NIO

public void run()
{
    try {
        while (keepRunning) {
            doSelection (selector);
        }
        serverSocketChannel.close();
        selector.close();
    } catch (Exception e) {
        logger.fatal ("Unexpected exception: ", e);
    }
}
protected void doSelection (Selector selector)
    throws IOException
{
    selector.select();
    if ( ! keepRunning) return;
    for (Iterator it = selector.selectedKeys().iterator(); it.hasNext();)
    {
        SelectionKey key = (SelectionKey) it.next();
        it.remove();
        if (key.isAcceptable()) {
            acceptNewConnection (key);
            continue;
        }
        Connection connection = (Connection) key.attachment();
        if (key.isWritable()) {
            connection.drainOutput();
            continue;
        }
        if (key.isReadable()) {
            connection.readInput();
            drainQueuedMessages (connection);
            continue;
        }
    }
}
protected void acceptNewConnection (SelectionKey serverKey)
    throws IOException
{
    ServerSocketChannel serverSocketChannel =
        (ServerSocketChannel) serverKey.channel();
    SocketChannel socketChannel =
        serverSocketChannel.accept();
    User user = new GenericUser (null);
    socketChannel.configureBlocking (false);
    SelectionKey key = socketChannel.register (
        serverKey.selector(), SelectionKey.OP_READ);
    Connection connection = new NIOConnection (this,
        user, getProtocol(), key);
    key.attach (connection);
    connection.startup();
}