Websocket Jakarta EE Sample Application. A very simple HTML5 Websocket application,server-side used Java Jakarta EE for developing it. Using Java Jakarta EE to develop Websocket application is very simple and the plaform make's it easy by just annotating plain old pojo with @ServerEndpoint(value="/simpleEndpoint") and you can call Websocket callback functions by using annotations (@OnMessage,@OnOpen,@OnClose,@OnError). With Jakarta EE you just need to annotate your bean and you're good to go. Enjoy!!.