup workerGroup = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         // Control status.
         boolean serverStartSucess = false;
         try {
diff --git a/testsuite/src/main/java/io/netty/testsuite/transport/sctp/SctpTestPermutation.java b/testsuite/src/main/java/io/netty/testsuite/transport/sctp/SctpTestPermutation.java
index 7fb3508eddb..189e981c90a 100644
--- a/testsuite/src/main/java/io/netty/testsuite/transport/sctp/SctpTestPermutation.java
+++ b/testsuite/src/main/java/io/netty/testsuite/transport/sctp/SctpTestPermutation.java
@@ -18,7 +18,8 @@
 import io.netty.bootstrap.Bootstrap;
 import io.netty.bootstrap.ServerBootstrap;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.oio.OioEventLoopGroup;
 import io.netty.channel.sctp.nio.NioSctpChannel;
 import io.netty.channel.sctp.nio.NioSctpServerChannel;
@@ -37,10 +38,10 @@ public final class SctpTestPermutation {
 
     private static final int BOSSES = 2;
     private static final int WORKERS = 3;
-    private static final EventLoopGroup nioBossGroup =
-            new NioEventLoopGroup(BOSSES, new DefaultThreadFactory("testsuite-sctp-nio-boss", true));
-    private static final EventLoopGroup nioWorkerGroup =
-            new NioEventLoopGroup(WORKERS, new DefaultThreadFactory("testsuite-sctp-nio-worker", true));
+    private static final EventLoopGroup nioBossGroup = new MultiThreadIoEventLoopGroup(
+            BOSSES, new DefaultThreadFactory("testsuite-sctp-nio-boss", true), NioIoHandler.newFactory());
+    private static final EventLoopGroup nioWorkerGroup = new MultiThreadIoEventLoopGroup(
+            WORKERS, new DefaultThreadFactory("testsuite-sctp-nio-worker", true), NioIoHandler.newFactory());
     private static final EventLoopGroup oioBossGroup =
             new OioEventLoopGroup(Integer.MAX_VALUE, new DefaultThreadFactory("testsuite-sctp-oio-boss", true));
     private static final EventLoopGroup oioWorkerGroup =
diff --git a/testsuite/src/main/java/io/netty/testsuite/transport/socket/SocketChannelNotYetConnectedTest.java b/testsuite/src/main/java/io/netty/testsuite/transport/socket/SocketChannelNotYetConnectedTest.java
index 13171a83dfb..7eeeee434e6 100644
--- a/testsuite/src/main/java/io/netty/testsuite/transport/socket/SocketChannelNotYetConnectedTest.java
+++ b/testsuite/src/main/java/io/netty/testsuite/transport/socket/SocketChannelNotYetConnectedTest.java
@@ -22,7 +22,9 @@
 import io.netty.channel.Channel;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.ChannelInboundHandlerAdapter;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.EventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.SocketChannel;
 import io.netty.channel.socket.nio.NioServerSocketChannel;
 import io.netty.handler.codec.ByteToMessageDecoder;
@@ -86,7 +88,7 @@ public void readMustBePendingUntilChannelIsActive(TestInfo info) throws Throwabl
         run(info, new Runner<Bootstrap>() {
             @Override
             public void run(Bootstrap bootstrap) throws Throwable {
-                NioEventLoopGroup group = new NioEventLoopGroup(1);
+                EventLoopGroup group = new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory());
                 ServerBootstrap sb = new ServerBootstrap().group(group);
                 Channel serverChannel = sb.childHandler(new ChannelInboundHandlerAdapter() {
                     @Override
diff --git a/testsuite/src/main/java/io/netty/testsuite/transport/socket/SocketMultipleConnectTest.java b/testsuite/src/main/java/io/netty/testsuite/transport/socket/SocketMultipleConnectTest.java
index 3019e6bca14..2224a259b46 100644
--- a/testsuite/src/main/java/io/netty/testsuite/transport/socket/SocketMultipleConnectTest.java
+++ b/testsuite/src/main/java/io/netty/testsuite/transport/socket/SocketMultipleConnectTest.java
@@ -20,7 +20,9 @@
 import io.netty.channel.Channel;
 import io.netty.channel.ChannelFuture;
 import io.netty.channel.ChannelInboundHandlerAdapter;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.EventLoopGroup;
+import io.netty.channel.IoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.testsuite.transport.TestsuitePermutation;
 import io.netty.util.NetUtil;
 import org.junit.jupiter.api.Test;
@@ -75,7 +77,8 @@ protected List<TestsuitePermutation.BootstrapComboFactory<ServerBootstrap, Boots
                 = new ArrayList<TestsuitePermutation.BootstrapComboFactory<ServerBootstrap, Bootstrap>>();
         for (TestsuitePermutation.BootstrapComboFactory<ServerBootstrap, Bootstrap> comboFactory
                 : SocketTestPermutation.INSTANCE.socketWithFastOpen()) {
-            if (comboFactory.newClientInstance().config().group() instanceof NioEventLoopGroup) {
+            EventLoopGroup group = comboFactory.newClientInstance().config().group();
+            if (group instanceof IoEventLoopGroup && ((IoEventLoopGroup) group).isIoType(NioIoHandler.class)) {
                 factories.add(comboFactory);
             }
         }
diff --git a/testsuite/src/main/java/io/netty/testsuite/transport/socket/SocketTestPermutation.java b/testsuite/src/main/java/io/netty/testsuite/transport/socket/SocketTestPermutation.java
index cace51b2ec5..4050608fdd2 100644
--- a/testsuite/src/main/java/io/netty/testsuite/transport/socket/SocketTestPermutation.java
+++ b/testsuite/src/main/java/io/netty/testsuite/transport/socket/SocketTestPermutation.java
@@ -22,7 +22,8 @@
 import io.netty.channel.ChannelFactory;
 import io.netty.channel.ChannelOption;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.oio.OioEventLoopGroup;
 import io.netty.channel.socket.InternetProtocolFamily;
 import io.netty.channel.socket.nio.NioDatagramChannel;
@@ -60,10 +61,10 @@ public class SocketTestPermutation {
 
     protected static final int OIO_SO_TIMEOUT = 10;  // Use short timeout for faster runs.
 
