1 Answers
File- It is a block of arbitrary information, or resource for storing information. It can be
of any type.
Class- Its a compiled form of .Java file . Android finally used this .class files to produce an
executable apk
Activity- An activity is the equivalent of a Frame/Window in GUI toolkits. It is not a file
or a file type it is just a class that can be extended in Android for loading UI elements on
view.