哲学家问题

//哲学家问题
//什么是死锁？
//比如两个相互占用对方所需的资源，但是都不释放自己的
//所以就形成了无限等待的现象
//死锁一旦产生没有外力帮助就永远存在，对程序产生严重影响
public class DeadLock extends Thread{
	protected Object tool;
	static Object fork1 = new Object();
	static Object fork2 = new Object();
	public DeadLock(Object obj){
		this.tool = obj;
		if(tool == fork1){
			this.setName("哲学家A");
		}
		if(tool == fork2){
			this.setName("哲学家B");
		}
	}
	@Override
	public void run(){
		if(tool == fork1){
			synchronized(fork1){
				try{
					Thread.sleep(500);
				}catch(Exception e){
					e.printStackTrace();
				}
				synchronized(fork2){
					System.out.println("哲学家A开始吃饭");
				}
			}
		}
		if(tool == fork2){
			synchronized(fork2){
				try{
					Thread.sleep(500);
				}catch(Exception e){
					e.printStackTrace();
				}
				synchronized(fork1){
					System.out.println("哲学家B开始吃饭");
				}
			}
		}
	}
	public static void main(String[] args) throws Exception{
		DeadLock A = new DeadLock(fork1);
		DeadLock B = new DeadLock(fork2);
		A.start();
		B.start();
		Thread.sleep(1000);
	}
}