Operator timer RxJava

RxOperatorTimer.java

public class RxOperatorTimer {
    public static void main(String[] args) throws InterruptedException {
        CountDownLatch countDownLatch = new CountDownLatch(1);
        Observable.timer(1000 * 2, TimeUnit.MILLISECONDS)
                .subscribe(new Observer<Long>() {
                    @Override
                    public void onSubscribe(Disposable d) {
                        System.out.println("onSubscribe");
                    }

                    @Override
                    public void onNext(Long count) {
                        System.out.println("onNext " + count);
                    }

                    @Override
                    public void onError(Throwable e) {
                        System.out.println("onError");
                    }

                    @Override
                    public void onComplete() {
                        System.out.println("onComplete");
                        countDownLatch.countDown();
                    }
                });
        countDownLatch.await();
    }
}