The server stop response. dead lock?

[sishen]

In my application,  i use mina 1.1 version.

Now i do some perfermance test.  Below is my test case.

loop (50) {
    client send message to server. (500 client one time).
    sleep 1s.
}

And  in the executing,  the server stop response. It just hang.  However,
sometimes it passed the test.

I sniff the network using tcpdump.  And i found that the packet is received
by the server machine, but no log output in the code decode part.
So I think it even don't go to the doDecode step. It's very strange, and i
don't know the reason.

Thank you for you advice. Below is the related code.

The code of server side:

public class BIIServer {
   private static final int port = 12345;
   private static BIIServerSessionHandler handler = new
BIIServerSessionHandler();

   public static void main(String[] args) throws Exception
   {
       try {
           Executor executor = Executors.newCachedThreadPool();
           SocketAcceptor acceptor = new
SocketAcceptor(Runtime.getRuntime().availableProcessors(),
executor);
           ExecutorThreadModel model = ExecutorThreadModel.getInstance
("BIIServer");
           model.setExecutor(executor);
           acceptor.getFilterChain().addLast("codec", new
ProtocolCodecFilter(new BIProtocolCodecFactory(true)));
           acceptor.getFilterChain().addLast("threadpool", new
ExecutorFilter(executor));
           SocketAcceptorConfig config = new SocketAcceptorConfig();
           config.setReuseAddress(true);
           acceptor.bind(new InetSocketAddress(port), handler, config);
           System.out.println("Server now listening on port: " + port);
       } catch (Exception ex) {
           ex.printStackTrace();
       }
   }
}

The code of client side:

   public UIDMessage orderUID(OrderUIDMessage message) {
       IoSession session;
       Object lock = new Object();
       for ( ; ; ) {
           try {
               ConnectFuture future = connector.connect(new
InetSocketAddress(host, port), handler, cfg);
               future.join();
               session = future.getSession();
               session.setAttribute("lock", lock);
               break;
           } catch (RuntimeIOException ex) {
           } catch (InterruptedException e) {
           }
       }
       session.write(message);
       synchronized (lock) {
           try {
               while (session.getAttachment() == null) {
                   lock.wait();                    <-   I use this to
ensure i receive the result message.  But due to the problem, it was made to
wait indefinitely.
               }
           } catch (InterruptedException ex) {
               ex.printStackTrace();
           }
       }
       UIDMessage UID = (UIDMessage)session.removeAttribute("");
       sessionMap.put(UID.getUid(), session);
       return UID;
   }