-    protected final EventLoopGroup nioBossGroup =
-            new NioEventLoopGroup(BOSSES, new DefaultThreadFactory("testsuite-nio-boss", true));
-    protected final EventLoopGroup nioWorkerGroup =
-            new NioEventLoopGroup(WORKERS, new DefaultThreadFactory("testsuite-nio-worker", true));
+    protected final EventLoopGroup nioBossGroup = new MultiThreadIoEventLoopGroup(
+            BOSSES, new DefaultThreadFactory("testsuite-nio-boss", true), NioIoHandler.newFactory());
+    protected final EventLoopGroup nioWorkerGroup = new MultiThreadIoEventLoopGroup(
+            WORKERS, new DefaultThreadFactory("testsuite-nio-worker", true), NioIoHandler.newFactory());
     protected final EventLoopGroup oioBossGroup =
             new OioEventLoopGroup(Integer.MAX_VALUE, new DefaultThreadFactory("testsuite-oio-boss", true));
     protected final EventLoopGroup oioWorkerGroup =
diff --git a/testsuite/src/main/java/io/netty/testsuite/transport/udt/UDTClientServerConnectionTest.java b/testsuite/src/main/java/io/netty/testsuite/transport/udt/UDTClientServerConnectionTest.java
index 75e34213bf4..598257ee2d0 100644
--- a/testsuite/src/main/java/io/netty/testsuite/transport/udt/UDTClientServerConnectionTest.java
+++ b/testsuite/src/main/java/io/netty/testsuite/transport/udt/UDTClientServerConnectionTest.java
@@ -21,10 +21,12 @@
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.ChannelInitializer;
 import io.netty.channel.ChannelPipeline;
+import io.netty.channel.EventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
 import io.netty.channel.SimpleChannelInboundHandler;
 import io.netty.channel.group.ChannelGroup;
 import io.netty.channel.group.DefaultChannelGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.udt.UdtChannel;
 import io.netty.channel.udt.nio.NioUdtProvider;
 import io.netty.handler.codec.DelimiterBasedFrameDecoder;
@@ -72,8 +74,8 @@ static class Client implements Runnable {
         public void run() {
             final Bootstrap boot = new Bootstrap();
             final ThreadFactory clientFactory = new DefaultThreadFactory("client");
-            final NioEventLoopGroup connectGroup = new NioEventLoopGroup(1,
-                    clientFactory, NioUdtProvider.BYTE_PROVIDER);
+            final EventLoopGroup connectGroup = new MultiThreadIoEventLoopGroup(1,
+                    clientFactory, NioIoHandler.newFactory(NioUdtProvider.BYTE_PROVIDER));
             try {
                 boot.group(connectGroup)
                         .channelFactory(NioUdtProvider.BYTE_CONNECTOR)
@@ -198,10 +200,10 @@ public void run() {
             final ServerBootstrap boot = new ServerBootstrap();
             final ThreadFactory acceptFactory = new DefaultThreadFactory("accept");
             final ThreadFactory serverFactory = new DefaultThreadFactory("server");
-            final NioEventLoopGroup acceptGroup = new NioEventLoopGroup(1,
-                    acceptFactory, NioUdtProvider.BYTE_PROVIDER);
-            final NioEventLoopGroup connectGroup = new NioEventLoopGroup(1,
-                    serverFactory, NioUdtProvider.BYTE_PROVIDER);
+            final EventLoopGroup acceptGroup = new MultiThreadIoEventLoopGroup(1,
+                    acceptFactory, NioIoHandler.newFactory(NioUdtProvider.BYTE_PROVIDER));
+            final EventLoopGroup connectGroup = new MultiThreadIoEventLoopGroup(1,
+                    serverFactory, NioIoHandler.newFactory(NioUdtProvider.BYTE_PROVIDER));
             try {
                 boot.group(acceptGroup, connectGroup)
                         .channelFactory(NioUdtProvider.BYTE_ACCEPTOR)
diff --git a/transport-blockhound-tests/src/test/java/io/netty/util/internal/NettyBlockHoundIntegrationTest.java b/transport-blockhound-tests/src/test/java/io/netty/util/internal/NettyBlockHoundIntegrationTest.java
index a005095d821..e51864e1409 100644
--- a/transport-blockhound-tests/src/test/java/io/netty/util/internal/NettyBlockHoundIntegrationTest.java
+++ b/transport-blockhound-tests/src/test/java/io/netty/util/internal/NettyBlockHoundIntegrationTest.java
@@ -27,7 +27,8 @@
 import io.netty.channel.ChannelInboundHandlerAdapter;
 import io.netty.channel.ChannelInitializer;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.nio.NioDatagramChannel;
 import io.netty.channel.socket.nio.NioServerSocketChannel;
 import io.netty.channel.socket.nio.NioSocketChannel;
@@ -301,7 +302,7 @@ public void testSslHandlerWrapAllowsBlockingCalls() throws Exception {
                                  .sslProvider(SslProvider.JDK)
                                  .build();
         final SslHandler sslHandler = sslClientCtx.newHandler(UnpooledByteBufAllocator.DEFAULT);
-        final EventLoopGroup group = new NioEventLoopGroup();
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         final CountDownLatch activeLatch = new CountDownLatch(1);
         final AtomicReference<Throwable> error = new AtomicReference<>();
 
@@ -410,7 +411,7 @@ public void testHostsFileParser_Parse() throws InterruptedException {
     @Timeout(value = 5000, unit = TimeUnit.MILLISECONDS)
     public void testUnixResolverDnsServerAddressStreamProvider_ParseEtcResolverSearchDomainsAndOptions()
             throws InterruptedException {
-        NioEventLoopGroup group = new NioEventLoopGroup();
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         try {
             DnsNameResolverBuilder builder = new DnsNameResolverBuilder(group.next())
                     .channelFactory(NioDatagramChannel::new);
@@ -496,7 +497,7 @@ private static void testHandshakeWithExecutor(Executor executor, String tlsVersi
 
     private static void testHandshake(SslContext sslClientCtx, SslHandler clientSslHandler,
                                       SslHandler serverSslHandler) throws Exception {
-        EventLoopGroup group = new NioEventLoopGroup();
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         Channel sc = null;
         Channel cc = null;
         try {
diff --git a/transport-native-epoll/src/test/java/io/netty/channel/epoll/EpollDatagramUnicastTest.java b/transport-native-epoll/src/test/java/io/netty/channel/epoll/EpollDatagramUnicastTest.java
index ba1970f9512..f10bc5226ef 100644
--- a/transport-native-epoll/src/test/java/io/netty/channel/epoll/EpollDatagramUnicastTest.java
+++ b/transport-native-epoll/src/test/java/io/netty/channel/epoll/EpollDatagramUnicastTest.java
@@ -23,6 +23,7 @@
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.ChannelOption;
 import io.netty.channel.FixedRecvByteBufAllocator;
+import io.netty.channel.IoEventLoopGroup;
 import io.netty.channel.SimpleChannelInboundHandler;
 import io.netty.channel.socket.DatagramPacket;
 import io.netty.channel.socket.InternetProtocolFamily;
@@ -112,11 +113,14 @@ public void testSendAndReceiveSegmentedDatagramPacketComposite(Bootstrap sb, Boo
 
