休眠的线程如何接收事件?

我的代码:

public class EventHandler implements Runnable, SomeEventListener {
    private static final EventHandler INSTANCE = new EventHandler();
    private static final Thread THREAD = new Thread(INSTANCE);
    private static volatile boolean isRunning = false;

    private EventHandler () {}

    private static EventHandler getInstance() {
        return INSTANCE;
    }

    public void start() {
        isRunning = true;
        THREAD.start();
    }

    public void stop() {
        isRunning = false;
    }

    //Listener method that was overriden
    public void onEvent(Event event) {
        //...do stuff
    }


    @Override
    public void run() {
        //Do nothing, let the listener do its job
        while (isRunning) {
            try {
                logger.info("Sleeping...");
                Thread.sleep(5000);
                logger.info("Done sleeping...");
            } catch (InterruptedException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
    } 
}

} 基本上 run() 这个方法什么也不做——每5秒就睡一次,醒来后再睡一次。我不明白的是,当它睡着的时候 EventHandler 类仍然会获取事件。这是怎么发生的?由于线程处于休眠状态,类不应该停止接收事件吗?