Socket communication failure between Java applet and C++ application

Question

I have a java applet that connects to a C++ application via Java's ServerSocket and Socket objects. THe C++ application is using the Winsock 2 API. The applet and application are running on an NT workstation (SP 6) and using IE (5.5) For a very simple C++ test applications the communictions work fine. Once more code gets added to the C++ application the portion of the socket that C++ listens to seems to close. Upon performing a recv call the return value is a zero. Microsoft insists this is a sign the Java side has shut down the socket. The Java applet can still receive messages from the C++ app but C++ cannot receive responses from the Java side. Java throws no exceptions and an explicit check of the socket shows no errors. Again, what puzzles me is that it works for simple C++ applications. Are there any known conflicts between Java and C++ in this regard?
I have inlcuded the basic java code segments below.
/ run Method.
  * This method is called by the Thread.start() method. This
  * method is required for the implementation of the Runnable interface
  * This method sets up the server side socket communication and
  * contiuously loops looking for requests from a external
  * socket.
  * @author Chris Duke
  public void run(){
     // create socket connections
     boolean success = false;
     try {
         cServerSocket = new ServerSocket(cPortID);
         System.out.println("Waiting for client to connect...");
         cClientSocket = cServerSocket.accept();
         System.out.println("Client connected");
         // Create a stream to read from the client
         cInStream = new BufferedReader(new InputStreamReader(
           cClientSocket.getInputStream()));
         // Create a stream to write to the client       
         cOutStream = new PrintWriter(
           cClientSocket.getOutputStream(), true);
         success = true;
     }catch (IOException e) {
         System.out.println("CommSocket:Run - Socket Exception(1) " + e);
         success = false;
     // if the socket was successfully created, keep the thread running
     while (success){
         try{
            // check socket to see if it is still available for reading
            if (cInStream != null && cInStream.ready()){
                // check for an incoming message
                String message = ReceiveMessage();
                // Send message to listeners
                Event(message);
            if (cInStream == null){
                success = false;
                System.out.println("CommSocket:Run - shutdown");
         }catch (IOException e){
            System.out.println("CommSocket:Run - Socket not ready exception");
            break;
// SendMessage method -
  *  Sends a text message to a connected listener through port specified by portID
  * @author Chris Duke
  * @param  String message - This will be the message sent out through the server
  * socket's port specified by portID.
   public void SendMessage(String message){
      cOutStream.println(message);
      if (cOutStream.checkError() == true)
        System.out.println("SendMessage : Flush = Error");
      else{
        System.out.println("SendMessage : Flush - No Error");
   }

Answer 1

a very simple C++ test applications the communictions work fine. Once more code gets added to the C++ application the portion of the socket that C++ listens to seems to close.
This quite strongly implicates the extra code in the C++ App. The firstly thing I would try would be telnet. Try connecting to both versions of the C++ Application and manually reproducing a proper exchange.
a recv call the return value is a zero. Microsoft insists this is a sign the Java side has shut down the socket.
A correct implementation of recv should return the number of bytes received, or -1 for an error. A zero return indicates no bytes received not a socket closed/error. This sounds like FUD to me.
Are there any known conflicts between Java and C++ in this regard?
I can see no obvious faults, though the code is incomplete, I don't think it's an sockets implementation issue, at either end, it sounds more likely to be a protocol/handshaking bug in the C++ App.