Remove Unused Imports (#11546)

Motivation:
There are lots of imports which are unused. We should get rid of them to make the code look better,

Modification:
Removed unused imports.

Result:
No unused imports.

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

@@ -21,7 +21,6 @@ import io.netty.util.CharsetUtil;
 import io.netty.util.IllegalReferenceCountException;
 import io.netty.util.ResourceLeakDetector;
 import io.netty.util.ResourceLeakDetectorFactory;
-import io.netty.util.internal.PlatformDependent;
 import io.netty.util.internal.StringUtil;
 import io.netty.util.internal.SystemPropertyUtil;
 import io.netty.util.internal.logging.InternalLogger;

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

@@ -16,7 +16,6 @@ package io.netty.buffer;
 
 import io.netty.util.internal.ObjectPool;
 import io.netty.util.internal.ObjectPool.Handle;
-import io.netty.util.internal.ObjectPool.ObjectCreator;
 import io.netty.util.internal.PlatformDependent;
 
 import java.io.IOException;

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

@@ -18,7 +18,6 @@ package io.netty.buffer;
 
 import io.netty.util.internal.ObjectPool;
 import io.netty.util.internal.ObjectPool.Handle;
-import io.netty.util.internal.ObjectPool.ObjectCreator;
 import io.netty.util.internal.PlatformDependent;
 
 import java.io.IOException;

buffer/src/main/java/io/netty/buffer/api/Buffer.java

@@ -16,7 +16,6 @@
 package io.netty.buffer.api;
 
 import java.nio.ByteBuffer;
-import java.nio.ByteOrder;
 
 /**
  * A life cycled buffer of memory, with separate reader and writer offsets.

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

@@ -16,7 +16,6 @@
 
 package io.netty.buffer;
 
-import io.netty.util.internal.PlatformDependent;
 import org.junit.jupiter.api.Test;
 
 import java.nio.ByteBuffer;

codec-http/src/main/java/io/netty/handler/codec/http/websocketx/WebSocketServerHandshaker00.java

@@ -20,7 +20,6 @@ import io.netty.buffer.Unpooled;
 import io.netty.channel.Channel;
 import io.netty.channel.ChannelFuture;
 import io.netty.channel.ChannelHandlerContext;
-import io.netty.channel.ChannelOutboundInvoker;
 import io.netty.channel.ChannelPromise;
 import io.netty.handler.codec.http.DefaultFullHttpResponse;
 import io.netty.handler.codec.http.FullHttpRequest;

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

@@ -25,7 +25,6 @@ import io.netty.handler.codec.http.HttpRequest;
 import io.netty.handler.codec.http.HttpResponse;
 import io.netty.handler.codec.http.HttpResponseStatus;
 import io.netty.handler.codec.http.HttpVersion;
-import io.netty.util.internal.ObjectUtil;
 
 import java.util.Objects;
 

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

@@ -31,11 +31,9 @@ import io.netty.handler.codec.compression.ZlibWrapper;
 import io.netty.util.CharsetUtil;
 import io.netty.util.ReferenceCountUtil;
 import io.netty.util.internal.PlatformDependent;
-import org.apache.commons.io.IOUtils;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.condition.DisabledIf;
 
-import java.io.InputStream;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Queue;
@@ -51,7 +49,6 @@ import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertNull;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 import static org.junit.jupiter.api.Assertions.fail;
-import static org.junit.jupiter.api.Assumptions.assumeFalse;
 
 public class HttpContentDecoderTest {
     private static final String HELLO_WORLD = "hello, world";

codec-http/src/test/java/io/netty/handler/codec/http/multipart/DefaultHttpDataFactoryTest.java

@@ -29,7 +29,6 @@ import static io.netty.handler.codec.http.HttpVersion.HTTP_1_1;
 import static io.netty.handler.codec.http.multipart.HttpPostBodyUtil.DEFAULT_TEXT_CONTENT_TYPE;
 import static io.netty.util.CharsetUtil.UTF_8;
 import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertNull;
 import static org.junit.jupiter.api.Assertions.assertTrue;

codec-http2/src/main/java/io/netty/handler/codec/http2/DecoratingHttp2ConnectionDecoder.java

@@ -20,8 +20,6 @@ import io.netty.buffer.ByteBuf;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.util.internal.UnstableApi;
 
