Installing Java & Setting up for your first program
If you want to write & run Java programs you need to install JDK in your system and you need an editor. Eclipse & IntelliJ Idea are the two most commonly used editors. I recommend eclipse for beginners and if your primary goal is to develop Android Applications then I recommend IntelliJ Idea as the Android Studio is built on the IntelliJ platform.
Following video shows you how to setup Java & Eclipse on your computer.