Which domain should i do my final semester project whether Android, Java or DOT NET?

You have already answered your question in the question itself. Go with your interests. PS - personally I am a big fan of android. Might be I am biased towards it.

If you know the basics of Java and are interested in Android, go for it. Mobile app development skills are in high demand these days and you would also be doing something different from others.

OK first of all dont get offended but you need to get your basics right. Java/.Net/Android are not domains, they are platforms/technologies. http://en.wikipedia.org/wiki/Domain_(software_engineering). Now as far as your project is concerned, I believe you dont have any other option than Android. Reasons : Java apps (jar apps in nokia, etc.) are obsolete or near-obsolate. To develop for Windows phone (I am assuming this based on .Net in your question) you will have to start from scratch to learn C# (essential if not compulsory). Also for windows phone development you'll need windows 8 64 bit machine. ( If i were you I would stick to platform/OS independent technology). You already know Java basics which will speed up your Android learning IMHO. As long as easy is concerned, 'Easy' is relative, what's easy for me might be too tough for you. Dont start working with easy things, your final sem project is something which will help you a lot in finding your real job, believe me a strong project in fresher's CV is way important than his grades. If you want to be a good programmer stay with easy, If you want to be a great one it's start challenging yourself right away. PS: I may sound a bit arrogant because there was none to tell me these things and I realized it the hard way.

Basically dotnet and android have no relationship.. If its a mob app go for android.. If its desktop stick with java. If its web then go for django or rails.. I would advise you to stick with opensource ptograms, got lots of glezibility and potential for expansion.