@Override public void start(Future<Void> future) throws Exception { StompClient.create(vertx) .connect( ar -> { if (ar.failed()) { future.fail(ar.cause()); return; } final StompClientConnection connection = ar.result(); connection .receivedFrameHandler(frame -> System.out.println("Client receiving:\n" + frame)) .writingFrameHandler(frame -> System.out.println("Client sending:\n" + frame)) .subscribe( "/queue", FRAMES::add, frame -> { if (!future.isComplete()) { future.complete(); } }); }); }