diff --git a/src/main/java/io/github/yezhihao/netmc/TCPServer.java b/src/main/java/io/github/yezhihao/netmc/TCPServer.java
index cb48ad6..3484334 100644
--- a/src/main/java/io/github/yezhihao/netmc/TCPServer.java
+++ b/src/main/java/io/github/yezhihao/netmc/TCPServer.java
@@ -33,8 +33,8 @@ public class TCPServer {
     private EventLoopGroup bossGroup = null;
     private EventLoopGroup workerGroup = null;
 
-    private String name;
-    private NettyConfig config;
+    private final String name;
+    private final NettyConfig config;
 
     public TCPServer(String name, NettyConfig config) {
         this.name = name;
@@ -53,8 +53,8 @@ public class TCPServer {
                     .childOption(NioChannelOption.TCP_NODELAY, true)
                     .childHandler(new ChannelInitializer<NioSocketChannel>() {
 
-                        private MessageEncoderWrapper messageEncoderWrapper = new MessageEncoderWrapper(config.encoder);
-                        private MessageDecoderWrapper messageDecoderWrapper = new MessageDecoderWrapper(config.decoder);
+                        private final MessageEncoderWrapper messageEncoderWrapper = new MessageEncoderWrapper(config.encoder);
+                        private final MessageDecoderWrapper messageDecoderWrapper = new MessageDecoderWrapper(config.decoder);
 
                         @Override
                         public void initChannel(NioSocketChannel channel) {
@@ -71,7 +71,7 @@ public class TCPServer {
             log.warn("==={}启动成功, port={}===", name, config.port);
             channelFuture.channel().closeFuture().sync();
         } catch (Exception e) {
-            log.warn("==={}出现异常, port={}===", e);
+            log.warn("==={}出现异常, port={}===", e, config.port);
         } finally {
             stop();
         }
diff --git a/src/main/java/io/github/yezhihao/netmc/TCPServerHandler.java b/src/main/java/io/github/yezhihao/netmc/TCPServerHandler.java
index 1825407..707f1b3 100644
--- a/src/main/java/io/github/yezhihao/netmc/TCPServerHandler.java
+++ b/src/main/java/io/github/yezhihao/netmc/TCPServerHandler.java
@@ -27,13 +27,13 @@ public class TCPServerHandler extends ChannelInboundHandlerAdapter {
 
     private static final Logger log = LoggerFactory.getLogger(TCPServerHandler.class.getSimpleName());
 
-    private HandlerMapping handlerMapping;
+    private final HandlerMapping handlerMapping;
 
-    private HandlerInterceptor interceptor;
+    private final HandlerInterceptor interceptor;
 
-    private SessionManager sessionManager;
+    private final SessionManager sessionManager;
 
-    private SessionListener sessionListener;
+    private final SessionListener sessionListener;
 
     public TCPServerHandler(HandlerMapping handlerMapping,
                             HandlerInterceptor interceptor,
diff --git a/src/main/java/io/github/yezhihao/netmc/codec/DelimiterBasedFrameDecoder.java b/src/main/java/io/github/yezhihao/netmc/codec/DelimiterBasedFrameDecoder.java
index 36baeae..1aa7b59 100644
--- a/src/main/java/io/github/yezhihao/netmc/codec/DelimiterBasedFrameDecoder.java
+++ b/src/main/java/io/github/yezhihao/netmc/codec/DelimiterBasedFrameDecoder.java
@@ -40,7 +40,7 @@ public class DelimiterBasedFrameDecoder extends ByteToMessageDecoder {
         }
     }
 
-    protected Object decode(ChannelHandlerContext ctx, ByteBuf buffer) throws Exception {
+    protected Object decode(ChannelHandlerContext ctx, ByteBuf buffer) {
         // Try all delimiters and choose the delimiter which yields the shortest frame.
         int minFrameLength = Integer.MAX_VALUE;
         Delimiter minDelim = null;
diff --git a/src/main/java/io/github/yezhihao/netmc/codec/LengthFieldAndDelimiterFrameDecoder.java b/src/main/java/io/github/yezhihao/netmc/codec/LengthFieldAndDelimiterFrameDecoder.java
index f43c300..df5320d 100644
--- a/src/main/java/io/github/yezhihao/netmc/codec/LengthFieldAndDelimiterFrameDecoder.java
+++ b/src/main/java/io/github/yezhihao/netmc/codec/LengthFieldAndDelimiterFrameDecoder.java
@@ -100,7 +100,7 @@ public class LengthFieldAndDelimiterFrameDecoder extends DelimiterBasedFrameDeco
         throw new CorruptedFrameException("Adjusted frame length (" + frameLength + ") is less than initialBytesToStrip: " + initialBytesToStrip);
     }
 
