java多线程，锁的问题

Question

下面这段代码中，为什么会打印出奇数值并且退出，但是将注释去掉，程序就不会退出呢？求大神解答啊

package com.zy.test.lock;

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

public class AtomicityTest implements Runnable
{
private int i = 0;
public synchronized int getValue()
{
return i;
}

public synchronized void evenIncrement()
{
    i++;

// i++;
}

public void run()
{
    while (true)
    {
        evenIncrement();
    }
}

public static void main(String[] args)
{
    ExecutorService service = Executors.newCachedThreadPool();
    AtomicityTest test = new AtomicityTest();
    service.execute(test);
    while (true)
    {
        int val = test.getValue();
        if (val % 2 != 0)
        {
            System.out.println(val);
            System.exit(0);
        }
    }
}

}

Answer 1

http://blog.csdn.net/conquer0715/article/details/50133821
https://my.oschina.net/shyloveliyi/blog/470154