哲学家就餐问题--死锁的思考

代码：

package j2se;
class kuaizi{
    String name;
    boolean Enable = true;

    public kuaizi(String name){
        this.name = name;
    }

    public synchronized void pickup(){
        this.Enable =false;
    }

    public synchronized void putdown(){
        this.Enable =true;
        this.notifyAll();
    }

}
class Philosopher extends Thread{
    String name;
    kuaizi left;
    kuaizi right;
    public Philosopher(String name, kuaizi l, kuaizi r){
        this.name = name;
        left = l;
        right = r;
    }

    public void run(){
        if(left.Enable){
            left.pickup();
        }
        else{
            while(!left.Enable){
                try{
                    System.out.println(name + " 在等待 "+left.name);
                    Thread.sleep(500);
                }catch (InterruptedException e){
                    e.printStackTrace();
                }
            }
        }

        System.out.println(name + " 眼明手快，以迅雷不及掩耳之势一把抓起 "+left.name);

        try{
            Thread.sleep(500);
        }catch (InterruptedException e){
            e.printStackTrace();
        }

        if(right.Enable){
            right.pickup();
        }else{
            while (!left.Enable){
                try{
                    System.out.println(name + "在等待 "+right.name);
                    Thread.sleep(500);
                }catch (InterruptedException e){
                    e.printStackTrace();
                }
            }

        }

        System.out.println(name + " 眼明手快，以迅雷不及掩耳之势一把抓起 "+right.name);
        System.out.println(name + " 左右开弓，狼吞虎咽起来");

        try{
            Thread.sleep(2000);
        }catch (InterruptedException e){
            e.printStackTrace();
        }
        System.out.println(name + " 酒足饭饱，打了个饱嗝，心满意足的放下了 "+left.name+" 和 " +right.name);
        left.putdown();
        right.putdown();
    }
}

public class Eat1{
    public static void main(String args[]){
        kuaizi k1 = new kuaizi("筷子1号");
        kuaizi k2 = new kuaizi("筷子2号");
        kuaizi k3 = new kuaizi("筷子3号");
        kuaizi k4 = new kuaizi("筷子4号");
        kuaizi k5 = new kuaizi("筷子5号");
        Philosopher p1 = new Philosopher("老大", k1, k2);
        Philosopher p2 = new Philosopher("老二", k2, k3);
        Philosopher p3 = new Philosopher("老三", k3, k4);
        Philosopher p4 = new Philosopher("老四", k4, k5);
        Philosopher p5 = new Philosopher("老幺", k5, k1);
        p1.start();
        p2.start();
        p3.start();
        p4.start();
        p5.start();
    }
}