     private void testSegmentedDatagramPacket(Bootstrap sb, Bootstrap cb, boolean composite, boolean gro)
             throws Throwable {
-        if (!(cb.group() instanceof EpollEventLoopGroup)) {
+        if (!(cb.group() instanceof IoEventLoopGroup &&
+                ((IoEventLoopGroup) cb.group()).isIoType(EpollIoHandler.class))) {
             // Only supported for the native epoll transport.
             return;
         }
-        if (gro && !(sb.group() instanceof EpollEventLoopGroup)) {
+
+        if (gro && !(sb.group() instanceof IoEventLoopGroup) &&
+                ((IoEventLoopGroup) sb.group()).isIoType(EpollIoHandler.class)) {
             // Only supported for the native epoll transport.
             return;
         }
diff --git a/transport-native-epoll/src/test/java/io/netty/channel/epoll/EpollSocketMultipleConnectTest.java b/transport-native-epoll/src/test/java/io/netty/channel/epoll/EpollSocketMultipleConnectTest.java
index b70313545ed..bdc9ae4e4c0 100644
--- a/transport-native-epoll/src/test/java/io/netty/channel/epoll/EpollSocketMultipleConnectTest.java
+++ b/transport-native-epoll/src/test/java/io/netty/channel/epoll/EpollSocketMultipleConnectTest.java
@@ -18,7 +18,8 @@
 import io.netty.bootstrap.Bootstrap;
 import io.netty.bootstrap.ServerBootstrap;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.IoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.testsuite.transport.TestsuitePermutation;
 import io.netty.testsuite.transport.socket.SocketMultipleConnectTest;
 
@@ -34,9 +35,15 @@ protected List<TestsuitePermutation.BootstrapComboFactory<ServerBootstrap, Boots
         for (TestsuitePermutation.BootstrapComboFactory<ServerBootstrap, Bootstrap> comboFactory
                 : EpollSocketTestPermutation.INSTANCE.socketWithFastOpen()) {
             EventLoopGroup group = comboFactory.newClientInstance().config().group();
-            if (group instanceof NioEventLoopGroup || group instanceof EpollEventLoopGroup) {
+            if (group instanceof IoEventLoopGroup && ((IoEventLoopGroup) group).isIoType(NioIoHandler.class)) {
                 factories.add(comboFactory);
             }
+            if (group instanceof IoEventLoopGroup) {
+                IoEventLoopGroup ioGroup = (IoEventLoopGroup) group;
+                if (ioGroup.isIoType(NioIoHandler.class) || ioGroup.isIoType(EpollIoHandler.class)) {
+                    factories.add(comboFactory);
+                }
+            }
         }
         return factories;
     }
diff --git a/transport-native-kqueue/src/test/java/io/netty/channel/kqueue/KQueueSocketMultipleConnectTest.java b/transport-native-kqueue/src/test/java/io/netty/channel/kqueue/KQueueSocketMultipleConnectTest.java
index dfad86ba862..f4397fc5aac 100644
--- a/transport-native-kqueue/src/test/java/io/netty/channel/kqueue/KQueueSocketMultipleConnectTest.java
+++ b/transport-native-kqueue/src/test/java/io/netty/channel/kqueue/KQueueSocketMultipleConnectTest.java
@@ -18,7 +18,8 @@
 import io.netty.bootstrap.Bootstrap;
 import io.netty.bootstrap.ServerBootstrap;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.IoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.testsuite.transport.TestsuitePermutation;
 import io.netty.testsuite.transport.socket.SocketMultipleConnectTest;
 
@@ -33,8 +34,11 @@ protected List<TestsuitePermutation.BootstrapComboFactory<ServerBootstrap, Boots
         for (TestsuitePermutation.BootstrapComboFactory<ServerBootstrap, Bootstrap> comboFactory
                 : KQueueSocketTestPermutation.INSTANCE.socket()) {
             EventLoopGroup group = comboFactory.newClientInstance().config().group();
-            if (group instanceof NioEventLoopGroup || group instanceof KQueueEventLoopGroup) {
-                factories.add(comboFactory);
+            if (group instanceof IoEventLoopGroup) {
+                IoEventLoopGroup ioGroup = (IoEventLoopGroup) group;
+                if (ioGroup.isIoType(NioIoHandler.class) || ioGroup.isIoType(KQueueIoHandler.class)) {
+                    factories.add(comboFactory);
+                }
             }
         }
         return factories;
diff --git a/transport-sctp/src/test/java/io/netty/channel/sctp/nio/NioSctpLimitStreamsTest.java b/transport-sctp/src/test/java/io/netty/channel/sctp/nio/NioSctpLimitStreamsTest.java
index 2eb1892a543..7b60eda6f58 100644
--- a/transport-sctp/src/test/java/io/netty/channel/sctp/nio/NioSctpLimitStreamsTest.java
+++ b/transport-sctp/src/test/java/io/netty/channel/sctp/nio/NioSctpLimitStreamsTest.java
@@ -16,7 +16,8 @@
 package io.netty.channel.sctp.nio;
 
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.sctp.SctpChannel;
 import io.netty.channel.sctp.SctpLimitStreamsTest;
 import io.netty.channel.sctp.SctpServerChannel;
@@ -24,7 +25,7 @@
 public class NioSctpLimitStreamsTest extends SctpLimitStreamsTest {
     @Override
     protected EventLoopGroup newEventLoopGroup() {
-        return new NioEventLoopGroup();
+        return new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
     }
 
     @Override
diff --git a/transport-udt/src/test/java/io/netty/test/udt/bench/xfer/UdtNetty.java b/transport-udt/src/test/java/io/netty/test/udt/bench/xfer/UdtNetty.java
index 36cdbd68906..69889562061 100644
--- a/transport-udt/src/test/java/io/netty/test/udt/bench/xfer/UdtNetty.java
+++ b/transport-udt/src/test/java/io/netty/test/udt/bench/xfer/UdtNetty.java
@@ -22,7 +22,9 @@
 import io.netty.bootstrap.Bootstrap;
 import io.netty.channel.ChannelFuture;
 import io.netty.channel.ChannelHandler;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.EventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.udt.nio.NioUdtProvider;
 import io.netty.test.udt.util.CustomReporter;
 import io.netty.test.udt.util.EchoMessageHandler;
@@ -92,10 +94,10 @@ public static void main(final String[] args) throws Exception {
         final ChannelHandler handler1 = new EchoMessageHandler(rate, size);
         final ChannelHandler handler2 = new EchoMessageHandler(null, size);
 
