title: How to install android app in system/app directory without rooted device so that user can not uninstall that app
body: <p>I made an app which I want to install in system/app directory so that user can not uninstall it. but I want to do it without rooting device. as soon as user download app it will be install in system/app directory. <br><br>I want to do this by writing code.
  I am aiming that users are not allow to uninstall it.</p>