Download from http://www.eclipse.org/.
Install the application.
Run the application.
Select the workspace you would like to work in.
File -> New… -> Project…
Java Project
Next
Enter a project name.
Next
Finish
Right Click on the Project folder
New… -> Class
Enter the name of the class (java class)
Check the ‘public static void main(String [] arg)’ option if this is the main class.
Code away.