I didn't know this was possible until recently I force quitted an app and when I restarted my phone I found it had a service running in background and the force quit button became unclickable. There are a lot permissions in that app one of them is modify system setting, does it have anything to do with this permission? what methods use this permission? how can I do the same with me app?
possible duplicate of Trying to start a service on boot on Android