何时删除线程堆栈内存？

Question

public class VolatileTest {
private static final Logger LOGGER = Logger.getLogger(VolatileTest.class.getName());

private static int MY_INT = 0;

public static void main(String[] args) {
    new ChangeListener().start();
    new ChangeMaker().start();
}

static class ChangeListener extends Thread {
    @Override
    public void run() {
        int local_value = MY_INT;
        while ( local_value < 5){
            if( local_value!= MY_INT){
                LOGGER.log(Level.INFO,"Got Change for MY_INT : {0}", MY_INT);
                 local_value= MY_INT;
            }
        }
    }
}

static class ChangeMaker extends Thread{
    @Override
    public void run() {

        int local_value = MY_INT;
        while (MY_INT <5){
            LOGGER.log(Level.INFO, "Incrementing MY_INT to {0}", local_value+1);
            MY_INT = ++local_value;
            try {
                Thread.sleep(500);
            } catch (InterruptedException e) { e.printStackTrace(); }
        }
    }
}

}

问题全都与Java中的volatile关键字用例有关？

如果我在上面的代码中注释了某些部分，volatile关键字将不起作用 注释此代码。

然后易失性关键字不起作用。因为没有Thread.sleep（）？ 谁能对此代码给出解释？