How about a better website for your college?
Or a software to help with something they do regularly, say monitoring the fee payment or registration?
Or how about developing some app for some platform, say android.? That way you get a aroject and could also end up with some cash in your hands and a massively enhanced resume
I am not sure what you meant. Anyways I dont think I am qualified enough to answer that one either.
The framework for email and nearly everything else that works over the internet is standard. So any system that'd involve sending emails would essentially be just piggybacking on it.
Or if you are thinking of creating a software at the user-end (think of the dropbox app on android) then I think pretty much any standard programming language will let you do that, including java.
However, wait for other, more knowledgeable people to comment on this.
I normally follow one rule religiously - never reinvent the wheel. You have existing systems that can be installed to provide facilities on the intranet like file storage, anywhere login, email with attachments, etc. For example, Zentyal - The Linux Small Business Server is a pretty neat distribution that can be installed on a server. It does everything you want to and a lot more and has a beautiful web interface.
Why don't you try making something which doesn't already exist ? It doesn't have to be hard. You can make nifty apps that automate small tasks which become very useful to system admins and/or power users. If you want to go ahead with Java, use Swing to write a GUI for some task(s) or try making a game/animation in it.