if (systemState != null && lastTimeStamp == systemState.getTimeStamp())
if (systemState != null && timeStamp == systemState.getTimeStamp())
	public void run() {		while (true) {			try {				Thread.sleep(expireTime);			} catch (InterruptedException e) {				return;			}			if (systemState != null && lastTimeStamp == systemState.getTimeStamp())				systemState.unloadLazyData(expireTime);		}	}