Glassfish v3 is modular, so you can easily install and uninstall modules on the fly. Therefore it is very easy to measure the "disc-size" of a particular technology. The whole installation package (for GF v3 prelude b24) takes ...324 KB (three jars: connector, timer service, and the actual implementation). It is small enough to be executed on SunSPOTs or cellular phones.... So how would you call a complete framework with 324 KB "Heavyweight"? :-)
I plan to demonstrate this, as well as some Java EE 6 features at JUG HH. Warning: some design patterns will probably die during the session :-). So see you in Hamburg!