Code stops on readLine() method, doesnt resume!

Hi Experts,

I am building a simple client/server system in Java. In a nutshell, this is what happens:-

Server is loaded and waits for connections
Login Client is loaded, constructor builds GUI with username and password fields, a radio option button group, and a submit button.
Login Client connects to Server & starts a BufferedReader & BufferedWriter.
Login Client then calls a go() function inside the constructor including a readLine() method from the BufferedReader.
On submit, username, password, and label of chosen radio button is sent to the server.
Server authenticates user and sends back message to Login Client.
Login client reads message and depending on content either loads the client application class or refuses connection.

Currently the application is coded to support only one client.

My problem is, the code for the SeatLogin class appears to halt at the readLine() within the go method, and it doesnt move from there. It is within a do {} while(true) loop, which i think is supposed to continue executing. This kind of loop is used both on the Server and the Client Application class, and works just fine within these. However, it does not appear to work in my class.

SeatLogin go() method:-
  public void go() {
    System.out.println("user status is "+userStatus);
    try {
      do {
        System.out.println("No reason why you cant see me");
        String commandLine;
        String commandStr;
        String expectedOperator;

        System.out.println("But then things would make sense then");
        commandLine = br.readLine();
        System.out.println("they probably dont now");

        System.out.println("user status is "+userStatus);
        System.out.println("Command line recieved:"+commandLine);

        StringTokenizer st = new StringTokenizer(commandLine);
        commandStr = st.nextToken();
        expectedOperator = st.nextToken();

        if (commandStr.equals("bye-bye"))
          break;
        else {
          userStatus = Integer.parseInt(commandStr);
        }
        System.out.println(" user status is "+userStatus);

        if (userStatus == 0) {
          System.out.println("im waiting, user status is still "+userStatus);
        }
        if (userStatus == 1) {
          System.out.println("Thunderbirds are go");
          Block[] b = new Block[ 3 ];
          b[ 0 ] = new Block( 7, 7 );
          b[ 1 ] = new Block( 4, 4 );
          b[ 2 ] = new Block( 7, 7 );

          SeatClient s = new SeatClient( b, txtUsername.getText());      // Create.
          s.pack();  //Pack objects
          s.setVisible( true );  //Set GUI visible
          s.go();  //Run the code to interpret Server-sent commands


        }
        else if (userStatus == 2) {
          System.out.println("Thunderbird already here, sorry.");

        }
        else if (userStatus == 3) {
          System.out.println("Security Alert! Unauthorised User");

        }
      }
      while ( true );
      socket.close();
      System.out.println("Client network connection closed.");
      System.exit(1);
    }
    catch (IOException e) {
      System.out.println(e.toString());
      System.exit(1);
    }
  }

SeatClient go() method (very similar):-
  public void go() {
    try {
      do {
        String commandLine;      // From server e.g: 6D RESERVE SUSAN
        String seatStr;            // Seat e.g: 6D
        String commandStr;      // Command e.g: RESERVE
        String operatorStr;      // Operator e.g. SUSAN

        commandLine  = br.readLine();      // Command from server.
        System.out.println(
            systemOperator + " received: " + commandLine );
        StringTokenizer st = new StringTokenizer( commandLine );
        seatStr     = st.nextToken();
        if (seatStr.equals("bye-bye"))
          break;
        commandStr  = st.nextToken();
        operatorStr = st.nextToken();


        // Get button from hashtable and set its colour:
        Button b = (Button)( ht.get( seatStr ) );
        if ( commandStr.equals( "FREE" ) )
          b.setBackground( Color.lightGray );
        else if ( commandStr.equals( "RESERVE" ) ) {
          if ( operatorStr.equals( systemOperator ) )
            b.setBackground( Color.green );
          else
            b.setBackground( Color.red );
        }
        else if ( commandStr.equals( "ALLOCATE" ) )
          b.setBackground( Color.red );
      }

      while ( true );
      socket.close();
      System.out.println("Client network connection closed.");
      System.exit(1);
    }
    catch ( IOException e ) {
      System.out.println( e.toString() );
      System.exit( 1 );
    }
  }

Socket connection code (set up after UI is built elsewhere):-
    try {                  // Connect to server:
      socket = new Socket( "127.0.0.1", 6001 );
      br = new BufferedReader( new InputStreamReader(
          socket.getInputStream() ) );
      dos = new DataOutputStream( socket.getOutputStream() );
    }
    catch ( IOException e ) {
      System.out.println( e.getMessage() );
    }

What am i doing wrong!