public void useTimeUnit() {
		System.out
				.println("-----------Use TTimeUnit.SECONDS.sleep()-------------");
		System.out.println("Sleep for 5 seconds.");
		try {
			TimeUnit.SECONDS.sleep(5); // Same as Thread.sleep(5000);
			System.out.println("woke up.");
		} catch (InterruptedException e) {
			e.printStackTrace();
		}
	}