Creating a program using Eclipse and Android Add-Ons

Hello!
I am new in computer programming. My professor suggested to use Java as our first step. We need to study about Java and how to create android programs or apps. Can you provide me step by step on how to download this language? How to install it? Is it for free? What are the system requirements to run this functionally? Does require database to make it work? Do I need to install third party software or any other programs to make it work? Please help me I need to start coding immediately.
