Last week, we had the author of TDD for a Shopping Website LiveProject. Friday at 11am Ranch time, Steven Solomon will be hosting a live TDD session just for us. See for the agenda and registration link
Android is an operating system; are you asking how to send notifications to particular devices that run Android? If so, what distinguishes those devices, or in other words, how do you decide which devices to send the notification to?
Also, what do you mean by "using Java"? Would this be a server app or desktop app written in Java?