synchronous錯誤使用__java多線程

i++後對象變化了，所以會出現錯誤的結果。

package com.brendan.cn.concurrent;import java.net.InetAddress;/*************************************************************** * Created by martin on 2017/9/29. ***************************************************************/public class IntegerLock {    static Integer i = 0;    public  static  class  AddThread extends Thread {        @Override        public void run() {            for(int k=0;k<10000;k++){                synchronized (i) {                    i++;                }            }        }    }    public static void main(String[] args) throws InterruptedException {        Thread t1 = new AddThread();        Thread t2 = new AddThread();        t1.start();        t2.start();        t1.join();        t2.join();        System.out.println(i);    }}