Android应用被killed时，Service不被一起kill的方法

@Override
public int onStartCommand(Intent intent, int flags, int startId) {
Log.d(TAG, "service on start");
Log.d(MyService.TAG, "MyService main thread:" + Thread.currentThread().hashCode());

Notification notification=new Notification();
notification.tickerText="HAHA";
this.startForeground(startId, notification);

try {

Thread.sleep(10000);
} catch (InterruptedException e) {
e.printStackTrace();
}
return super.onStartCommand(intent, flags, startId);
}