title: Need to implement full fledged Multiple User Account in JB Android
body: <p>I want to build a full fledged Multiple User Account in JB Android. I know it can be done using Lollipop but I want it on existing system of JB. </p>
  
  <p>1) What all level of changes do I need to make?
  2) UserManager class is present in JB , I think I need to make changes in it? apart from framework , Where all I need to make changes?</p>