Swing VS. Sockets!

Question

Hi Swing Programmers!
I need an urgent help please. I'm doing a Peer to Peer program, but i have a problem with the Swing thread I guess. When I run the two windows (Cleint & Server), then I click the Connect button at the Client window, it connects and everything goes alright, and I can see my connection status in the Server window, but not at the Client window. Just when I click connect, the Client window freez & hangs. The Server side works alright, he can even type messages, but they are not sent to the Client. But the wiered thing, just when the Server hits the Disconnect button, the Client window goes back to the normal state, and prints all the Server messages!
Can anyone help me with that? Find the 2 files below, note that you have to pass the local & remote port when running the program. As:
java ClientSide port1 port2
java ServerSide port2 port1
Thanks.
// CLIENT
import java.io.*;
import java.net.*;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class ClientSide extends JFrame implements ActionListener
     private JLabel title;
     private JTextArea MessageArea;
     private JScrollPane Scroll_MsgArea;
     private JTextArea Input;
     private JScrollPane Scroll_Input;
     private JButton Connect;
     private JButton Disconnect;
     private JButton Send;
     private String message;
     private static String temp_local;
     private static String temp_remote;
     private static int local;
     private static int remote;
     private ServerSocket server;
     private Socket connection;
     private ObjectInputStream input;
     private ObjectOutputStream output;
     public ClientSide ()     
          super("Peer to Peer Socket Program");
          guiLayout customLayout = new guiLayout();
          Container c= getContentPane();
          c.setLayout(customLayout);
          title= new JLabel("Welcome!");
          c.add(title);
          MessageArea= new JTextArea();
          MessageArea.setEnabled(false);
          c.add(MessageArea);
          Scroll_MsgArea= new JScrollPane();
          //c.add(Scroll_MsgArea);
          //c.add(new JScrollPane(MessageArea));
          Input= new JTextArea();
          c.add(Input);
          Input.setEnabled(false);
          Scroll_Input= new JScrollPane();
          //c.add(Scroll_Input);
          Send= new JButton("Send");
          c.add(Send);
          Send.setEnabled(false);
          Connect= new JButton("Connect");
          c.add(Connect);
          Disconnect= new JButton("Disconnect");
          c.add(Disconnect);
          Disconnect.setEnabled(false);
          Connect.addActionListener(this);
          Send.addActionListener(this);
          Disconnect.addActionListener(this);
MessageArea.setText("\nClick Connect to start a communication channel");
     public void Client(int remote)
     try
     while(true)
          MessageArea.append("\nAttempting to connect...");
     connection= new Socket("139.182.139.102", remote);
MessageArea.append("\nConnected to: " + connection.getInetAddress().getHostAddress());
Input.setEnabled(true);
     //IO Streams
     output= new ObjectOutputStream(connection.getOutputStream());
               output.flush();
     input= new ObjectInputStream(connection.getInputStream());
          MessageArea.append("\nI/O Streams Received");
     Disconnect.setEnabled(true);
     //Process Connection
     Input.setEnabled(true);
               do {
                    try {
                         message= (String) input.readObject();
                         MessageArea.append("\n>>" + message);
                         MessageArea.setCaretPosition(MessageArea.getText().length());
     catch(ClassNotFoundException cnf){MessageArea.append("\nUnknown Input");}
while( !message.equals("\nUnknown Input"));
     catch(IOException io)
               MessageArea.append("\nConnection Terminated");
               Disconnect.setEnabled(false);
               Send.setEnabled(false);
               Connect.setEnabled(false);
     public void actionPerformed(ActionEvent e)
          if(e.getActionCommand() == "Connect")
                    Connect.setEnabled(false);
                    Client(remote);
          if(e.getActionCommand()== "Send")
               Send();
          if(e.getActionCommand() == "Disconnect")
               Disconnect();
     public void Send()
