Java APIs

I made a simple application to calculate the area,permeter and diagonal of a rectangle using user given inputs( length and breadth).

but netbeans is showing error in my source code.When i try to run//compile it it says main class does not exist.
But all the classes exist.Netbeans is not detecting it or something.What to do:

To view the source code,please follow the link.
http://sites.google.com/site/rrahul19932/home/java-error

Edited by: Rahul_Ravi on Jan 30, 2010 9:50 PM