I just noticed that the jruby.jar created by the default ant tasks already has the OSGi metadata. Unfortunately, the jruby-complete jar (needed by warble and the JRuby on Rails .war files) does not.
According to the bug, the metadata was needed for Glassfish v3.
[I just packed off a patch to JRuby's build.xml to jruby-user to OSGify jruby-complete "the same way" as jruby.jar. (Is that too many senses of "to" in less than two sentences?)]
"The Global Cyber Game"
3 hours ago