bodyMassIndex isn't declared properly. It needs a datatype and a semi-colon.
Also, you are mixing swing and cli here. Once you've been prompted for input in the gui, you'll then need to proceed and enter on the command line. Choose to either use an entire gui application and stick with the swing components, or drop the swing and run it on the command line. Don't mix the two.
Also, in the future please wrap your code in [php][/php] or [code][/code] tags to preserve the formatting.
header('HTTP/1.1 420 Enhance Your Calm');