Thread: Socket programming something gone wrong

Hi All,

I have this code in which i am attempting to broadcast messages to all clients connected.Currently i have a server and can support upto max of 10 clients.
When a client1 sends a message , the server intercepts it and sends an ACK to the calling client.Until the client recieves an ACK i want to stop this client from sending further messages.
On the server, once i send teh ACk to CLient1 i want to broadcast this msg to the n clients connected.
Currently i see that after 3 runs my code hangs on client and whatever msg i send from client is nvr getting printed.
If i run using a debugger on server i am able to get this working.Guess the issue is with threads.
Please help.

----------------------------------------------------------------------------
SERVER CODE
----------------------------------------------------------------------------

import java.io.*;
import java.lang.management.ThreadInfo;
import java.net.*;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
 
public class MultiThreadChatServer{
 
    // Declaration section:
    // declare a server socket and a client socket for the server
    // declare an input and an output stream
 
    static  Socket clientSocket = null;
    static  ServerSocket serverSocket = null;
 
    // This chat server can accept up to 10 clients' connections
    static  clientThread t[] = new clientThread[10];           
 
    public static void main(String args[]) {
 
	// The default port
 
	int port_number=2229;
 
 
	// Initialization section:
	// Try to open a server socket on port port_number (default 2222)
	// Note that we can't choose a port less than 1023 if we are not
	// privileged users (root)
 
        try {
	    serverSocket = new ServerSocket(port_number);
        }
        catch (IOException e)
	    {System.out.println(e);}
 
	// Create a socket object from the ServerSocket to listen and accept 
	// connections.
	// Open input and output streams for this socket will be created in 
	// client's thread since every client is served by the server in
	// an individual thread
 
	while(true){
	    try {
		clientSocket = serverSocket.accept();
		for(int i=0; i<=9; i++){
		    if(t[i]==null)
			{
			    (t[i] = new clientThread(clientSocket,t)).start();
			    break;
			}
		}
	    }
	    catch (IOException e) {
		System.out.println(e);}
	}
    }
} 
 
// This client thread opens the input and the output streams for a particular client,
// ask the client's name, informs all the clients currently connected to the 
// server about the fact that a new client has joined the chat room, 
// and as long as it receive data, echos that data back to all other clients.
// When the client leaves the chat room this thread informs also all the
// clients about that and terminates. 
 
class clientThread extends Thread{
 
    DataInputStream is = null;
    PrintStream os = null;
    Socket clientSocket = null;       
    clientThread t[]; 
 
    public clientThread(Socket clientSocket, clientThread[] t){
	this.clientSocket=clientSocket;
        this.t=t;
    }
 
    public void run() 
    {
	String line;
        String name;
        BlockingQueue<String> queue =new ArrayBlockingQueue<String>(200);
	try{
	    is = new DataInputStream(clientSocket.getInputStream());
	    os = new PrintStream(clientSocket.getOutputStream());
 
	    os.println("Enter your name.");
	    name = is.readLine();
	    t[0].os.println("ACK");
	    for(int i=0; i<=9; i++)
		if (t[i]!=null && t[i]==this)  
		    System.out.println("*** A new user "+name+" entered the service !!! ***" );
	    while (true) {
		line = is.readLine();
		try{
			if(line.startsWith("quit")) break; 
			queue.put(line);
			for(int i=0; i<=9; i++)
			    if (t[i]!=null && t[i]==this) {
			    	t[i].os.println("ACK");
			    }
 
 
 
                String item=null;
		for(int i=0; i<=9; i++)
		    if (t[i]!=null) {
		    	if(i==0)
		    		item=queue.take();
		    	t[i].os.println("<"+name+"> "+item); 
		    }
		}catch(InterruptedException w)
		{
			System.out.println("Interrupt");
		}
	    }
	    for(int i=0; i<=9; i++)
		if (t[i]!=null && t[i]!=this)  
		    System.out.println("*** The client "+name+" is leaving the service !!! ***" );
 
	    os.println("*** Bye "+name+" ***"); 
 
	    // Clean up:
	    // Set to null the current thread variable such that other client could
	    // be accepted by the server
 
	    for(int i=0; i<=9; i++)
		if (t[i]==this) t[i]=null;  
 
	    // close the output stream
	    // close the input stream
	    // close the socket
 
	    is.close();
	    os.close();
	    clientSocket.close();
	}
	catch(IOException e){};
    }
}

----------------------------------------------------------
CLIENT
----------------------------------------------------------

import java.io.*;
import java.lang.management.ManagementFactory;
import java.net.*;
 
public class MultiThreadChatClient implements Runnable{
 
    // Declaration section
    // clientClient: the client socket
    // os: the output stream
    // is: the input stream
 
    static Socket clientSocket = null;
    static PrintStream os = null;
    static DataInputStream is = null;
    static BufferedReader inputLine = null;
    static boolean closed = false;
    static boolean blocked = false;
    static int seqNo=0;
 
    public static void main(String[] args) {
 
	// The default port	
 
	int port_number=2229;
        String host="localhost";
 
	// Initialization section:
	// Try to open a socket on a given host and port
	// Try to open input and output streams
	try {
            clientSocket = new Socket(host, port_number);
            inputLine = new BufferedReader(new InputStreamReader(System.in));
            os = new PrintStream(clientSocket.getOutputStream());
            is = new DataInputStream(clientSocket.getInputStream());
        } catch (UnknownHostException e) {
            System.err.println("Don't know about host "+host);
        } catch (IOException e) {
            System.err.println("Couldn't get I/O for the connection to the host "+host);
        }
 
	// If everything has been initialized then we want to write some data
	// to the socket we have opened a connection to on port port_number 
 
        if (clientSocket != null && os != null && is != null) {
            try {
 
		// Create a thread to read from the server
 
                new Thread(new MultiThreadChatClient()).start();
 
		while (!closed ) {
				if(!blocked){
 
                    os.println(inputLine.readLine()+"^^"+ManagementFactory.getRuntimeMXBean().getName().split("@")[0]+"^^"+seqNo);
                    System.out.println("I AM HERE");
                    blocked=true;
                    seqNo++;
				}
 
                }
 
		// Clean up:
		// close the output stream
		// close the input stream
		// close the socket
 
		os.close();
		is.close();
		clientSocket.close();   
            } catch (IOException e) {
                System.err.println("IOException:  " + e);
            }
        }
    }           
 
    public void run() {		
	String responseLine;
 
	// Keep on reading from the socket till we receive the "Bye" from the server,
	// once we received that then we want to break.
	try{ 
	    while ((responseLine = is.readLine()) != null) {
	    	if(responseLine.equals("ACK")){
	    		blocked=false;
	    	}
	    	//System.out.println("blocked:"+blocked);
		System.out.println(responseLine);
 
		if (responseLine.indexOf("*** Bye") != -1) break;
	    }
            closed=true;
	} catch (IOException e) {
	    System.err.println("IOException:  " + e);
	}
    }
}