I have a android project (named : My Application) that uses a dependency (named Utility). I added this java library as a dependency in [My Application]'s build.gradle file :

but in Utility project, I used all java sources (not android manifest and not xml resource files), but I also used import android.os.AsyncTask; import in one of my java files inside that library.
My problem is that, what dependency should I add to Utility's build.gradle file, so it can recognize android.os package. this is my Utility project's build.gradle file : 