I saw that AppFuse was a top project on java.net. It turns out so is WebWork! It got ranked as #4 in most mail traffic on java.net. Except, something is a bit weird with these stats. The #1 project, xlsql, has only had 4 messages to its mailing list.
WebWork had 527 messages in September and 473 in October. So I’ll just assume that WebWork is even higher ranked than it shows here