public void comsume(){
		synchronized (this) {
			while (objs.size() == 0) {
				System.out.println("It is empty.");
				try {
					wait();
				} catch (InterruptedException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
			Object obj = objs.removeLast();
			System.out.println("Consumer:" + obj);
			notify();
		}
	}