When I was reading about development, it said that app development is done with the help of Java and other APIs. But since Python is much more easier than Java, isn't it possible to make an app with Python?
Certainly Possible. You need to use other cross-platform Frameworks like Kivy (kivy.org) to achieve this. Just search Python android and You'll get many options.
But, If you want to use ADT, then You'll have to code in java.