Example of reentrant lock thread waiting to wake up

1.synchronized

package juc.one;

/**
 *  First step   Create a resource class , Define properties and operation methods 
 *  The second step   Judge   work   notice 
 *  The third step   Create multiple threads , Call the operation method of the resource class 
 *  Step four   Prevent false wake-up problems 
 */


// First step   Create a resource class , Define properties and operation methods 
class Share {
    // Initial value 
    private  int number = 0;
    //+1 Methods 
    public synchronized void incr() throws InterruptedException {
        // The second step   Judge   work   notice 
       while (number != 0){ // Judge number Is the value 0, If not 0, wait for 
            this.wait();// Prevent false awakening , To call in a loop 
        }
        // If number The value is 0, Just +1 operation 
        number++;
        System.out.println(Thread.currentThread().getName()+" :: "+number);
        // Notify other threads 
        this.notifyAll();
    }

    //-1 Methods 
    public synchronized void decr() throws InterruptedException {
        // Judge 
        while(number != 1){
            this.wait();
        }
        // work 
        number--;
        System.out.println(Thread.currentThread().getName()+" :: "+number);
        // Notify other threads 
        this.notifyAll();
    }
}
public class ThreadDemo1 {
    // The third step   Create multiple threads , Call the operation method of the resource class 
    public static void main(String[] args) {
        Share share = new Share();
        // Create thread 
        new Thread(()->{
            for(int i = 1; i<=10; i++){
                try {
                    share.incr();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        },"AA").start();

        new Thread(()->{
            for(int i = 1; i<=10; i++){
                try {
                    share.decr();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        },"BB").start();

        new Thread(()->{
            for(int i = 1; i<=10; i++){
                try {
                    share.incr();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        },"CC").start();

        new Thread(()->{
            for(int i = 1; i<=10; i++){
                try {
                    share.decr();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        },"DD").start();
    }
}

2.ReentrantLock

package juc.two;

import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;

class Share {
    private int number = 0;

    // establish lock
    private Lock lock = new ReentrantLock();
    private Condition condition = lock.newCondition();

    //+1
    public void incr() throws InterruptedException {
        // locked 
        lock.lock();
        try {
            // Judge 
            while (number != 0){
                condition.await();
            }
            // work 
            number++;
            System.out.println(Thread.currentThread().getName()+" :: "+number);
            // notice 
            condition.signalAll();
        }finally {
            // Unlock 
            lock.unlock();
        }
    }

    //-1
    public void decr() throws InterruptedException {
        lock.lock();
        try{
            // Judge 
            while (number != 1){
                condition.await();
            }
            number--;
            System.out.println(Thread.currentThread().getName()+" :: "+number);
            condition.signalAll();
        }finally {
            lock.unlock();
        }
    }
}

public class ThreadDemo2 {
    public static void main(String[] args) {
        Share share = new Share();
        // Create thread 
        new Thread(()->{
            for(int i = 1; i<=10; i++){
                try {
                    share.incr();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        },"AA").start();

        new Thread(()->{
            for(int i = 1; i<=10; i++){
                try {
                    share.decr();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        },"BB").start();

        new Thread(()->{
            for(int i = 1; i<=10; i++){
                try {
                    share.incr();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        },"CC").start();

        new Thread(()->{
            for(int i = 1; i<=10; i++){
                try {
                    share.decr();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        },"DD").start();
    }
}