Chat System: ConnectException: Connection timed out: connect

Question

Hi There,
I am developing a chat system as part of a University project.
To explain what I have implemented:
I have three java classes;
1. Chat Server class which is constantly listening for incoming socket connection on a particular socket:
while (true)
Socket client = server.accept ();
System.out.println ("Accepted from " + client.getInetAddress ());
ChatHandler c = new ChatHandler (client);
c.start ();
2. Chat Handler class uses a thread for each client to handle multiple clients:
public ChatHandler (Socket s) throws IOException
this.s = s;
i = new DataInputStream (new BufferedInputStream (s.getInputStream ()));
o = new DataOutputStream (new BufferedOutputStream (s.getOutputStream ()));
public void run ()
try
handlers.addElement (this);
while (true)
String msg = i.readUTF ();
broadcast (msg);
catch (IOException ex)
ex.printStackTrace ();
finally
handlers.removeElement (this);
try
s.close ();
catch (IOException ex)
ex.printStackTrace();
protected static void broadcast (String message)
synchronized (handlers)
Enumeration e = handlers.elements ();
while (e.hasMoreElements ())
ChatHandler c = (ChatHandler) e.nextElement ();
try
synchronized (c.o)
c.o.writeUTF (message);
c.o.flush ();
catch (IOException ex)
c.stop ();
3. Chat Client class which has a simple GUI and sends messages to the server to be broadcasted to all other clients on the same socket port:
public ChatClient (String title, InputStream i, OutputStream o)
super (title);
this.i = new DataInputStream (new BufferedInputStream (i));
this.o = new DataOutputStream (new BufferedOutputStream (o));
setLayout (new BorderLayout ());
add ("Center", output = new TextArea ());
output.setEditable (false);
add ("South", input = new TextField ());
pack ();
show ();
input.requestFocus ();
listener = new Thread (this);
listener.start ();
public void run ()
try
while (true)
String line = i.readUTF ();
output.appendText (line + "\n");
catch (IOException ex)
ex.printStackTrace ();
finally
listener = null;
input.hide ();
validate ();
try
o.close ();
catch (IOException ex)
ex.printStackTrace ();
public boolean handleEvent (Event e)
if ((e.target == input) && (e.id == Event.ACTION_EVENT)) {
try {
o.writeUTF ((String) e.arg);
o.flush ();
} catch (IOException ex) {
ex.printStackTrace();
listener.stop ();
input.setText ("");
return true;
} else if ((e.target == this) && (e.id == Event.WINDOW_DESTROY)) {
if (listener != null)
listener.stop ();
hide ();
return true;
return super.handleEvent (e);
public static void main (String args[]) throws IOException
Socket s = new Socket ("192.168.2.3",4449);
new ChatClient ("Chat test", s.getInputStream (), s.getOutputStream ());
On testing this simple app on my local host I have launched several instances of ChatClient and they interact perfectly between each other.
Although when i test this app by launching ChatClient on another machine (using a wi-fi network connection at home), on the other machine that tries to connect to the hosting server (my machine) i get a "connection timed out" on the chatClient machine.
I have added the port and ip addresses in concern to the exceptions to by-pass the firewall but i am still getting the timeout.
Any suggestions?
Thanks!

Answer 1

Format your code with [ code ] tag pair.
If you are a young university student I don't understand why current your code uses so many of
too-too-too old APIs including deprecated ones.
For example, DataInput/OutputStream should never be used for text I/Os because they aren't
always reliable.
Use Writers and Readers in modern Java programming
Here's a simple and standard chat program example:
(A few of obsolete APIs from your code remain here, but they are no problem.
Tested both on localhost and a LAN.)
/* ChatServer.java */
import java.io.*;
import java.util.*;
import java.net.*;
public class ChatServer{
  ServerSocket server;
  public ChatServer(){
    try{
      server = new ServerSocket(4449);
      while (true){
        Socket client = server.accept();
        System.out.println("Accepted from " + client.getInetAddress());
        ChatHandler c = new ChatHandler(client);
        c.start ();
    catch (IOException e){
      e.printStackTrace();
  public static void main(String[] args){
    new ChatServer();
class ChatHandler extends Thread{
  static Vector<ChatHandler> handlers = new Vector<ChatHandler>();
  Socket s;
  BufferedReader i;
  PrintWriter o;
  public ChatHandler(Socket s) throws IOException{
    this.s = s;
    i = new BufferedReader(new InputStreamReader(s.getInputStream()));
    o = new PrintWriter
     (new BufferedWriter(new OutputStreamWriter(s.getOutputStream())));
  public void run(){
    try{
      handlers.addElement(this);
      while (true){
        String msg = i.readLine();
        broadcast(msg);
    catch (IOException ex){
      ex.printStackTrace();
    finally{
      handlers.removeElement(this);
      try{
        s.close();
      catch (IOException e){
        e.printStackTrace();
  protected static void broadcast(String message){
    synchronized (handlers){
      Enumeration e = handlers.elements();
      while (e.hasMoreElements()){
        ChatHandler c = (ChatHandler)(e.nextElement());
        synchronized (c.o){
          c.o.println(message);
          c.o.flush();
/* ChatClient.java */
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.net.*;
import java.io.*;
public class ChatClient extends JFrame implements Runnable{
  Socket socket;
  JTextArea output;
  JTextField input;
  BufferedReader i;
  PrintWriter o;
  Thread listener;
  JButton endButton;
  public ChatClient (String title, Socket s){
    super(title);
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    socket = s;
    try{
      i = new BufferedReader(new InputStreamReader(s.getInputStream()));
      o = new PrintWriter
       (new BufferedWriter(new OutputStreamWriter(s.getOutputStream())));
    catch (IOException ie){
      ie.printStackTrace();
    Container con = getContentPane();
    con.add (output = new JTextArea(), BorderLayout.CENTER);
    output.setEditable(false);
    con.add(input = new JTextField(), BorderLayout.SOUTH);
    con.add(endButton = new JButton("END"), BorderLayout.NORTH);
    input.addActionListener(new ActionListener(){
      public void actionPerformed(ActionEvent ae){
        o.println(input.getText());
        o.flush();
        input.setText("");
    endButton.addActionListener(new ActionListener(){
      public void actionPerformed(ActionEvent ev){
        try{
          socket.close();
        catch (IOException ie){
          ie.printStackTrace();
        System.exit(0);
    setBounds(50, 50, 500, 500);
    setVisible(true);
    input.requestFocusInWindow();
    listener = new Thread(this);
    listener.start();
  public void run(){
    try{
      while (true){
        String line = i.readLine();
        output.append(line + "\n");
    catch (IOException ex){
      ex.printStackTrace();
    finally{
      o.close();
  public static void main (String args[]) throws IOException{
    Socket sock = null;
    String addr = "127.0.0.1";
    if (args.length > 0){
      addr = args[0];
    sock = new Socket(addr, 4449);
    new ChatClient("Chat Client", sock);
}