并发数值增加范例

并发情况下数据增加的一个范例

package com.example.demo;

import java.util.ArrayList;

public class TestThread implements Runnable {
    static  Integer i = 0;
    static TestThread instance = new TestThread();
    public static void main(String[] args) throws InterruptedException {
          Thread t1 = new Thread(new TestThread());
          Thread t2 = new Thread(new TestThread());
          t1.start();
          t2.start();
          t1.join();
          t2.join();
        System.out.println(i);

    }

    @Override
    public void run() {
        for(int j=0;j<100000;j++){
            synchronized (instance){
                i++;
            }

        }
    }

}