本例是閱讀Think in Java中相應章節後，自己實際寫了一下自己的實現

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;
/*
假設一個學生，日出而作日落而息
*/
class Student
{
    private boolean Awake=false;
    public synchronized void wakeUp()
    {
        Awake=true;
        System.out.println(
 
"WakeUp!");
        notifyAll();    //notifyAll()寫在這裏！1.臨界區 2.已經做了一些改變
    }
    public synchronized void sleep()
    {
        Awake=false;
        System.out.println("Sleep!");
        notifyAll();    //同上
    }
    public  synchronized void waitForSleep() throws InterruptedException {
        while(Awake!=false
 
) wait(); //等待寫在這裏！1.臨界區 2.等待外界改變的條件
    }
    public  synchronized void waitForAwake() throws InterruptedException{
        while(Awake!=true) wait();  //同上
    }
    public boolean isAwake() {
        return Awake;
    }
}
class SunRise implements Runnable
{//日出
    Student student=null;
    public SunRise(Student student)
    {
        
 
this.student=student;
    }
    @Override public void run()
    {
        try {
            while (!Thread.interrupted()) {
                student.waitForSleep(); //先等待環境變化
                TimeUnit.MILLISECONDS.sleep(100);
                student.wakeUp();       //環境已變化，起床！
                System.out.println("End Awake");
            }

        }catch (InterruptedException e)
        {
            e.printStackTrace();
        }

    }
}
class SunFall implements Runnable
{
    Student student=null;
    public SunFall(Student student)
    {
        this.student=student;
    }
    @Override public void run()
    {
        try{
            while (!Thread.interrupted()) {
                student.waitForAwake(); //先等待環境變化
                TimeUnit.MILLISECONDS.sleep(100);
                student.sleep();        //環境已變化，睡覺！
                System.out.println("End Sleep");
            }

        }catch (InterruptedException e)
        {
            e.printStackTrace();
        }

    }
}
public class Main{
    public static void main(String[]args)
    {
        Student me=new Student();
        SunRise sunRise=new SunRise(me);
        SunFall sunFall=new SunFall(me);
        ExecutorService service= Executors.newCachedThreadPool();
        service.execute(sunRise);
        service.execute(sunFall); 
    }
}

輸出是

WakeUp!
End Awake
Sleep!
End Sleep

的不停循環。

應該算成功了吧。

JAVA wait()和notifyAll()實現線程間通訊