关于notify 和notifyAll方法

 看这段程序
package org.arcie.simulator.test;public class NotifyTest implements Runnable {   
    
    private Wait wait;   
       
    public NotifyTest(Wait wait){   
        this.wait = wait;   
    }   
    public void run() {   
           
        wait.doSomthing();   
    }   
       
    public static void main(String [] args){   
        Wait wait = new Wait(4,"DAVID");   
        Thread  t1 = new Thread(new NotifyTest(wait));   
        Thread  t2 = new Thread(new NotifyTest(wait));   
        Thread  t3 = new Thread(new NotifyTest(wait));   
        Thread  t4 = new Thread(new NotifyTest(wait));   
  
        t1.start();  
        t2.start();
        t3.start();   
        t4.start();   
    }   
  
}  class Wait {   
    private int counter = 0;   
    private String name = null;   
    public Wait(int counter,String name){   
        this.counter = counter;   
        this.name = name;   
    }   
       
    public synchronized void doSomthing(){   
        int tempCounter = --counter;   
        if(tempCounter <= 0){   
            customizedNotifyAll();   
        }   
        else  
        {   
            while(tempCounter > 0){   
                try {   
                    System.out.println(Thread.currentThread().getName()+"-<"+name+tempCounter+">"+"will invoke WAIT()");   
                    --tempCounter;   
                    wait();   
                       
                       
                } catch (InterruptedException e) {   
                    e.printStackTrace();   
                    notifyAll();   
                }   
                System.out.println(Thread.currentThread().getName()+"-<"+name+tempCounter+">"+"has been ACTIVED");   
                
            }   
            customizedNotifyAll(); 
  
        }   
           
    }   
       
    public void customizedNotifyAll(){   
        notify(); //可以把这句换成notifyAll();  
        System.out.println(Thread.currentThread().getName()+"-<"+name+counter+">"+"::"+"INVOKED NOTIFYALL() AND FINISHED");   
    }   
  
} 问题：不是都说notify（） 方法是随机唤醒等待的线程吗？但为什么我运行的结果每次都是一样的呢？？
运行结果始终是：
Thread-0-<DAVID3>will invoke WAIT()
Thread-1-<DAVID2>will invoke WAIT()
Thread-2-<DAVID1>will invoke WAIT()
Thread-3-<DAVID0>::INVOKED NOTIFYALL() AND FINISHED
Thread-0-<DAVID2>has been ACTIVED
Thread-0-<DAVID2>will invoke WAIT()还有把public void customizedNotifyAll()方法里的notify()语句换成notifyAll(）语句，唤醒所有等待的线程，让这些线程去竞争同步资源，既然是竞争，按理说运行结果也应该是随机的才对啊，为什么我的运行结果每次又都是一样的呢？
结果如下：
Thread-0-<DAVID3>will invoke WAIT()
Thread-1-<DAVID2>will invoke WAIT()
Thread-2-<DAVID1>will invoke WAIT()
Thread-3-<DAVID0>::INVOKED NOTIFYALL() AND FINISHED
Thread-2-<DAVID0>has been ACTIVED
Thread-2-<DAVID0>::INVOKED NOTIFYALL() AND FINISHED
Thread-1-<DAVID1>has been ACTIVED
Thread-1-<DAVID1>will invoke WAIT()
Thread-0-<DAVID2>has been ACTIVED
Thread-0-<DAVID2>will invoke WAIT()