public void timed() {
        boolean captured = false;
        try {
            captured = lock.tryLock(2, TimeUnit.SECONDS);
        } catch(InterruptedException e) {
            throw new RuntimeException(e);
        }
        try {
            System.out.println("tryLock(2. TimeUnit SECONDS):" +captured);
        } finally {
            if(captured)
                lock.unlock();
        }
    }