Application should always running on Top

[pravinvrm]

HI ALL,

I want to use android for a single application only.

Means this application will always running and visible for user interaction, it should not close or go in background and also should not allow user to access other application without permission from this application.

I want to know is it possible? If yes how?

Or it's like an android OS

Any help would be really appreciate.

Thanks
Pravin