The basic form of a WebSocket using the org.eclipse.jetty.websocket.api.WebSocketListener for incoming events.

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package examples.echo;

import org.eclipse.jetty.websocket.api.Session;
import org.eclipse.jetty.websocket.api.WebSocketListener;

/**
 * Example EchoSocket using Listener.
 */
public class ListenerEchoSocket implements WebSocketListener
{
    private Session outbound;

    @Override
    public void onWebSocketBinary(byte[] payload, int offset, int len)
    {
        /* only interested in text messages */
    }

    @Override
    public void onWebSocketClose(int statusCode, String reason)
    {
        this.outbound = null;
    }

    @Override
    public void onWebSocketConnect(Session session)
    {
        this.outbound = session;
    }

    @Override
    public void onWebSocketError(Throwable cause)
    {
        cause.printStackTrace(System.err);
    }

    @Override
    public void onWebSocketText(String message)
    {
        if ((outbound != null) && (outbound.isOpen()))
        {
            System.out.printf("Echoing back message [%s]%n",message);
            // echo the message back
            outbound.getRemote().sendString(message,null);
        }
    }
}

This is by far the most basic and best performing (speed and memory wise) WebSocket implementation you can create. If the listener is too much work for you, you can instead opt for the WebSocketAdapter