//Say fps = 30 i.e. you must generate a frame every 1/30 seconds which is about 33 ms)

ScheduledThreadPoolExecutor pool = new ScheduledThreadPoolExecutor(1); //threadpool of size 1

//in your loop
pool.scheduleAtFixedRate(<runnable task>, 0, 33, TimeUnit.MILLISECONDS);

You can of course cancel the pool or do an orderly shutdown whenever required depending on your loop conditions. Since the pool only has one thread, if a task overshoots its running time, the next task will be delayed and the rate of generation of frames would slow down affecting the game.