This snippet connects to a server and port of your choice and reads input. It does not handle output: you will have to do it yourself. An example will be provided in this description.

What I like about this snippet is that it can easily be modified into an event driven irc lib. I will probably be using it as a base for the client I am working on.

Here is an example of how to send outputs using the main method:

public static void main(String[] args) { IRCConnection connection = new IRCConnection("irc.sxci.net", 6667); try { connection.connect(); Scanner in = new Scanner(System.in); while (in.hasNextLine()) { connection.sendRaw(in.nextLine()); if (!connection.isConnected()) { break; } } } catch (IOException e) { System.out.println("Ooops!\n" + e); } }

Image (green is output):

import java.io.*;
import java.net.Socket;
import java.util.*;

/**
 * @author Aion
 *         Created on 08/10/12
 */
public class IRCConnection {

    private final int port;
    private final String server;

    private Socket socket;

    private Timer readTimer;
    private Timer eventProcessorTimer;

    private LinkedList<IRCEvent> eventQueue = new LinkedList<>();

    public IRCConnection(String server) {
        this(server, 6667);
    }

    public IRCConnection(String server, int port) {
        this.server = server;
        this.port = port;
    }

    public void connect() throws IOException {
        if (isConnected()) {
            System.out.println("We're already connected!");
            return;
        }
        socket = new Socket(server, port);

        readTimer = new Timer();
        readTimer.schedule(new TimerTask() {
            @Override
            public void run() {
                read();
            }
        }, 0, 200);

        eventProcessorTimer = new Timer();
        eventProcessorTimer.schedule(new TimerTask() {
            @Override
            public void run() {
                processEvent();
            }
        }, 0, 200);
    }

    public void disconnect() throws IOException {
        if (!isConnected()) {
            System.out.println("We're not connected!");
            return;
        }
        socket.close();
        socket = null;
        readTimer.cancel();
        eventProcessorTimer.cancel();
    }

    public boolean isConnected() {
        return socket != null && socket.isConnected();
    }

    private void processEvent() {
        synchronized (eventQueue) {
            if (eventQueue.isEmpty()) {
                try {
                    eventQueue.wait();
                } catch (InterruptedException e) {
                    System.out.println("Event queue interrupted\n " + e);
                }
            }
            IRCEvent event = eventQueue.poll();
            String prefix = event.getPrefix();
            String command = event.getCommand();
            String param = event.getParameter();

            String input = String.format("Prefix: %s Command: %s Param: %s", prefix, command, param);
            System.out.println(input);
        }
    }

    private void read() {
        if (isConnected()) {
            try {
                BufferedReader br = new BufferedReader(new InputStreamReader(socket.getInputStream()));
                String input = br.readLine();
                while ((input = br.readLine()) != null) {
                    synchronized (eventQueue) {
                        eventQueue.push(new IRCEvent(input));
                        eventQueue.notifyAll();
                    }
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    public void sendRaw(String output) throws IOException {
        if (!isConnected()) {
            System.out.println("We're not connected!");
            return;
        }
        BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(socket.getOutputStream()));
        writer.write(output + "\r\n");
        writer.flush();
    }

    public static class IRCEvent extends EventObject {

        protected final String prefix;
        protected final String command;
        protected final String param;

        public IRCEvent(String raw) {
            super(raw);

            String prefix = "";
            String command = "";
            String param = "";

            String[] split = raw.split(" ", 3);
            int index = 0;

            if (raw.startsWith(":")) {
                prefix = split[index++].substring(1);
            }

            command = split[index++];
            param = split[index++];

            this.prefix = prefix;
            this.command = command;
            this.param = param;
        }

        public String getCommand() {
            return command;
        }

        public String getParameter() {
            return param;
        }

        public String getPrefix() {
            return prefix;
        }

    }

}