-        final NioEventLoopGroup group1 = new NioEventLoopGroup(
-                1, Executors.defaultThreadFactory(), NioUdtProvider.MESSAGE_PROVIDER);
-        final NioEventLoopGroup group2 = new NioEventLoopGroup(
-                1, Executors.defaultThreadFactory(), NioUdtProvider.MESSAGE_PROVIDER);
+        final EventLoopGroup group1 = new MultiThreadIoEventLoopGroup(
+                1, Executors.defaultThreadFactory(), NioIoHandler.newFactory(NioUdtProvider.MESSAGE_PROVIDER));
+        final EventLoopGroup group2 = new MultiThreadIoEventLoopGroup(
+                1, Executors.defaultThreadFactory(), NioIoHandler.newFactory(NioUdtProvider.MESSAGE_PROVIDER));
 
         final Bootstrap peerBoot1 = new Bootstrap();
         peerBoot1.group(group1)
diff --git a/transport-udt/src/test/java/io/netty/test/udt/nio/NioUdtByteRendezvousChannelTest.java b/transport-udt/src/test/java/io/netty/test/udt/nio/NioUdtByteRendezvousChannelTest.java
index 4ab18a08b30..2b6c2a607ba 100644
--- a/transport-udt/src/test/java/io/netty/test/udt/nio/NioUdtByteRendezvousChannelTest.java
+++ b/transport-udt/src/test/java/io/netty/test/udt/nio/NioUdtByteRendezvousChannelTest.java
@@ -20,7 +20,9 @@
 import com.yammer.metrics.core.Meter;
 import io.netty.bootstrap.Bootstrap;
 import io.netty.channel.ChannelFuture;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.EventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.udt.nio.NioUdtByteRendezvousChannel;
 import io.netty.channel.udt.nio.NioUdtProvider;
 import io.netty.test.udt.util.EchoByteHandler;
@@ -74,10 +76,10 @@ public void basicEcho() throws Exception {
         final EchoByteHandler handler1 = new EchoByteHandler(rate1, messageSize);
         final EchoByteHandler handler2 = new EchoByteHandler(rate2, messageSize);
 
-        final NioEventLoopGroup group1 = new NioEventLoopGroup(
-                1, Executors.defaultThreadFactory(), NioUdtProvider.BYTE_PROVIDER);
-        final NioEventLoopGroup group2 = new NioEventLoopGroup(
-                1, Executors.defaultThreadFactory(), NioUdtProvider.BYTE_PROVIDER);
+        final EventLoopGroup group1 = new MultiThreadIoEventLoopGroup(
+                1, Executors.defaultThreadFactory(), NioIoHandler.newFactory(NioUdtProvider.BYTE_PROVIDER));
+        final EventLoopGroup group2 = new MultiThreadIoEventLoopGroup(
+                1, Executors.defaultThreadFactory(), NioIoHandler.newFactory(NioUdtProvider.BYTE_PROVIDER));
 
         final Bootstrap boot1 = new Bootstrap();
         boot1.group(group1)
diff --git a/transport-udt/src/test/java/io/netty/test/udt/nio/NioUdtMessageRendezvousChannelTest.java b/transport-udt/src/test/java/io/netty/test/udt/nio/NioUdtMessageRendezvousChannelTest.java
index 8c2b90f16b7..9167cc35155 100644
--- a/transport-udt/src/test/java/io/netty/test/udt/nio/NioUdtMessageRendezvousChannelTest.java
+++ b/transport-udt/src/test/java/io/netty/test/udt/nio/NioUdtMessageRendezvousChannelTest.java
@@ -20,7 +20,9 @@
 import com.yammer.metrics.core.Meter;
 import io.netty.bootstrap.Bootstrap;
 import io.netty.channel.ChannelFuture;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.EventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.udt.nio.NioUdtMessageRendezvousChannel;
 import io.netty.channel.udt.nio.NioUdtProvider;
 import io.netty.test.udt.util.EchoMessageHandler;
@@ -77,10 +79,10 @@ public void basicEcho() throws Exception {
         final EchoMessageHandler handler1 = new EchoMessageHandler(rate1, messageSize);
         final EchoMessageHandler handler2 = new EchoMessageHandler(rate2, messageSize);
 
-        final NioEventLoopGroup group1 = new NioEventLoopGroup(
-                1, Executors.defaultThreadFactory(), NioUdtProvider.MESSAGE_PROVIDER);
-        final NioEventLoopGroup group2 = new NioEventLoopGroup(
-                1, Executors.defaultThreadFactory(), NioUdtProvider.MESSAGE_PROVIDER);
+        final EventLoopGroup group1 = new MultiThreadIoEventLoopGroup(
+                1, Executors.defaultThreadFactory(), NioIoHandler.newFactory(NioUdtProvider.MESSAGE_PROVIDER));
+        final EventLoopGroup group2 = new MultiThreadIoEventLoopGroup(
+                1, Executors.defaultThreadFactory(), NioIoHandler.newFactory(NioUdtProvider.MESSAGE_PROVIDER));
 
         final Bootstrap boot1 = new Bootstrap();
         boot1.group(group1)
diff --git a/transport/src/main/java/io/netty/channel/DefaultEventLoopGroup.java b/transport/src/main/java/io/netty/channel/DefaultEventLoopGroup.java
index d12c288a8cf..ef78fa11025 100644
--- a/transport/src/main/java/io/netty/channel/DefaultEventLoopGroup.java
+++ b/transport/src/main/java/io/netty/channel/DefaultEventLoopGroup.java
@@ -21,6 +21,7 @@
 /**
  * {@link MultithreadEventLoopGroup} which must be used for the local transport.
  */
+@Deprecated
 public class DefaultEventLoopGroup extends MultithreadEventLoopGroup {
 
     /**
diff --git a/transport/src/main/java/io/netty/channel/nio/NioIoHandler.java b/transport/src/main/java/io/netty/channel/nio/NioIoHandler.java
index e1d5ffd7000..800f5f20197 100644
--- a/transport/src/main/java/io/netty/channel/nio/NioIoHandler.java
+++ b/transport/src/main/java/io/netty/channel/nio/NioIoHandler.java
@@ -726,12 +726,24 @@ private void selectAgain() {
     }
 
     /**
-     * Returns a new {@link IoHandlerFactory} that creates {@link NioIoHandler} instances.
+     * Returns a new {@link IoHandlerFactory} that creates {@link NioIoHandler} instances
+     *
+     * @return factory                  the {@link IoHandlerFactory}.
      */
     public static IoHandlerFactory newFactory() {
         return newFactory(SelectorProvider.provider(), DefaultSelectStrategyFactory.INSTANCE);
     }
 
