1. Principle

Lock synchronization lock

Signal() and await() of condition

2. Code examples

package com.thread;

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

public class TasksTestLock extends Thread {
    private static Lock lock = new ReentrantLock();
    private static Condition condition = lock.newCondition();
    private static int num = 1;
    private int id;

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


    @Override
    public void run() {
        while (num <= 12) {

            lock.lock();

            System.out.println("Thread" + id + " num:" + num);
            num++;

            condition.signal();
            try {
                condition.await();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }

            lock.unlock();

        }
    }


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

        ExecutorService exec = Executors.newFixedThreadPool(3);

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

        exec.shutdown();

    }
}

3. Output results