diff --git a/ListHead.java b/ListHead.java
new file mode 100644
index 0000000..bbee752
--- /dev/null
+++ b/ListHead.java
@@ -0,0 +1,23 @@
+package  a6;
+
+public class ListHead {
+
+    public ListHead next;
+    public ListHead prev;
+
+    public void del() {
+
+    }
+
+    public void delInit() {
+
+    }
+
+    public void addTail(ListHead newNode) {
+
+    }
+
+    public boolean empty() {
+        return false;
+    }
+}
diff --git a/SysUtils.java b/SysUtils.java
index 69f165a..a6a283b 100644
--- a/SysUtils.java
+++ b/SysUtils.java
@@ -2,4 +2,7 @@ package  a6;
 
 public class SysUtils {
 
+    public static void test() {
+        System.out.println("test");
+    }
 }
diff --git a/TcpListener.java b/TcpListener.java
new file mode 100644
index 0000000..9dce277
--- /dev/null
+++ b/TcpListener.java
@@ -0,0 +1,66 @@
+package  a6;
+
+import io.netty.bootstrap.ServerBootstrap;
+
+import io.netty.channel.ChannelFuture;
+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.socket.SocketChannel;
+import io.netty.channel.socket.nio.NioServerSocketChannel;
+
+public class TcpListener {
+
+    public int bindPort = 0;
+    public String bindAddress;
+
+    public void TcpListener(int max_client_cnt) {
+
+    }
+
+    public void open() {
+        EventLoopGroup bossGroup = new NioEventLoopGroup();
+        EventLoopGroup workerGroup = new NioEventLoopGroup();
+
+        try {
+            ServerBootstrap b = new ServerBootstrap();
+            b.group(bossGroup, workerGroup)
+             .channel(NioServerSocketChannel.class)
+             .childHandler(new ChannelInitializer<SocketChannel>() {
+                 @Override
+                 public void initChannel(SocketChannel ch) throws Exception {
+                     //                     ch.pipeline().addLast(new DiscardServerHandler());
+                 }
+             })
+             .option(ChannelOption.SO_BACKLOG, 128)
+             .childOption(ChannelOption.SO_KEEPALIVE, true);
+
+            ChannelFuture f = b.bind(this.bindPort).sync();
+            f.channel().closeFuture().sync();
+
+        } catch(Exception e) {
+
+        } finally {
+            workerGroup.shutdownGracefully();
+            bossGroup.shutdownGracefully();
+        }
+    }
+
+    public void close() {
+
+    }
+
+    public boolean isActive() {
+        return false;
+    }
+
+    public boolean sendClientMsg() {
+        return false;
+    }
+
+    public void broadcastMsg() {
+
+    }
+
+}
diff --git a/Timer.java b/Timer.java
new file mode 100644
index 0000000..fb7b79f
--- /dev/null
+++ b/Timer.java
@@ -0,0 +1,80 @@
+package a6;
+
+public class Timer {
+
+    public class TimerList
+    {
+        private ListHead entry = new ListHead();
+        private ListHead attachEntry;
+        private int timerType = 0;
+        private int milli_seconds = 0;
+        private long expires = 0;
+
+        private ITimerFunc timerFunc;
+        private ITimerAfterFunc timerAfterFunc;
+        private XParams param;
+    }
+
+    @FunctionalInterface
+    public interface ITimerFunc
+    {
+        public void OnTimer(XParams param);
+    }
+
+    @FunctionalInterface
+    public interface ITimerAfterFunc
+    {
+        public void OnTimerAfter(XParams param);
+    }
+
+    private int freeTimerNum = 0;
+    private ListHead freeTimer = new ListHead();
+
+    public void init() {
+
+    }
+
+    public void unInit() {
+
+    }
+
+    public void update() {
+
+    }
+
+    public TimerList addDeadLineTimer(int expire_time, XParams param, ITimerFunc timer_func) {
+        return null;
+    }
+
+    public TimerList addDeadLineTimer(int expire_time, XParams param, ITimerFunc timer_func,
+                                 ITimerAfterFunc timer_after_func) {
+        return null;
+    }
+
+    public void modifyTimer(TimerList timer_list, int expire_time) {
+
+    }
+
+    public void deleteTimer(TimerList timer_list) {
+        if (timer_list.timerAfterFunc != null) {
+            timer_list.timerAfterFunc.OnTimerAfter(timer_list.param);
+        }
+        detachTimer(timer_list);
+        if (timer_list.attachEntry != null && !timer_list.attachEntry.empty()) {
+            timer_list.attachEntry.del();
+        }
+        addToFreeList(timer_list);
+    }
+
+    public void detachTimer(TimerList timer_list) {
+        if (timer_list.entry != null && !timer_list.entry.empty()) {
+            timer_list.entry.delInit();
+        }
+    }
+
+    private void addToFreeList(TimerList timer_list) {
+        freeTimer.addTail(timer_list.entry);
+        ++freeTimerNum;
+    }
+
+}
diff --git a/TimerAttacher.java b/TimerAttacher.java
new file mode 100644
index 0000000..568ab39
--- /dev/null
+++ b/TimerAttacher.java
@@ -0,0 +1,13 @@
+package  a6;
+
+public class TimerAttacher {
+
+    public void clearTimer() {
+
+    }
+
+    public void free() {
+        clearTimer();
+    }
+
+}
diff --git a/XParams.java b/XParams.java
new file mode 100644
index 0000000..127f912
--- /dev/null
+++ b/XParams.java
@@ -0,0 +1,14 @@
+package  a6;
+
+public class XParams {
+
+    public XValue sender = new XValue();
+    public XValue param1 = new XValue();
+    public XValue param2 = new XValue();
+    public XValue param3 = new XValue();
+
+    public static XParams newXParams() {
+        return new XParams();
+    }
+
+}
diff --git a/XValue.java b/XValue.java
new file mode 100644
index 0000000..c9ba5cd
--- /dev/null
+++ b/XValue.java
@@ -0,0 +1,5 @@
+package  a6;
+
+public class XValue {
+
+}