+    /**
+     * Returns a new {@link IoHandlerFactory} that creates {@link NioIoHandler} instances.
+     *
+     * @param selectorProvider          the {@link SelectorProvider} to use.
+     * @return factory                  the {@link IoHandlerFactory}.
+     */
+    public static IoHandlerFactory newFactory(SelectorProvider selectorProvider) {
+        return newFactory(selectorProvider, DefaultSelectStrategyFactory.INSTANCE);
+    }
+
     /**
      * Returns a new {@link IoHandlerFactory} that creates {@link NioIoHandler} instances.
      *
diff --git a/transport/src/test/java/io/netty/bootstrap/ServerBootstrapTest.java b/transport/src/test/java/io/netty/bootstrap/ServerBootstrapTest.java
index 36ed66cbc5a..7332cce6ec9 100644
--- a/transport/src/test/java/io/netty/bootstrap/ServerBootstrapTest.java
+++ b/transport/src/test/java/io/netty/bootstrap/ServerBootstrapTest.java
@@ -22,11 +22,11 @@
 import io.netty.channel.ChannelInboundHandlerAdapter;
 import io.netty.channel.ChannelInitializer;
 import io.netty.channel.ChannelOption;
-import io.netty.channel.DefaultEventLoopGroup;
 import io.netty.channel.EventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
 import io.netty.channel.local.LocalAddress;
 import io.netty.channel.local.LocalChannel;
-import io.netty.channel.local.LocalEventLoopGroup;
+import io.netty.channel.local.LocalIoHandler;
 import io.netty.channel.local.LocalServerChannel;
 import io.netty.util.AttributeKey;
 import org.junit.jupiter.api.Test;
@@ -51,7 +51,7 @@ public class ServerBootstrapTest {
     public void testHandlerRegister() throws Exception {
         final CountDownLatch latch = new CountDownLatch(1);
         final AtomicReference<Throwable> error = new AtomicReference<Throwable>();
-        LocalEventLoopGroup group = new LocalEventLoopGroup(1);
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(1, LocalIoHandler.newFactory());
         try {
             ServerBootstrap sb = new ServerBootstrap();
             sb.channel(LocalServerChannel.class)
@@ -108,7 +108,7 @@ public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception
             }
         };
 
-        EventLoopGroup group = new DefaultEventLoopGroup(1);
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(1, LocalIoHandler.newFactory());
         Channel sch = null;
         Channel cch = null;
         try {
@@ -151,7 +151,7 @@ protected void initChannel(Channel ch) throws Exception {
 
     @Test
     public void optionsAndAttributesMustBeAvailableOnChildChannelInit() throws InterruptedException {
-        EventLoopGroup group = new DefaultEventLoopGroup(1);
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(1, LocalIoHandler.newFactory());
         LocalAddress addr = new LocalAddress(UUID.randomUUID().toString());
         final AttributeKey<String> key = AttributeKey.valueOf(UUID.randomUUID().toString());
         final AtomicBoolean requestServed = new AtomicBoolean();
@@ -187,7 +187,7 @@ void mustCallInitializerExtensions() throws Exception {
         LocalAddress addr = new LocalAddress(ServerBootstrapTest.class);
         final AtomicReference<Channel> expectedServerChannel = new AtomicReference<Channel>();
         final AtomicReference<Channel> expectedChildChannel = new AtomicReference<Channel>();
-        LocalEventLoopGroup group = new LocalEventLoopGroup(1);
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(1, LocalIoHandler.newFactory());
         final ServerBootstrap sb = new ServerBootstrap();
         sb.group(group);
         sb.channel(LocalServerChannel.class);
diff --git a/transport/src/test/java/io/netty/channel/DefaultChannelPipelineTest.java b/transport/src/test/java/io/netty/channel/DefaultChannelPipelineTest.java
index fa86dd10a92..9d7ef7dd9a9 100644
--- a/transport/src/test/java/io/netty/channel/DefaultChannelPipelineTest.java
+++ b/transport/src/test/java/io/netty/channel/DefaultChannelPipelineTest.java
@@ -25,8 +25,9 @@
 import io.netty.channel.embedded.EmbeddedChannel;
 import io.netty.channel.local.LocalAddress;
 import io.netty.channel.local.LocalChannel;
+import io.netty.channel.local.LocalIoHandler;
 import io.netty.channel.local.LocalServerChannel;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.oio.OioEventLoopGroup;
 import io.netty.channel.socket.nio.NioSocketChannel;
 import io.netty.channel.socket.oio.OioSocketChannel;
@@ -85,7 +86,7 @@ public class DefaultChannelPipelineTest {
 
     @BeforeAll
     public static void beforeClass() throws Exception {
-        group = new DefaultEventLoopGroup(1);
+        group = new MultiThreadIoEventLoopGroup(1, LocalIoHandler.newFactory());
     }
 
     @AfterAll
@@ -968,8 +969,8 @@ public void testAddReplaceHandlerNotRegistered() throws Throwable {
     @Test
     @Timeout(value = 3000, unit = TimeUnit.MILLISECONDS)
     public void testHandlerAddedAndRemovedCalledInCorrectOrder() throws Throwable {
-        final EventExecutorGroup group1 = new DefaultEventExecutorGroup(1);
-        final EventExecutorGroup group2 = new DefaultEventExecutorGroup(1);
+        final EventExecutorGroup group1 = new MultiThreadIoEventLoopGroup(1, LocalIoHandler.newFactory());
+        final EventExecutorGroup group2 = new MultiThreadIoEventLoopGroup(1, LocalIoHandler.newFactory());
 
         try {
             BlockingQueue<CheckOrderHandler> addedQueue = new LinkedBlockingQueue<CheckOrderHandler>();
@@ -1012,7 +1013,7 @@ public void testHandlerAddedAndRemovedCalledInCorrectOrder() throws Throwable {
     @Test
     @Timeout(value = 3000, unit = TimeUnit.MILLISECONDS)
     public void testHandlerAddedExceptionFromChildHandlerIsPropagated() {
-        final EventExecutorGroup group1 = new DefaultEventExecutorGroup(1);
+        final EventExecutorGroup group1 = new MultiThreadIoEventLoopGroup(1, LocalIoHandler.newFactory());
         try {
             final Promise<Void> promise = group1.next().newPromise();
             final AtomicBoolean handlerAdded = new AtomicBoolean();
@@ -1037,7 +1038,7 @@ public void handlerAdded(ChannelHandlerContext ctx) throws Exception {
     @Test
     @Timeout(value = 3000, unit = TimeUnit.MILLISECONDS)
     public void testHandlerRemovedExceptionFromChildHandlerIsPropagated() {
-        final EventExecutorGroup group1 = new DefaultEventExecutorGroup(1);
+        final EventExecutorGroup group1 = new MultiThreadIoEventLoopGroup(1, LocalIoHandler.newFactory());
         try {
             final Promise<Void> promise = group1.next().newPromise();
             String handlerName = "foo";
@@ -1061,7 +1062,7 @@ public void handlerRemoved(ChannelHandlerContext ctx) throws Exception {
     @Test
     @Timeout(value = 3000, unit = TimeUnit.MILLISECONDS)
     public void testHandlerAddedThrowsAndRemovedThrowsException() throws InterruptedException {
-        final EventExecutorGroup group1 = new DefaultEventExecutorGroup(1);
+        final EventExecutorGroup group1 = new MultiThreadIoEventLoopGroup(1, LocalIoHandler.newFactory());
         try {
             final CountDownLatch latch = new CountDownLatch(1);
             final Promise<Void> promise = group1.next().newPromise();
@@ -1182,7 +1183,7 @@ public void testAddBefore() throws Throwable {
     @Test
     @Timeout(value = 3000, unit = TimeUnit.MILLISECONDS)
     public void testAddInListenerNio() {
-        testAddInListener(new NioSocketChannel(), new NioEventLoopGroup(1));
+        testAddInListener(new NioSocketChannel(), new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory()));
     }
 
