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Thread: Java Messenger Program?

  1. #1
    Join Date
    Jul 2009
    Thanked 0 Times in 0 Posts

    Default Java Messenger Program?

    Well here's basically what I'm trying to accomplish.
    I'm trying to write a program that when run on two computers, both can send messages and the messages will appear on each one of the computers.
    Basically, it's like aim.

    Here's what I have so far, but this only works on the running computer, doesn't really allow other computers to connect to mine.
    I'm wondering what I need to do to make this work so multiple computers can connect with each other.
    Also I wasn't sure were to post this, I don't think this is much of a newbie project, but it isn't that advanced

    Lesson: All About Sockets (The Java™ Tutorials > Custom Networking)

    import java.io.ObjectInputStream;
    import java.io.ObjectOutputStream;
    import java.net.ServerSocket;
    import java.net.Socket;
    import java.util.ArrayList;
    import java.util.Iterator;
    public class MusicServer {
    ArrayList<ObjectOutputStream> clientOutputStreams;
    public static void main(String[] args) {
        new MusicServer().go();
    public class ClientHandler implements Runnable{
    ObjectInputStream in;
    Socket clientSocket;
    public ClientHandler(Socket socket) {
    try {
    clientSocket = socket;
    in = new ObjectInputStream(clientSocket.getInputStream());
    } catch (Exception e) {
    }//close constructor
    public void run(){
        Object o2 = null;
        Object o1 = null;
        try {
            while((o1 = in.readObject())!=null) {
            o2 = in.readObject();
            System.out.println("Read two objects");
        } catch (Exception e) {
            // TODO: handle exception
    public void go() {
    clientOutputStreams = new ArrayList<ObjectOutputStream>();
    try {
        ServerSocket serverSock = new ServerSocket(4444);
        while(true) {
            Socket clientSocket = serverSock.accept();
        ObjectOutputStream out = new ObjectOutputStream(clientSocket.getOutputStream());
        Thread t = new Thread(new ClientHandler(clientSocket));
        System.out.println("Got a connection");
    } catch (Exception e) {
        // TODO: handle exception
    public void tellEveryone(ObjectOutputStream one, Object two) {
    Iterator it = clientOutputStreams.iterator();
    while(it.hasNext()) {
    try {
    ObjectOutputStream out = (ObjectOutputStream)it.next();
    } catch (Exception e) {
        // TODO: handle exception

  2. #2
    Junior Member
    Join Date
    Sep 2009
    Thanked 3 Times in 3 Posts

    Default Re: Java Messenger Program?

    I have done this using RMI instead of socket programming.If you have problem with normal java RMI, then use the Spring
    RMI samples available in to the net.

    Good Luck

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