-    protected Object decode(ChannelHandlerContext ctx, ByteBuf in) throws Exception {
+    protected Object decode(ChannelHandlerContext ctx, ByteBuf in) {
         if (in.readableBytes() < this.lengthFieldEndOffset) {
             return null;
         } else {
diff --git a/src/main/java/io/github/yezhihao/netmc/codec/MessageDecoderWrapper.java b/src/main/java/io/github/yezhihao/netmc/codec/MessageDecoderWrapper.java
index a43539f..967be35 100644
--- a/src/main/java/io/github/yezhihao/netmc/codec/MessageDecoderWrapper.java
+++ b/src/main/java/io/github/yezhihao/netmc/codec/MessageDecoderWrapper.java
@@ -16,7 +16,7 @@ import io.netty.handler.codec.DecoderException;
 @ChannelHandler.Sharable
 public class MessageDecoderWrapper extends ChannelInboundHandlerAdapter {
 
-    private MessageDecoder decoder;
+    private final MessageDecoder decoder;
 
     public MessageDecoderWrapper(MessageDecoder decoder) {
         this.decoder = decoder;
diff --git a/src/main/java/io/github/yezhihao/netmc/codec/MessageEncoderWrapper.java b/src/main/java/io/github/yezhihao/netmc/codec/MessageEncoderWrapper.java
index 28614f9..78b9813 100644
--- a/src/main/java/io/github/yezhihao/netmc/codec/MessageEncoderWrapper.java
+++ b/src/main/java/io/github/yezhihao/netmc/codec/MessageEncoderWrapper.java
@@ -17,7 +17,7 @@ import io.netty.handler.codec.EncoderException;
 @ChannelHandler.Sharable
 public class MessageEncoderWrapper extends ChannelOutboundHandlerAdapter {
 
-    private MessageEncoder encoder;
+    private final MessageEncoder encoder;
 
     public MessageEncoderWrapper(MessageEncoder encoder) {
         this.encoder = encoder;
diff --git a/src/main/java/io/github/yezhihao/netmc/core/AbstractHandlerMapping.java b/src/main/java/io/github/yezhihao/netmc/core/AbstractHandlerMapping.java
index 260338e..42aef77 100644
--- a/src/main/java/io/github/yezhihao/netmc/core/AbstractHandlerMapping.java
+++ b/src/main/java/io/github/yezhihao/netmc/core/AbstractHandlerMapping.java
@@ -17,7 +17,7 @@ import java.util.Map;
  */
 public abstract class AbstractHandlerMapping implements HandlerMapping {
 
-    private final Map<Object, Handler> handlerMap = new HashMap(60);
+    private final Map<Object, Handler> handlerMap = new HashMap<>(64);
 
     /**
      * 将Endpoint中被@Mapping标记的方法注册到映射表
@@ -25,8 +25,6 @@ public abstract class AbstractHandlerMapping implements HandlerMapping {
     protected synchronized void registerHandlers(Object bean) {
         Class<?> beanClass = bean.getClass();
         Method[] methods = beanClass.getDeclaredMethods();
-        if (methods == null)
-            return;
 
         for (Method method : methods) {
 
diff --git a/src/main/java/io/github/yezhihao/netmc/core/handler/AsyncBatchHandler.java b/src/main/java/io/github/yezhihao/netmc/core/handler/AsyncBatchHandler.java
index e023c71..767569f 100644
--- a/src/main/java/io/github/yezhihao/netmc/core/handler/AsyncBatchHandler.java
+++ b/src/main/java/io/github/yezhihao/netmc/core/handler/AsyncBatchHandler.java
@@ -23,17 +23,17 @@ public class AsyncBatchHandler extends Handler {
 
     private static final Logger log = LoggerFactory.getLogger(AsyncBatchHandler.class.getSimpleName());
 
-    private ConcurrentLinkedQueue<Message> queue;
+    private final ConcurrentLinkedQueue<Message> queue;
 
-    private ThreadPoolExecutor executor;
+    private final ThreadPoolExecutor executor;
 
-    private int poolSize;
+    private final int poolSize;
 
-    private int maxElements;
+    private final int maxElements;
 
-    private int maxWait;
+    private final int maxWait;
 