     @SuppressWarnings("deprecation")
@@ -1195,7 +1196,7 @@ public void testAddInListenerOio() {
     @Test
     @Timeout(value = 3000, unit = TimeUnit.MILLISECONDS)
     public void testAddInListenerLocal() {
-        testAddInListener(new LocalChannel(), new DefaultEventLoopGroup(1));
+        testAddInListener(new LocalChannel(), new MultiThreadIoEventLoopGroup(1, LocalIoHandler.newFactory()));
     }
 
     private static void testAddInListener(Channel channel, EventLoopGroup group) {
@@ -1287,7 +1288,7 @@ public void userEventTriggered(ChannelHandlerContext ctx, Object evt) {
 
     @Test
     public void testPinExecutor() {
-        EventExecutorGroup group = new DefaultEventExecutorGroup(2);
+        EventExecutorGroup group = new MultiThreadIoEventLoopGroup(LocalIoHandler.newFactory());
         ChannelPipeline pipeline = new LocalChannel().pipeline();
         ChannelPipeline pipeline2 = new LocalChannel().pipeline();
 
@@ -1308,7 +1309,7 @@ public void testPinExecutor() {
 
     @Test
     public void testNotPinExecutor() {
-        EventExecutorGroup group = new DefaultEventExecutorGroup(2);
+        EventExecutorGroup group = new MultiThreadIoEventLoopGroup(2, LocalIoHandler.newFactory());
         ChannelPipeline pipeline = new LocalChannel().pipeline();
         pipeline.channel().config().setOption(ChannelOption.SINGLE_EVENTEXECUTOR_PER_GROUP, false);
 
@@ -1356,7 +1357,7 @@ public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
     // Test for https://github.com/netty/netty/issues/8676.
     @Test
     public void testHandlerRemovedOnlyCalledWhenHandlerAddedCalled() throws Exception {
-        EventLoopGroup group = new DefaultEventLoopGroup(1);
+        final EventLoopGroup group = new MultiThreadIoEventLoopGroup(1, LocalIoHandler.newFactory());
         try {
             final AtomicReference<Error> errorRef = new AtomicReference<Error>();
 
diff --git a/transport/src/test/java/io/netty/channel/group/DefaultChannelGroupTest.java b/transport/src/test/java/io/netty/channel/group/DefaultChannelGroupTest.java
index 7ff3fffa54f..893cfba7827 100644
--- a/transport/src/test/java/io/netty/channel/group/DefaultChannelGroupTest.java
+++ b/transport/src/test/java/io/netty/channel/group/DefaultChannelGroupTest.java
@@ -20,7 +20,8 @@
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.ChannelInboundHandlerAdapter;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.nio.NioServerSocketChannel;
 import io.netty.util.concurrent.GlobalEventExecutor;
 import org.junit.jupiter.api.Test;
@@ -30,8 +31,8 @@ public class DefaultChannelGroupTest {
     // Test for #1183
     @Test
     public void testNotThrowBlockingOperationException() throws Exception {
-        EventLoopGroup bossGroup = new NioEventLoopGroup();
-        EventLoopGroup workerGroup = new NioEventLoopGroup();
+        EventLoopGroup bossGroup = new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory());
+        EventLoopGroup workerGroup = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
 
         final ChannelGroup allChannels = new DefaultChannelGroup(GlobalEventExecutor.INSTANCE);
 
diff --git a/transport/src/test/java/io/netty/channel/nio/NioEventLoopTest.java b/transport/src/test/java/io/netty/channel/nio/NioEventLoopTest.java
index 72a92e7f2a6..ae63bc127e0 100644
--- a/transport/src/test/java/io/netty/channel/nio/NioEventLoopTest.java
+++ b/transport/src/test/java/io/netty/channel/nio/NioEventLoopTest.java
@@ -17,21 +17,20 @@
 
 import io.netty.channel.AbstractEventLoopTest;
 import io.netty.channel.Channel;
-import io.netty.channel.DefaultSelectStrategyFactory;
 import io.netty.channel.EventLoop;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.EventLoopTaskQueueFactory;
+import io.netty.channel.IoEventLoop;
+import io.netty.channel.IoEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
 import io.netty.channel.SelectStrategy;
 import io.netty.channel.SelectStrategyFactory;
 import io.netty.channel.SingleThreadEventLoop;
+import io.netty.channel.SingleThreadIoEventLoop;
 import io.netty.channel.socket.ServerSocketChannel;
 import io.netty.channel.socket.nio.NioServerSocketChannel;
 import io.netty.util.IntSupplier;
-import io.netty.util.concurrent.DefaultEventExecutorChooserFactory;
 import io.netty.util.concurrent.DefaultThreadFactory;
 import io.netty.util.concurrent.Future;
-import io.netty.util.concurrent.RejectedExecutionHandlers;
-import io.netty.util.concurrent.ThreadPerTaskExecutor;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.Timeout;
 
@@ -41,13 +40,10 @@
 import java.nio.channels.Selector;
 import java.nio.channels.SocketChannel;
 import java.nio.channels.spi.SelectorProvider;
-import java.util.Queue;
 import java.util.concurrent.Callable;
 import java.util.concurrent.CountDownLatch;
-import java.util.concurrent.LinkedBlockingQueue;
 import java.util.concurrent.RejectedExecutionException;
 import java.util.concurrent.TimeUnit;
-import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicReference;
 
 import static org.hamcrest.MatcherAssert.assertThat;
@@ -62,7 +58,7 @@ public class NioEventLoopTest extends AbstractEventLoopTest {
 
     @Override
     protected EventLoopGroup newEventLoopGroup() {
-        return new NioEventLoopGroup();
+        return new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
     }
 
     @Override
@@ -103,7 +99,7 @@ public void run() {
 
     @Test
     public void testScheduleBigDelayNotOverflow() {
-        EventLoopGroup group = new NioEventLoopGroup(1);
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory());
 
         final EventLoop el = group.next();
         Future<?> future = el.schedule(new Runnable() {
@@ -164,8 +160,8 @@ public void run() {
     @Test
     @Timeout(value = 3000, unit = TimeUnit.MILLISECONDS)
     public void testSelectableChannel() throws Exception {
-        NioEventLoopGroup group = new NioEventLoopGroup(1);
-        NioEventLoop loop = (NioEventLoop) group.next();
+        IoEventLoopGroup group = new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory());
+        IoEventLoop loop = group.next();
 
         try {
             Channel channel = new NioServerSocketChannel();
@@ -178,16 +174,12 @@ public void testSelectableChannel() throws Exception {
 
             final CountDownLatch latch = new CountDownLatch(1);
 
