If you run
jar -xf soccer.jar,
change to the META-INF directory, and look at the MANIFEST.MF file, what does your Main-Class attribute look like?
Also, how are you invoking the jar file? (Remember, you have to include the -jar switch, so your command line should look like:
java -jar soccer.jar)
Piscis Babelis est parvus, flavus, et hiridicus, et est probabiliter insolitissima raritas in toto mundo.