-import java.util.List;
-
 /**
  * Decorator around another {@link Http2ConnectionDecoder} instance.
  */

codec-http2/src/main/java/io/netty/handler/codec/http2/DefaultHttp2Connection.java

@@ -16,7 +16,6 @@
 package io.netty.handler.codec.http2;
 
 import io.netty.buffer.ByteBuf;
-import io.netty.channel.ChannelPromise;
 import io.netty.handler.codec.http2.Http2Stream.State;
 import io.netty.util.collection.IntObjectHashMap;
 import io.netty.util.collection.IntObjectMap;

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

@@ -34,7 +34,6 @@ package io.netty.handler.codec.http2;
 import io.netty.buffer.ByteBuf;
 import io.netty.util.AsciiString;
 import io.netty.util.ByteProcessor;
-import io.netty.util.internal.PlatformDependent;
 
 import static java.util.Objects.requireNonNull;
 

codec-http2/src/main/java/io/netty/handler/codec/http2/Http2ConnectionDecoder.java

@@ -19,7 +19,6 @@ import io.netty.channel.ChannelHandlerContext;
 import io.netty.util.internal.UnstableApi;
 
 import java.io.Closeable;
-import java.util.List;
 
 /**
  * Handler for inbound traffic on behalf of {@link Http2ConnectionHandler}. Performs basic protocol

codec-http2/src/test/java/io/netty/handler/codec/http2/DefaultHttp2FrameWriterTest.java

@@ -38,7 +38,6 @@ import java.util.Arrays;
 
 import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.mockito.Mockito.*;
 
 /**

codec-http2/src/test/java/io/netty/handler/codec/http2/DefaultHttp2RemoteFlowControllerTest.java

@@ -42,7 +42,6 @@ import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertSame;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
-import static org.junit.jupiter.api.Assertions.fail;
 import static org.mockito.Mockito.any;
 import static org.mockito.Mockito.anyInt;
 import static org.mockito.Mockito.atLeastOnce;

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

@@ -25,7 +25,6 @@ import static io.netty.handler.codec.http2.Http2CodecUtil.DEFAULT_HEADER_LIST_SI
 import static io.netty.handler.codec.http2.Http2CodecUtil.MAX_HEADER_TABLE_SIZE;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
-import static org.junit.jupiter.api.Assertions.assertTrue;
 import static org.mockito.Mockito.mock;
 
 public class HpackEncoderTest {

codec-http2/src/test/java/io/netty/handler/codec/http2/Http2ControlFrameLimitEncoderTest.java

@@ -43,7 +43,6 @@ import java.util.Queue;
 import static io.netty.handler.codec.http2.Http2CodecUtil.*;
 import static io.netty.handler.codec.http2.Http2Error.CANCEL;
 import static io.netty.handler.codec.http2.Http2Error.ENHANCE_YOUR_CALM;
-import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 import static org.mockito.Mockito.*;

codec-mqtt/src/test/java/io/netty/handler/codec/mqtt/MqttTestUtils.java

@@ -19,8 +19,6 @@ package io.netty.handler.codec.mqtt;
 import io.netty.buffer.ByteBufUtil;
 
 import java.util.List;
-import java.util.Set;
-import java.util.stream.Collectors;
 
 import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertEquals;

codec/src/main/java/io/netty/handler/codec/DatagramPacketDecoder.java

@@ -23,8 +23,6 @@ import io.netty.channel.ChannelPipeline;
 import io.netty.channel.socket.DatagramPacket;
 import io.netty.handler.codec.protobuf.ProtobufDecoder;
 
-import java.util.List;
-
 /**
  * A decoder that decodes the content of the received {@link DatagramPacket} using
  * the specified {@link ByteBuf} decoder. E.g.,

codec/src/main/java/io/netty/handler/codec/LengthFieldBasedFrameDecoder.java

@@ -23,7 +23,6 @@ import java.nio.ByteOrder;
 
 import io.netty.buffer.ByteBuf;
 import io.netty.channel.ChannelHandlerContext;
-import io.netty.handler.codec.serialization.ObjectDecoder;
 
 /**
  * A decoder that splits the received {@link ByteBuf}s dynamically by the

codec/src/main/java/io/netty/handler/codec/base64/Base64Decoder.java

@@ -26,8 +26,6 @@ import io.netty.handler.codec.DelimiterBasedFrameDecoder;
 import io.netty.handler.codec.Delimiters;
 import io.netty.handler.codec.MessageToMessageDecoder;
 