-    private int warningLines;
+    private final int warningLines;
 
     public AsyncBatchHandler(Object actionClass, Method actionMethod, String desc, int poolSize, int maxElements, int maxWait) {
         super(actionClass, actionMethod, desc);
@@ -50,8 +50,7 @@ public class AsyncBatchHandler extends Handler {
         this.warningLines = maxElements * poolSize * 50;
 
         this.queue = new ConcurrentLinkedQueue();
-        this.executor = new ThreadPoolExecutor(this.poolSize, this.poolSize, 1000L, TimeUnit.MILLISECONDS, new LinkedBlockingQueue<>(400),
-                new BasicThreadFactory.Builder().daemon(true).namingPattern(actionMethod.getName() + "-pool-%d").build());
+        this.executor = new ThreadPoolExecutor(this.poolSize, this.poolSize, 1000L, TimeUnit.MILLISECONDS, new LinkedBlockingQueue<>(400), new BasicThreadFactory.Builder().daemon(true).namingPattern(actionMethod.getName() + "-pool-%d").build());
 
         for (int i = 0; i < poolSize; i++) {
             boolean master = i == 0;
@@ -65,7 +64,7 @@ public class AsyncBatchHandler extends Handler {
         }
     }
 
-    public Message invoke(Message request, Session session) {
+    public <T extends Message> T invoke(T request, Session session) {
         queue.offer(request);
         return null;
     }
diff --git a/src/main/java/io/github/yezhihao/netmc/core/handler/Handler.java b/src/main/java/io/github/yezhihao/netmc/core/handler/Handler.java
index b8e2119..4e493df 100644
--- a/src/main/java/io/github/yezhihao/netmc/core/handler/Handler.java
+++ b/src/main/java/io/github/yezhihao/netmc/core/handler/Handler.java
@@ -34,7 +34,7 @@ public abstract class Handler {
         try {
             for (int i = 0; i < types.length; i++) {
                 Type type = types[i];
-                Class clazz;
+                Class<?> clazz;
                 if (type instanceof ParameterizedTypeImpl)
                     clazz = (Class<?>) ((ParameterizedTypeImpl) type).getActualTypeArguments()[0];
                 else
diff --git a/src/main/java/io/github/yezhihao/netmc/core/handler/SimpleHandler.java b/src/main/java/io/github/yezhihao/netmc/core/handler/SimpleHandler.java
index 7b0c106..c89e7bc 100644
--- a/src/main/java/io/github/yezhihao/netmc/core/handler/SimpleHandler.java
+++ b/src/main/java/io/github/yezhihao/netmc/core/handler/SimpleHandler.java
@@ -16,7 +16,7 @@ public class SimpleHandler extends Handler {
         super(actionClass, actionMethod, desc);
     }
 
-    public Message invoke(Message request, Session session) throws Exception {
+    public <T extends Message> T invoke(T request, Session session) throws Exception {
         return super.invoke(request, session);
     }
 }
\ No newline at end of file
diff --git a/src/main/java/io/github/yezhihao/netmc/util/ClassUtils.java b/src/main/java/io/github/yezhihao/netmc/util/ClassUtils.java
index 6cf28e7..424b4a1 100644
--- a/src/main/java/io/github/yezhihao/netmc/util/ClassUtils.java
+++ b/src/main/java/io/github/yezhihao/netmc/util/ClassUtils.java
@@ -8,7 +8,6 @@ import java.lang.annotation.Annotation;
 import java.net.JarURLConnection;
 import java.net.URL;
 import java.util.Enumeration;
-import java.util.Iterator;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.jar.JarEntry;
@@ -24,17 +23,12 @@ public class ClassUtils {
 
     public static List<Class<?>> getClassList(String packageName, Class<? extends Annotation> annotationClass) {
         List<Class<?>> classList = getClassList(packageName);
-        Iterator<Class<?>> iterator = classList.iterator();
-        while (iterator.hasNext()) {
-            Class<?> next = iterator.next();
-            if (!next.isAnnotationPresent(annotationClass))
-                iterator.remove();
-        }
+        classList.removeIf(next -> !next.isAnnotationPresent(annotationClass));
         return classList;
     }
 
     public static List<Class<?>> getClassList(String packageName) {
-        List<Class<?>> classList = new LinkedList();
+        List<Class<?>> classList = new LinkedList<>();
         String path = packageName.replace(".", "/");
         try {
             Enumeration<URL> urls = ClassUtils.getClassLoader().getResources(path);