What language are Android apps built in?

Question

I have just started learning about Android and I was planning on making a few apps.

So I was wondering what language do I build apps on and what are the free tools and ebooks about it and also any good IDE for it?

Answer 1

It's in Java and the IDE that can be used is Eclipse: all information on this SDK page

But you should ask this on the Stackexchange site: here