...A WebSocket server by itself doesn't do anything except establish socket connections though HTTP. After that it's up to your subclass to add purpose. The org.java_websocket.client.WebSocketClient abstract class can connect to valid WebSocket servers. The constructor expects a valid ws:// or wss:// URI to connect to. Important events onOpen, onClose, onMessage and onError get fired throughout the life of the WebSocketClient, and must be implemented in your subclass.