-import java.util.List;
-
 /**
  * Decodes a Base64-encoded {@link ByteBuf} or US-ASCII {@link String}
  * into a {@link ByteBuf}.  Please note that this decoder must be used

codec/src/main/java/io/netty/handler/codec/bytes/ByteArrayDecoder.java

@@ -23,8 +23,6 @@ import io.netty.handler.codec.LengthFieldBasedFrameDecoder;
 import io.netty.handler.codec.LengthFieldPrepender;
 import io.netty.handler.codec.MessageToMessageDecoder;
 
-import java.util.List;
-
 /**
  * Decodes a received {@link ByteBuf} into an array of bytes.
  * A typical setup for TCP/IP would be:

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

@@ -24,7 +24,6 @@ import io.netty.handler.codec.ByteToMessageDecoder;
 import io.netty.util.internal.ObjectUtil;
 
 import java.nio.ByteBuffer;
-import java.util.List;
 
 /**
  * Uncompresses a {@link ByteBuf} encoded with the brotli format.

codec/src/main/java/io/netty/handler/codec/protobuf/ProtobufDecoderNano.java

@@ -19,8 +19,6 @@ import static java.util.Objects.requireNonNull;
 
 import com.google.protobuf.nano.MessageNano;
 
-import java.util.List;
-
 import io.netty.buffer.ByteBuf;
 import io.netty.buffer.ByteBufUtil;
 import io.netty.channel.ChannelHandler.Sharable;

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

@@ -22,8 +22,6 @@ import io.netty.channel.embedded.EmbeddedChannel;
 import io.netty.util.CharsetUtil;
 import io.netty.util.ReferenceCountUtil;
 import io.netty.util.internal.EmptyArrays;
-import org.junit.jupiter.api.AfterEach;
-import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
 import java.util.Arrays;

common/src/main/java/io/netty/util/concurrent/SingleThreadEventExecutor.java

@@ -15,7 +15,6 @@
  */
 package io.netty.util.concurrent;
 
-import io.netty.util.internal.PlatformDependent;
 import io.netty.util.internal.SystemPropertyUtil;
 import io.netty.util.internal.ThreadExecutorMap;
 import io.netty.util.internal.logging.InternalLogger;

common/src/test/java/io/netty/util/DomainWildcardMappingBuilderTest.java

@@ -18,8 +18,6 @@ package io.netty.util;
 
 import org.junit.jupiter.api.Test;
 
-import java.util.Map;
-
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 

common/src/test/java/io/netty/util/concurrent/DefaultPromiseTest.java

@@ -30,12 +30,10 @@ import java.util.concurrent.BlockingQueue;
 import java.util.concurrent.CancellationException;
 import java.util.concurrent.CompletionException;
 import java.util.concurrent.CountDownLatch;
-import java.util.concurrent.ExecutionException;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 import java.util.concurrent.LinkedBlockingQueue;
 import java.util.concurrent.TimeUnit;
-import java.util.concurrent.TimeoutException;
 import java.util.concurrent.atomic.AtomicInteger;
 
 import static java.lang.Math.max;
@@ -109,23 +107,21 @@ public class DefaultPromiseTest {
     }
 
     @Test
-    public void testCancellationExceptionIsThrownWhenBlockingGet() throws InterruptedException, ExecutionException {
+    public void testCancellationExceptionIsThrownWhenBlockingGet() throws Exception {
         final Promise<Void> promise = new DefaultPromise<>(ImmediateEventExecutor.INSTANCE);
         assertTrue(promise.cancel(false));
         assertThrows(CancellationException.class, promise::get);
     }
 
     @Test
-    public void testCancellationExceptionIsThrownWhenBlockingGetWithTimeout() throws InterruptedException,
-            ExecutionException, TimeoutException {
+    public void testCancellationExceptionIsThrownWhenBlockingGetWithTimeout() throws Exception {
         final Promise<Void> promise = new DefaultPromise<>(ImmediateEventExecutor.INSTANCE);
         assertTrue(promise.cancel(false));
         assertThrows(CancellationException.class, () -> promise.get(1, TimeUnit.SECONDS));
     }
 
