AsyncSample.java

    @Override
    public void run() {
        ExecutorService executorService = Executors.newFixedThreadPool(10);

        while (true) {
            final long start = System.currentTimeMillis();
            for (final AsyncContext aync : rateWatchers) {
                executorService.submit(new Runnable() {
                    @Override
                    public void run() {
                        try {
                            PrintWriter writer = aync.getResponse().getWriter();
                            writer.println("Time: " + start);
                            writer.flush();
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                    }
                });
            }
            long timePassed = System.currentTimeMillis() - start;
            if (timePassed < 1000) try {
                Thread.sleep(1000-timePassed);
            } catch (InterruptedException e) {

            }
        }
    }