          try {
               output.writeObject("\n>> " + Input.getText());
               MessageArea.append("\n>> " + Input.getText());
               output.flush();
               Input.setText("");
          catch(IOException io){MessageArea.append("\nError Writing Data");}     
public void Disconnect()
          try{
               MessageArea.append("\n +-+-+ TERMINATED +-+-+");
               Input.setEnabled(false);
               output.close();
               input.close();
               connection.close();
               Disconnect.setEnabled(false);
               Send.setEnabled(false);
          catch(IOException io){MessageArea.append("\nError Writing Data");}     
     public static void main(String args[])
          ClientSide win= new ClientSide ();
          win.pack();
          win.show();
          temp_local= args[0];
          temp_remote= args[1];
          local= Integer.parseInt(temp_local);
          remote= Integer.parseInt(temp_remote);
          win.setDefaultCloseOperation(EXIT_ON_CLOSE);
//GUI stuff
class guiLayout implements LayoutManager {
public guiLayout() {
public void addLayoutComponent(String name, Component comp) {}
public void removeLayoutComponent(Component comp) {}
public Dimension preferredLayoutSize(Container parent) {
Dimension dim = new Dimension(0, 0);
Insets insets = parent.getInsets();
dim.width = 342 + insets.left + insets.right;
dim.height = 420 + insets.top + insets.bottom;
return dim;
public Dimension minimumLayoutSize(Container parent) {
Dimension dim = new Dimension(0, 0);
return dim;
public void layoutContainer(Container parent) {
Insets insets = parent.getInsets();
Component c;
c = parent.getComponent(0);
if (c.isVisible()) {c.setBounds(insets.left+80,insets.top+16,176,24);}
c = parent.getComponent(1);
if (c.isVisible()) {c.setBounds(insets.left+40,insets.top+48,264,200);}
c = parent.getComponent(2);
if (c.isVisible()) {c.setBounds(insets.left+40,insets.top+256,192,48);}
c = parent.getComponent(3);
if (c.isVisible()) {c.setBounds(insets.left+232,insets.top+264,72,32);}
c = parent.getComponent(4);
if (c.isVisible()) {c.setBounds(insets.left+40,insets.top+336,85,24);}
c = parent.getComponent(5);
if (c.isVisible()) {c.setBounds(insets.left+232,insets.top+336,85,24);}
//SERVER
/* A P2P program, developed by ELHARITH ELRUFAIE, for the CSCI 660 lab.
SERVER SIDE */
import java.io.*;
import java.net.*;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
// SERVER SIDE
public class ServerSide extends JFrame implements ActionListener
     private JLabel title;
     private JTextArea MessageArea;
     private JScrollPane Scroll_MsgArea;
     private JTextArea Input;
     private JScrollPane Scroll_Input;
     private JButton Disconnect;
     private JButton Send;
     private String message;
     private static String temp_local;
     private static String temp_remote;
     private static int local;
     private static int remote;
     private ServerSocket server;
     private Socket connection;
     private ObjectInputStream input;
     private ObjectOutputStream output;
     public ServerSide()     
          super("Peer to Peer Socket Program");
          guiLayout customLayout = new guiLayout();
          Container c= getContentPane();
          c.setLayout(customLayout);
          title= new JLabel("Welcome!");
          c.add(title);
          MessageArea= new JTextArea();
          MessageArea.setEnabled(false);
          c.add(MessageArea);
          Scroll_MsgArea= new JScrollPane();
          //c.add(Scroll_MsgArea);
          //c.add(new JScrollPane(MessageArea));
          Input= new JTextArea();
          c.add(Input);
          Input.setEnabled(false);
          Scroll_Input= new JScrollPane();
          //c.add(Scroll_Input);
          Send= new JButton("Send");
          c.add(Send);
          Send.setEnabled(false);
          Disconnect= new JButton("Disconnect");
          c.add(Disconnect);
          Disconnect.setEnabled(false);
          Send.addActionListener(this);
          Disconnect.addActionListener(this);
     public void Server(int local)
     try{
          server= new ServerSocket(local);
while(true)
          //Receiving the Connection
          MessageArea.setText("\nWaiting for Connection...");
          connection= server.accept();
          MessageArea.append("\nReceiving connection from " + connection.getInetAddress().getHostAddress());