-            loop.register(selectableChannel, SelectionKey.OP_CONNECT, new NioTask<SocketChannel>() {
+            loop.register(new NioSelectableChannelIoHandle<SocketChannel>(selectableChannel) {
                 @Override
-                public void channelReady(SocketChannel ch, SelectionKey key) {
+                protected void handle(SocketChannel channel, SelectionKey key) {
                     latch.countDown();
                 }
-
-                @Override
-                public void channelUnregistered(SocketChannel ch, Throwable cause) {
-                }
-            });
+            }, NioIoOps.valueOf(SelectionKey.OP_CONNECT));
 
             latch.await();
 
@@ -210,8 +202,8 @@ public void run() {
         };
         // Just run often enough to trigger it normally.
         for (int i = 0; i < 1000; i++) {
-            NioEventLoopGroup group = new NioEventLoopGroup(1);
-            final NioEventLoop loop = (NioEventLoop) group.next();
+            EventLoopGroup group = new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory());
+            final EventLoop loop = group.next();
 
             Thread t = new Thread(new Runnable() {
                 @Override
@@ -278,10 +270,9 @@ public int calculateStrategy(IntSupplier selectSupplier, boolean hasTasks) throw
     @Test
     @Timeout(value = 3000, unit = TimeUnit.MILLISECONDS)
     public void testChannelsRegistered() throws Exception {
-        NioEventLoopGroup group = new NioEventLoopGroup(1);
-        final NioEventLoop loop = (NioEventLoop) group.next();
-
+        EventLoopGroup group = new NioEventLoopGroup(1);
         try {
+            final SingleThreadIoEventLoop loop = (SingleThreadIoEventLoop) group.next();
             final Channel ch1 = new NioServerSocketChannel();
             final Channel ch2 = new NioServerSocketChannel();
 
@@ -314,35 +305,4 @@ public Integer call() {
             }
         }).get(1, TimeUnit.SECONDS);
     }
-
-    @Test
-    public void testCustomQueue()  {
-        final AtomicBoolean called = new AtomicBoolean();
-        NioEventLoopGroup group = new NioEventLoopGroup(1,
-                new ThreadPerTaskExecutor(new DefaultThreadFactory(NioEventLoopGroup.class)),
-                DefaultEventExecutorChooserFactory.INSTANCE, SelectorProvider.provider(),
-                DefaultSelectStrategyFactory.INSTANCE, RejectedExecutionHandlers.reject(),
-                new EventLoopTaskQueueFactory() {
-                    @Override
-                    public Queue<Runnable> newTaskQueue(int maxCapacity) {
-                        called.set(true);
-                        return new LinkedBlockingQueue<Runnable>(maxCapacity);
-                    }
-        });
-
-        final NioEventLoop loop = (NioEventLoop) group.next();
-
-        try {
-            loop.submit(new Runnable() {
-                @Override
-                public void run() {
-                    // NOOP.
-                }
-            }).syncUninterruptibly();
-            assertTrue(called.get());
-        } finally {
-            group.shutdownGracefully();
-        }
-    }
-
 }
diff --git a/transport/src/test/java/io/netty/channel/pool/AbstractChannelPoolMapTest.java b/transport/src/test/java/io/netty/channel/pool/AbstractChannelPoolMapTest.java
index 7a257ef3c21..9f7fe4f414b 100644
--- a/transport/src/test/java/io/netty/channel/pool/AbstractChannelPoolMapTest.java
+++ b/transport/src/test/java/io/netty/channel/pool/AbstractChannelPoolMapTest.java
@@ -19,9 +19,10 @@
 import io.netty.channel.Channel;
 import io.netty.channel.EventLoop;
 import io.netty.channel.EventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
 import io.netty.channel.local.LocalAddress;
 import io.netty.channel.local.LocalChannel;
-import io.netty.channel.local.LocalEventLoopGroup;
+import io.netty.channel.local.LocalIoHandler;
 import io.netty.util.concurrent.EventExecutor;
 import io.netty.util.concurrent.Future;
 import io.netty.util.concurrent.GenericFutureListener;
@@ -43,7 +44,7 @@
 public class AbstractChannelPoolMapTest {
     @Test
     public void testMap() throws Exception {
-        EventLoopGroup group = new LocalEventLoopGroup();
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(LocalIoHandler.newFactory());
         LocalAddress addr = new LocalAddress(getLocalAddrId());
         final Bootstrap cb = new Bootstrap();
         cb.remoteAddress(addr);
@@ -85,7 +86,7 @@ public void execute() throws Throwable {
 
     @Test
     public void testRemoveClosesChannelPool() {
-        EventLoopGroup group = new LocalEventLoopGroup();
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(LocalIoHandler.newFactory());
         LocalAddress addr = new LocalAddress(getLocalAddrId());
         final Bootstrap cb = new Bootstrap();
         cb.remoteAddress(addr);
@@ -113,7 +114,7 @@ protected TestPool newPool(EventLoop key) {
 
     @Test
     public void testCloseClosesPoolsImmediately() {
-        EventLoopGroup group = new LocalEventLoopGroup();
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(LocalIoHandler.newFactory());
         LocalAddress addr = new LocalAddress(getLocalAddrId());
         final Bootstrap cb = new Bootstrap();
         cb.remoteAddress(addr);
diff --git a/transport/src/test/java/io/netty/channel/socket/nio/NioDatagramChannelTest.java b/transport/src/test/java/io/netty/channel/socket/nio/NioDatagramChannelTest.java
index fc89f805a3f..e0c56c9b8c0 100644
--- a/transport/src/test/java/io/netty/channel/socket/nio/NioDatagramChannelTest.java
+++ b/transport/src/test/java/io/netty/channel/socket/nio/NioDatagramChannelTest.java
@@ -19,8 +19,10 @@
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.ChannelInboundHandlerAdapter;
 import io.netty.channel.ChannelOption;
+import io.netty.channel.EventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
 import io.netty.channel.group.DefaultChannelGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.DatagramChannel;
 import io.netty.util.ReferenceCountUtil;
 import io.netty.util.concurrent.GlobalEventExecutor;
@@ -41,7 +43,7 @@ public class NioDatagramChannelTest extends AbstractNioChannelTest<NioDatagramCh
     @Test
     public void testBindMultiple() throws Exception {
         DefaultChannelGroup channelGroup = new DefaultChannelGroup(GlobalEventExecutor.INSTANCE);
-        NioEventLoopGroup group = new NioEventLoopGroup();
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
         try {
             for (int i = 0; i < 100; i++) {
                 Bootstrap udpBootstrap = new Bootstrap();
diff --git a/transport/src/test/java/io/netty/channel/socket/nio/NioServerDomainSocketChannelTest.java b/transport/src/test/java/io/netty/channel/socket/nio/NioServerDomainSocketChannelTest.java
index 7688f60d4be..94e7757a3b5 100644
--- a/transport/src/test/java/io/netty/channel/socket/nio/NioServerDomainSocketChannelTest.java
+++ b/transport/src/test/java/io/netty/channel/socket/nio/NioServerDomainSocketChannelTest.java
@@ -17,7 +17,8 @@
 
