1、 Problem description

To print alternately two threads by program 0-100 Odd even number of

2、 Their thinking

Let thread 1 Wake up other threads after printing , Then get out of the lock , I go to sleep , Because it enters the sleep state, it will not compete with other threads for locks , There are only threads 2 Can get the lock , Threads 2 Execute... With the same logic , Wake up the thread 1 And give up the lock , I go to sleep .

Code

	private int count = 0;
    private final Object lock = new Object();
    public void turning() throws InterruptedException {
    
        Thread even = new Thread(() -> {
    
            while (count <= 100) {
    
                synchronized (lock) {
    
                    System.out.println(" even numbers : " + count++);
                    lock.notifyAll();
                    try {
    
                        //  If it's not over , Then release the current lock and sleep 
                        if (count <= 100) {
    
                            lock.wait();
                        }
                    } catch (InterruptedException e) {
    
                        e.printStackTrace();
                    }
                }
            }
        });
        Thread odd = new Thread(() -> {
    
            while (count <= 100) {
    
                synchronized (lock) {
    
                    System.out.println(" Odd number : " + count++);
                    lock.notifyAll();
                    try {
    
                        //  If it's not over , Then release the current lock and sleep 
                        if (count <= 100) {
    
                            lock.wait();
                        }
                    } catch (InterruptedException e) {
    
                        e.printStackTrace();
                    }
                }
            }
        });
        even.start();
        //  Make sure that even threads get the lock first 
        Thread.sleep(1);
        odd.start();
    }

public class TurningRunner implements Runnable {
    
    private  int count=0;
    private final  Object lock = new Object();
    @Override
    public void run() {
    
        while (count <= 100) {
    
            //  Get the lock 
            synchronized (lock) {
    
                //  Print when you get the lock 
                System.out.println(Thread.currentThread().getName() + ": " + count++);
                //  Wake up other threads 
                lock.notifyAll();
                try {
    
                    if (count <= 100) {
    
                        //  If the mission is not over , Then release the current lock and sleep 
                        lock.wait();
                    }
                } catch (InterruptedException e) {
    
                    e.printStackTrace();
                }
            }
        }
    }
}