          //IO Streams
          output= new ObjectOutputStream(connection.getOutputStream());
          output.flush();
          input= new ObjectInputStream(connection.getInputStream());
          MessageArea.append("\nI/O Streams Received\n");
          //Process the Connection()
          Input.setEnabled(true);
          String message= "==> Connected Successfully...";     
          output.writeObject(message);
          output.flush();
          MessageArea.append(message);
          Send.setEnabled(true);
          Disconnect.setEnabled(true);
          do {
          try {
                    message= (String) input.readObject();
                    MessageArea.append("\n" + message);
          catch(ClassNotFoundException cnf)
                    {MessageArea.append("\nUnknown Input");}
               output.writeObject(Input.getText());
               output.flush();     
while( !message.equals("\nUSER>> TERMINATED"));
     catch(IOException iof) {MessageArea.append("\nDisconnected Sucessfully");}     
     public void actionPerformed(ActionEvent e)
          if(e.getActionCommand()== "Send")
               Send();
          if(e.getActionCommand() == "Disconnect")
               Disconnect();
     public void Send()
          try {
               output.writeObject("\n>> " + Input.getText());
               MessageArea.append("\n>> " + Input.getText());
               output.flush();
               Input.setText("");
          catch(IOException io){MessageArea.append("\nError Writing Data");}     
     public void Disconnect()
          try{
               MessageArea.append("\n +-+-+ TERMINATED +-+-+");
               Input.setEnabled(false);
               output.close();
               input.close();
               connection.close();
               Disconnect.setEnabled(false);
               Send.setEnabled(false);
          catch(IOException io){MessageArea.append("\nError Writing Data");}     
     public static void main(String args[])
          ServerSide win= new ServerSide();
          win.pack();
          win.show();
          temp_local= args[0];
          temp_remote= args[1];
          local= Integer.parseInt(temp_local);
          remote= Integer.parseInt(temp_remote);
          win.Server(local);
          win.setDefaultCloseOperation(EXIT_ON_CLOSE);
//GUI stuff
class guiLayout implements LayoutManager {
public guiLayout() {
public void addLayoutComponent(String name, Component comp) {}
public void removeLayoutComponent(Component comp) {}
public Dimension preferredLayoutSize(Container parent) {
Dimension dim = new Dimension(0, 0);
Insets insets = parent.getInsets();
dim.width = 342 + insets.left + insets.right;
dim.height = 420 + insets.top + insets.bottom;
return dim;
public Dimension minimumLayoutSize(Container parent) {
Dimension dim = new Dimension(0, 0);
return dim;
public void layoutContainer(Container parent) {
Insets insets = parent.getInsets();
Component c;
c = parent.getComponent(0);
if (c.isVisible()) {c.setBounds(insets.left+80,insets.top+16,176,24);}
c = parent.getComponent(1);
if (c.isVisible()) {c.setBounds(insets.left+40,insets.top+48,264,200);}
c = parent.getComponent(2);
if (c.isVisible()) {c.setBounds(insets.left+40,insets.top+256,192,48);}
c = parent.getComponent(3);
if (c.isVisible()) {c.setBounds(insets.left+232,insets.top+264,72,32);}
c = parent.getComponent(4);
if (c.isVisible()) {c.setBounds(insets.left+232,insets.top+336,85,24);}

Answer 1

After running your programs, I got a clearer idea of what was wrong. AFAIK, the following are wrong with your programs:
1. Your calling of "win.Server(local);" in ServerSide.java after some Swing components in your program have been realised is not thread safe. Put the call to that method in the event-dispatching thread of the program.
Also in your programs, you shouldn't have called the "setDefaultCloseOperation" method after the "pack" mthod. This is also not thread safe.
2. The do-while statement in the "Client" method of ClientSide.java causes your program to get stuck in its event-dispatching thread after it (your program) calls the "Client" method from one of the event handlers. That's why ClientSide is even unable to repaint itself when necessary after getting stuck. Perhaps you should move any method that may stall the event-dispatching thread to a seperate thread.