     @Test
-    public void testCancellationExceptionIsReturnedAsCause() throws InterruptedException,
-    ExecutionException, TimeoutException {
+    public void testCancellationExceptionIsReturnedAsCause() throws Exception {
         final Promise<Void> promise = new DefaultPromise<>(ImmediateEventExecutor.INSTANCE);
         assertTrue(promise.cancel(false));
         assertThat(promise.cause(), instanceOf(CancellationException.class));

example/src/main/java/io/netty/example/discard/DiscardClientHandler.java

@@ -16,7 +16,6 @@
 package io.netty.example.discard;
 
 import io.netty.buffer.ByteBuf;
-import io.netty.channel.ChannelFuture;
 import io.netty.channel.ChannelFutureListener;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.SimpleChannelInboundHandler;

example/src/main/java/io/netty/example/discard/DiscardServer.java

@@ -17,7 +17,6 @@ package io.netty.example.discard;
 
 import io.netty.bootstrap.ServerBootstrap;
 import io.netty.channel.Channel;
-import io.netty.channel.ChannelFuture;
 import io.netty.channel.ChannelInitializer;
 import io.netty.channel.ChannelPipeline;
 import io.netty.channel.EventLoopGroup;

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

@@ -17,7 +17,6 @@ package io.netty.example.uptime;
 
 import io.netty.bootstrap.ServerBootstrap;
 import io.netty.channel.Channel;
-import io.netty.channel.ChannelFuture;
 import io.netty.channel.ChannelInitializer;
 import io.netty.channel.EventLoopGroup;
 import io.netty.channel.MultithreadEventLoopGroup;

handler/src/main/java/io/netty/handler/ipfilter/UniqueIpFilter.java

@@ -16,7 +16,6 @@
 package io.netty.handler.ipfilter;
 
 import io.netty.channel.Channel;
-import io.netty.channel.ChannelFuture;
 import io.netty.channel.ChannelFutureListener;
 import io.netty.channel.ChannelHandler;
 import io.netty.channel.ChannelHandlerContext;

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

@@ -15,10 +15,6 @@
  */
 package io.netty.handler.ssl;
 
-import io.netty.util.internal.ObjectUtil;
-
-import java.util.Arrays;
-
 /**
  * Cipher suites
  */

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

@@ -18,8 +18,6 @@ package io.netty.handler.ssl;
 import java.util.Collections;
 import java.util.List;
 
-import javax.net.ssl.SSLEngine;
-
 /**
  * The {@link JdkApplicationProtocolNegotiator} to use if you do not care about NPN or ALPN and are using
  * {@link SslProvider#JDK}.

handler/src/main/java/io/netty/handler/ssl/OpenSslCachingX509KeyManagerFactory.java

@@ -21,7 +21,6 @@ import javax.net.ssl.KeyManager;
 import javax.net.ssl.KeyManagerFactory;
 import javax.net.ssl.KeyManagerFactorySpi;
 import javax.net.ssl.ManagerFactoryParameters;
-import javax.net.ssl.X509ExtendedKeyManager;
 import javax.net.ssl.X509KeyManager;
 import java.security.InvalidAlgorithmParameterException;
 import java.security.KeyStore;

handler/src/main/java/io/netty/handler/ssl/OpenSslTlsv13X509ExtendedTrustManager.java

@@ -15,8 +15,6 @@
  */
 package io.netty.handler.ssl;
 
-import io.netty.util.internal.PlatformDependent;
-
 import javax.net.ssl.SSLEngine;
 import javax.net.ssl.SSLPeerUnverifiedException;
 import javax.net.ssl.SSLSession;

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

@@ -67,7 +67,6 @@ import javax.net.ssl.X509TrustManager;
 
 import static io.netty.handler.ssl.OpenSsl.DEFAULT_CIPHERS;
 import static io.netty.handler.ssl.OpenSsl.availableJavaCipherSuites;
-import static io.netty.handler.ssl.OpenSsl.ensureAvailability;
 import static io.netty.util.internal.ObjectUtil.checkNonEmpty;
 import static io.netty.util.internal.ObjectUtil.checkPositiveOrZero;
 import static java.util.Objects.requireNonNull;

handler/src/main/java/io/netty/handler/ssl/util/SelfSignedCertificate.java

@@ -30,7 +30,6 @@ import java.io.FileInputStream;
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.OutputStream;
-import java.nio.file.Files;
 import java.security.KeyPair;
 import java.security.KeyPairGenerator;
 import java.security.NoSuchAlgorithmException;

