title: How to grant system permissions to my android app?
body: <p>I'm implementing a demo on silently uninstall an app from device.</p>
  
  <p>In adb shell, I can use pm uninstall packagename to do the task, but when I wrote code, I got some permission denied error.</p>
  
  <p>I've been googling for a while, and found that to get DELETE_PACKAGES permission, I have to sign my app with the same certificate as the system does.</p>
  
  <p>So, can anyone give me some tips on how to do this? Or, is there anyway I can do to make my app running as system service?</p>