1. Principle

Synchronized thread synchronization

Notify() calls up the thread

The wait() thread waits

2. Code examples

package com.thread;

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class TasksTestSync extends Thread {
    private static Integer num = 0;
    private int id;

    public TasksTestSync(int id) {
        this.id = id;
    }

    @Override
    public void run() {
        while (num < 12) {
            synchronized (TasksTestSync.class) {
                num = num + 1;
                System.out.println("thread_" + id + " num:" + num);

                TasksTestSync.class.notify();
                try {
                    TasksTestSync.class.wait();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }

            }
        }
    }

    public static void main(String[] args) {
        Thread thread0 = new TasksTestSync(0);
        Thread thread1 = new TasksTestSync(1);

        ExecutorService exec = Executors.newFixedThreadPool(3);

        exec.submit(thread0);
        exec.submit(thread1);

        exec.shutdown();

    }
}

3. Implementation results