 import io.netty.channel.Channel;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.condition.EnabledForJreRange;
 import org.junit.jupiter.api.condition.JRE;
@@ -46,7 +47,7 @@ public class NioServerDomainSocketChannelTest extends AbstractNioDomainChannelTe
     public void testCloseOnError() throws Exception {
         ServerSocketChannel jdkChannel = NioServerDomainSocketChannel.newChannel(SelectorProvider.provider());
         NioServerDomainSocketChannel serverSocketChannel = new NioServerDomainSocketChannel(jdkChannel);
-        EventLoopGroup group = new NioEventLoopGroup(1);
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory());
         File file = newRandomTmpFile();
         try {
             group.register(serverSocketChannel).syncUninterruptibly();
@@ -63,7 +64,7 @@ public void testCloseOnError() throws Exception {
     @Test
     public void testIsActiveFalseAfterClose() throws Exception {
         NioServerDomainSocketChannel serverSocketChannel = new NioServerDomainSocketChannel();
-        EventLoopGroup group = new NioEventLoopGroup(1);
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory());
         File file = newRandomTmpFile();
         try {
             group.register(serverSocketChannel).syncUninterruptibly();
@@ -85,7 +86,7 @@ public void testIsActiveFalseAfterClose() throws Exception {
     @ValueSource(booleans = { false, true })
     public void testCreateChannelFromJdkChannel(boolean bindJdkChannel) throws Exception {
         File file = newRandomTmpFile();
-        EventLoopGroup group = new NioEventLoopGroup(1);
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory());
         try {
             SocketAddress localAddress = newUnixDomainSocketAddress(file.getAbsolutePath());
             ServerSocketChannel jdkChannel = NioServerDomainSocketChannel.newChannel(SelectorProvider.provider());
diff --git a/transport/src/test/java/io/netty/channel/socket/nio/NioServerSocketChannelTest.java b/transport/src/test/java/io/netty/channel/socket/nio/NioServerSocketChannelTest.java
index fd8de0936ca..e4bc1cc6ec3 100644
--- a/transport/src/test/java/io/netty/channel/socket/nio/NioServerSocketChannelTest.java
+++ b/transport/src/test/java/io/netty/channel/socket/nio/NioServerSocketChannelTest.java
@@ -17,8 +17,9 @@
 
 import io.netty.channel.Channel;
 import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
 
+import io.netty.channel.nio.NioIoHandler;
 import org.junit.jupiter.api.Test;
 
 import java.io.IOException;
@@ -37,7 +38,7 @@ public class NioServerSocketChannelTest extends AbstractNioChannelTest<NioServer
     public void testCloseOnError() throws Exception {
         ServerSocketChannel jdkChannel = ServerSocketChannel.open();
         NioServerSocketChannel serverSocketChannel = new NioServerSocketChannel(jdkChannel);
-        EventLoopGroup group = new NioEventLoopGroup(1);
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory());
         try {
             group.register(serverSocketChannel).syncUninterruptibly();
             serverSocketChannel.bind(new InetSocketAddress(0)).syncUninterruptibly();
@@ -52,7 +53,7 @@ public void testCloseOnError() throws Exception {
     @Test
     public void testIsActiveFalseAfterClose()  {
         NioServerSocketChannel serverSocketChannel = new NioServerSocketChannel();
-        EventLoopGroup group = new NioEventLoopGroup(1);
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory());
         try {
             group.register(serverSocketChannel).syncUninterruptibly();
             Channel channel = serverSocketChannel.bind(new InetSocketAddress(0)).syncUninterruptibly().channel();
diff --git a/transport/src/test/java/io/netty/channel/socket/nio/NioSocketChannelTest.java b/transport/src/test/java/io/netty/channel/socket/nio/NioSocketChannelTest.java
index 7fbd6fc1412..220d0adaea9 100644
--- a/transport/src/test/java/io/netty/channel/socket/nio/NioSocketChannelTest.java
+++ b/transport/src/test/java/io/netty/channel/socket/nio/NioSocketChannelTest.java
@@ -29,8 +29,9 @@
 import io.netty.channel.ChannelPipeline;
 import io.netty.channel.EventLoop;
 import io.netty.channel.EventLoopGroup;
+import io.netty.channel.MultiThreadIoEventLoopGroup;
 import io.netty.channel.SimpleChannelInboundHandler;
-import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.SocketChannel;
 import io.netty.util.CharsetUtil;
 import io.netty.util.NetUtil;
@@ -68,7 +69,7 @@ public class NioSocketChannelTest extends AbstractNioChannelTest<NioSocketChanne
      */
     @Test
     public void testFlushCloseReentrance() throws Exception {
-        NioEventLoopGroup group = new NioEventLoopGroup(1);
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory());
         try {
             final Queue<ChannelFuture> futures = new LinkedBlockingQueue<ChannelFuture>();
 
@@ -125,7 +126,7 @@ public void channelActive(ChannelHandlerContext ctx) throws Exception {
      */
     @Test
     public void testFlushAfterGatheredFlush() throws Exception {
-        NioEventLoopGroup group = new NioEventLoopGroup(1);
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory());
         try {
             ServerBootstrap sb = new ServerBootstrap();
             sb.group(group).channel(NioServerSocketChannel.class);
@@ -176,7 +177,7 @@ public void testChannelReRegisterReadDifferentEventLoop() throws Exception {
     }
 
     private static void testChannelReRegisterRead(final boolean sameEventLoop) throws Exception {
-        final EventLoopGroup group = new NioEventLoopGroup(2);
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(2, NioIoHandler.newFactory());
         final CountDownLatch latch = new CountDownLatch(1);
 
         // Just some random bytes
@@ -255,7 +256,7 @@ public void operationComplete(ChannelFuture cf) {
     @Test
     @Timeout(value = 3000, unit = TimeUnit.MILLISECONDS)
     public void testShutdownOutputAndClose() throws IOException {
-        NioEventLoopGroup group = new NioEventLoopGroup(1);
+        EventLoopGroup group = new MultiThreadIoEventLoopGroup(1, NioIoHandler.newFactory());
         ServerSocket socket = new ServerSocket();
         socket.bind(new InetSocketAddress(0));
         Socket accepted = null;