Is it possible to use Ruby/jRuby/Java on Google App Engine?

I understand it possible to do jRuby/Java on Google App Engine, but is I also want to use Ruby on Rails as the fron开发者_如何学编程t end in that setup, will I be able to?

Thanks, Alex

http://code.google.com/p/appengine-jruby/

It supports Rails with the current versions: 2.3.5, 2.3.8, 2.3.9, 2.3.10 and 2.3.11, with support for Rails 3 soon. It also supports Sinatra.