老师，在我没有使用Volatile和Synchronized关键字时，为啥加了睡眠就有可见性，不加就没有可见性呢？
代码如下：

public class ThreadSafeCache {
    int result = 100;

    public int getResult() {
        return result;
    }

    public void setResult(int result) {
        this.result = result;
    }

    public static void main(String[] args) throws InterruptedException {
        ThreadSafeCache threadSafeCache = new ThreadSafeCache();
        Visibility visibility = new Visibility(threadSafeCache);
        for (int i = 0; i < 8; i++) {
            Thread thread = new Thread(visibility);
            thread.start();
        }
        Thread.sleep(1000);
        threadSafeCache.setResult(200);
        int x = 1;
        while (true) {
            x++;
        }
    }
}

class Visibility implements Runnable {
    private ThreadSafeCache threadSafeCache;

    public Visibility(ThreadSafeCache threadSafeCache) {
        this.threadSafeCache = threadSafeCache;
    }

    @Override
    public void run() {

        int x = 0;
        while (threadSafeCache.getResult() == 100) {
            x++;
            /**
             * 加了睡眠就有可见性，不加就没有
             */
            try {
                Thread.sleep(1);
            } catch (InterruptedException e) {
                e.printStackTrace();

            }
        }
        System.out.println(x);

    }
}