Got it! Thanks moogie.
I was interested to see that your help file says that Pack200 was not allowed by the competition rules, but the rules on java4k.com say that it is allowed. I guess the rules changed one year?
Also, I'm trying to build the jar for one of the 2013 entries from source. I can build the class and jar file fine (using Eclipse), and a quick run through with 4KJO brought it down to 4.5 kb. I'm going to keep experimenting, but are there any obvious points I might have missed which account for the extra 500 bytes or so?