1 /* 2 下面的程序会出现下面的情况，当Thread-0， Thread-1， Thread-2都被wait的时候，可能会同时苏醒 3     Thread-0 put 4     Thread-1 put 5     Thread-2 put 6     Thread-3 get//在此处，Thread-3拿到锁之后，将所有的等待的线程唤醒，才有了下面的输出 7     Thread-2 put 8     Thread-1 put 9     Thread-0 put10 */11 12 13    虽然多个线程会同时苏醒，但是只有一个能获得cpu的执行权！14    总之，同步中执行的只能是一个，但是存活的不一定就是一个！15 16 17 class DuckD{18     public void put(){19         20         synchronized(DuckD.class){21           22               System.out.println(Thread.currentThread().getName()+" put");23               try{24                  DuckD.class.wait();//Thread-0， Thread-1， Thread-2可能会同时在这里苏醒！25               }catch(InterruptedException e){26                  27               }28               //........29         }30     }31     32     public void get(){33         34         synchronized(DuckD.class){35 36                 DuckD.class.notifyAll();37               System.out.println(Thread.currentThread().getName()+" get");38               try{39                  DuckD.class.wait();40               }catch(InterruptedException e){41                  42               }         43         }44     }45 }46 47 class ProduceD implements Runnable{48     DuckD dk;49     ProduceD(DuckD dk){50        this.dk=dk;51     }52     public void run(){53        while(true)54          dk.put();55     }    56 }57 58 class ConsumeD implements Runnable{59     DuckD dk;60     ConsumeD(DuckD dk){61        this.dk=dk;62     }63     public void run(){64         while(true)65           dk.get();66     }    67 }68 69 class Test{70    public static void main(String[] args){71        DuckD dk=new DuckD();72        Thread t1=new Thread(new ProduceD(dk));73        Thread t2=new Thread(new ProduceD(dk));74        Thread t3=new Thread(new ProduceD(dk));75        Thread t4=new Thread(new ConsumeD(dk));76        77        t1.start();78        t2.start();79        t3.start();80        t4.start();81    }82 }