主要功能是兩個線程操作一個變量，一個讓它+1，一個讓它-1然后交替輸出

public?class?Res?{
	private?boolean?flag?=?true;
	private?int?x?=?1;

	public?synchronized?void?print1()?{
		if?(!flag)?{
			try?{
				this.wait();
			}?catch?(InterruptedException?e)?{
				e.printStackTrace();
			}
		}
		System.out.println(x++);
		flag?=?false;
		this.notify();

	}

	public?synchronized?void?print2()?{

		if?(flag)?{
		}
		try?{
			this.wait();
		}?catch?(InterruptedException?e)?{
			e.printStackTrace();
		}

		System.out.println(x--);
		flag?=?true;
		this.notify();
	}

}

public?class?PrintOne?implements?Runnable{
	private?Res?r;
	public?PrintOne(Res?r){
		this.r=r;
	}
public?void?run(){
	while(true){
		r.print1();
	}
}
}

public?class?PrintTwo?implements?Runnable{
	private?Res?r;
	public?PrintTwo(Res?r){
		this.r=r;
	}
public?void?run(){
	while(true){
		r.print2();
	}
}
}

public?class?Test?{
	public?static?void?main(String[]?args)?{
		Res?r=new?Res();
		new?Thread(new?PrintOne(r)).start();
		new?Thread(new?PrintTwo(r)).start();
	}

}

運行結果就是輸出一個1，就停住了，哪里死鎖了還是全部等待了