Smack API Tutorial

Version: Smack 3.1.0 Beta
Smack is a Java XMPP library. You can create your own GTalk with this.
Digested from: http://www.javaprogrammingforums.com/java-tips-tutorials/551-how-write-simple-xmpp-jabber-client-using-smack-api.html

package jabberhelloworld;

import java.util.*;
import java.io.*;

import java.util.logging.Level;
import java.util.logging.Logger;
import org.jivesoftware.smack.Chat;
import org.jivesoftware.smack.ConnectionConfiguration;
import org.jivesoftware.smack.MessageListener;
import org.jivesoftware.smack.Roster;
import org.jivesoftware.smack.RosterEntry;
import org.jivesoftware.smack.SASLAuthentication;
import org.jivesoftware.smack.XMPPConnection;
import org.jivesoftware.smack.XMPPException;
import org.jivesoftware.smack.packet.Message;

public class Main implements MessageListener {

    XMPPConnection connection;

    public void login(String userName, String password) throws XMPPException {
        ConnectionConfiguration config = new ConnectionConfiguration("jabber.org", 5222, "jabber.org");
        connection = new XMPPConnection(config);

        connection.connect();
        SASLAuthentication.supportSASLMechanism("PLAIN", 0);
        connection.login(userName, password);
    }

    public void sendMessage(String message, String to) throws XMPPException {
        Chat chat = connection.getChatManager().createChat(to, this);
        chat.sendMessage(message);
    }

    public void displayBuddyList() {
        Roster roster = connection.getRoster();
        Collection<RosterEntry> entries = roster.getEntries();

        System.out.println("\n\n" + entries.size() + " buddy(ies):");
        for (RosterEntry r : entries) {
            System.out.println(r.getUser());
        }
    }

    public void disconnect() {
        connection.disconnect();
    }

    public void processMessage(Chat chat, Message message) {
        if (message.getType() == Message.Type.chat) {
            System.out.println(chat.getParticipant() + " says: " + message.getBody());
            try {
                chat.sendMessage(message.getBody() + " echo");
            } catch (XMPPException ex) {
                Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
            }
        }
    }

    public static void main(String args[]) throws XMPPException, IOException {
        // declare variables
        Main c = new Main();
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String msg;


        // turn on the enhanced debugger
        XMPPConnection.DEBUG_ENABLED = true;


        // Enter your login information here
        c.login("yourusername", "yourpassword");

        c.displayBuddyList();

        System.out.println("-----");

        System.out.println("Who do you want to talk to? - Type contacts full email address:");
        String talkTo = br.readLine();

        System.out.println("-----");
        System.out.println("All messages will be sent to " + talkTo);
        System.out.println("Enter your message in the console:");
        System.out.println("-----\n");

        while (!(msg = br.readLine()).equals("bye")) {
            c.sendMessage(msg, talkTo);
        }

        c.disconnect();
        System.exit(0);
    }
}