Remove useless imports and redundant type cast (#11639)

Motivation:

There are some redundant imports and unnecessary type cast

Modification:

Remove useless imports and unnecessary type cast

Result:

The code is cleaner than original

Signed-off-by: xingrufei <xingrufei@sogou-inc.com>

codec-mqtt/src/main/java/io/netty/handler/codec/mqtt/MqttMessageFactory.java

@@ -82,7 +82,7 @@ public final class MqttMessageFactory {
             case AUTH:
                 //Having MqttReasonCodeAndPropertiesVariableHeader
                 return new MqttMessage(mqttFixedHeader,
-                        (MqttReasonCodeAndPropertiesVariableHeader) variableHeader);
+                        variableHeader);
 
             default:
                 throw new IllegalArgumentException("unknown message type: " + mqttFixedHeader.messageType());

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

@@ -48,7 +48,6 @@ import java.security.cert.CertificateNotYetValidException;
 import java.security.cert.CertificateRevokedException;
 import java.security.cert.X509Certificate;
 import java.util.ArrayList;
-import java.util.Arrays;
 import java.util.Collections;
 import java.util.LinkedHashSet;
 import java.util.List;

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

@@ -25,7 +25,6 @@ import io.netty.internal.tcnative.SSL;
 import io.netty.util.CharsetUtil;
 import io.netty.util.internal.EmptyArrays;
 import io.netty.util.internal.PlatformDependent;
-import io.netty.util.internal.ResourcesUtil;
 import org.junit.AssumptionViolatedException;
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeAll;
@@ -36,7 +35,6 @@ import org.junit.jupiter.params.provider.MethodSource;
 import javax.crypto.Cipher;
 import javax.crypto.spec.IvParameterSpec;
 import javax.crypto.spec.SecretKeySpec;
-import javax.net.ssl.KeyManagerFactory;
 import javax.net.ssl.SSLEngine;
 import javax.net.ssl.SSLEngineResult;
 import javax.net.ssl.SSLEngineResult.HandshakeStatus;
@@ -44,14 +42,12 @@ import javax.net.ssl.SSLException;
 import javax.net.ssl.SSLHandshakeException;
 import javax.net.ssl.SSLParameters;
 import javax.net.ssl.X509ExtendedKeyManager;
-import java.io.File;
 import java.net.Socket;
 import java.nio.ByteBuffer;
 import java.security.AlgorithmConstraints;
 import java.security.AlgorithmParameters;
 import java.security.CryptoPrimitive;
 import java.security.Key;
-import java.security.KeyStore;
 import java.security.Principal;
 import java.security.PrivateKey;
 import java.security.cert.X509Certificate;
@@ -59,7 +55,6 @@ import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
 import java.util.Set;
-import java.util.concurrent.TimeUnit;
 
 import static io.netty.handler.ssl.OpenSslTestUtils.checkShouldUseKeyManagerFactory;
 import static io.netty.handler.ssl.ReferenceCountedOpenSslEngine.MAX_PLAINTEXT_LENGTH;

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

@@ -391,7 +391,7 @@ class EpollEventLoop extends SingleThreadEventLoop {
                     events.increase();
                 }
             } catch (Error e) {
-                throw (Error) e;
+                throw e;
             } catch (Throwable t) {
                 handleLoopException(t);
             } finally {
@@ -404,7 +404,7 @@ class EpollEventLoop extends SingleThreadEventLoop {
                         }
                     }
                 } catch (Error e) {
-                    throw (Error) e;
+                    throw e;
                 } catch (Throwable t) {
                     handleLoopException(t);
                 }

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

@@ -17,7 +17,6 @@ package io.netty.channel.epoll;
 
 import io.netty.bootstrap.Bootstrap;
 import io.netty.bootstrap.ServerBootstrap;
-import io.netty.channel.ChannelOption;
 import io.netty.testsuite.transport.TestsuitePermutation;
 import io.netty.testsuite.transport.socket.SocketConnectTest;
 

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

@@ -298,7 +298,7 @@ final class KQueueEventLoop extends SingleThreadEventLoop {
                     eventList.realloc(false);
                 }
             } catch (Error e) {
-                throw (Error) e;
+                throw e;
             } catch (Throwable t) {
                 handleLoopException(t);
             } finally {
@@ -311,7 +311,7 @@ final class KQueueEventLoop extends SingleThreadEventLoop {
                         }
                     }
                 } catch (Error e) {
-                    throw (Error) e;
+                    throw e;
                 } catch (Throwable t) {
                     handleLoopException(t);
                 }

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

@@ -516,7 +516,7 @@ public final class NioEventLoop extends SingleThreadEventLoop {
                             selector, e);
                 }
             } catch (Error e) {
-                throw (Error) e;
+                throw e;
             } catch (Throwable t) {
                 handleLoopException(t);
             } finally {
@@ -529,7 +529,7 @@ public final class NioEventLoop extends SingleThreadEventLoop {
                         }
                     }
                 } catch (Error e) {
-                    throw (Error) e;
+                    throw e;
                 } catch (Throwable t) {
                     handleLoopException(t);
                 }