Contact retrive from server in android app and match and store in sqliite db locally

I am making an android app.The scenario is like this: I have contacts stored in the server which is retrieved using retrofit library,in json format which I display directly in the listview.I want to store these contact locally and also sync with the server if any information regarding contact changes either in phone or on server.There are some 1000 contact per user so retrieving every time from server is not possible. What method should i follow to implement all the above?