microbench/src/main/java/io/netty/handler/codec/http2/HpackDecoderBenchmark.java

@@ -44,7 +44,6 @@ import org.openjdk.jmh.infra.Blackhole;
 
 import static io.netty.buffer.Unpooled.wrappedBuffer;
 import static io.netty.handler.codec.http2.HpackBenchmarkUtil.http2Headers;
-import static io.netty.handler.codec.http2.Http2CodecUtil.DEFAULT_HEADER_LIST_SIZE;
 
 public class HpackDecoderBenchmark extends AbstractMicrobenchmark {
 

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

@@ -22,7 +22,6 @@ import io.netty.channel.AddressedEnvelope;
 import io.netty.channel.Channel;
 import io.netty.channel.ChannelFactory;
 import io.netty.channel.ChannelFuture;
-import io.netty.channel.ChannelFutureListener;
 import io.netty.channel.ChannelHandler;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.ChannelInitializer;

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

@@ -18,7 +18,6 @@ package io.netty.resolver.dns;
 import static java.util.Objects.requireNonNull;
 
 import io.netty.handler.codec.dns.DnsQuestion;
-import io.netty.util.internal.EmptyArrays;
 
 import java.net.InetSocketAddress;
 

transport-native-epoll/src/test/java/io/netty/channel/epoll/EpollSocketTcpMd5Test.java

@@ -37,7 +37,6 @@ import java.util.concurrent.ExecutionException;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.junit.jupiter.api.Assertions.assertThrows;
-import static org.junit.jupiter.api.Assertions.assertTrue;
 
 public class EpollSocketTcpMd5Test {
     private static final byte[] SERVER_KEY = "abc".getBytes(CharsetUtil.US_ASCII);

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

@@ -20,8 +20,6 @@ import io.netty.buffer.ByteBuf;
 import io.netty.buffer.ByteBufAllocator;
 import io.netty.channel.AddressedEnvelope;
 import io.netty.channel.ChannelFuture;
-import io.netty.channel.ChannelMetadata;
-import io.netty.channel.ChannelOutboundBuffer;
 import io.netty.channel.ChannelPipeline;
 import io.netty.channel.ChannelPromise;
 import io.netty.channel.DefaultAddressedEnvelope;
@@ -37,7 +35,6 @@ import io.netty.util.UncheckedBooleanSupplier;
 import io.netty.util.internal.StringUtil;
 import io.netty.util.internal.UnstableApi;
 
-import java.io.IOException;
 import java.net.InetAddress;
 import java.net.InetSocketAddress;
 import java.net.NetworkInterface;

transport-native-kqueue/src/test/java/io/netty/channel/kqueue/KQueueDatagramUnicastIPv6Test.java

@@ -16,10 +16,8 @@
 package io.netty.channel.kqueue;
 
 import io.netty.bootstrap.Bootstrap;
-import io.netty.channel.socket.InternetProtocolFamily;
 import io.netty.testsuite.transport.TestsuitePermutation;
 import io.netty.testsuite.transport.socket.DatagramUnicastIPv6Test;
-import io.netty.testsuite.transport.socket.DatagramUnicastTest;
 
 import java.util.List;
 

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

@@ -17,7 +17,6 @@ package io.netty.channel.kqueue;
 
 import io.netty.bootstrap.Bootstrap;
 import io.netty.bootstrap.ServerBootstrap;
-import io.netty.handler.ssl.SslContext;
 import io.netty.testsuite.transport.TestsuitePermutation;
 import io.netty.testsuite.transport.socket.SocketSslSessionReuseTest;
 

transport-native-unix-common-tests/src/main/java/io/netty/channel/unix/tests/UnixTestUtils.java

@@ -16,7 +16,6 @@
 package io.netty.channel.unix.tests;
 
 import io.netty.channel.unix.DomainSocketAddress;
-import io.netty.channel.unix.Socket;
 import io.netty.util.internal.PlatformDependent;
 
 import java.io.File;

transport-native-unix-common/src/main/java/io/netty/channel/unix/DomainSocketChannelConfig.java

@@ -21,7 +21,6 @@ import io.netty.channel.MessageSizeEstimator;
 import io.netty.channel.RecvByteBufAllocator;
 import io.netty.channel.WriteBufferWaterMark;
 import io.netty.channel.socket.DuplexChannelConfig;
-import io.netty.channel.socket.SocketChannelConfig;
 
 import java.net.StandardSocketOptions;