WebSucket.java

final WebSocketContainer container = ContainerProvider.getWebSocketContainer();
final URI securedEndpointURL = new URI("wss://echo.websocket.org");

container.connectToServer(new Endpoint() {
  @Override
  public void onOpen(Session session, EndpointConfig config) {
    System.out.println("Connected!!!!!");
  }
//}, ClientEndpointConfig.Builder.create().build(), securedEndpointURL);
}, securedEndpointURL);  // ah !!! :-) 

// better than java-websocket project