Charles demoed the Depot 2 application (from Agile Web Programming with Rails) application running on JRuby, integrated with a JMX bean and using JDBC as the database library. Needless to say, this is seriously cool. I asked about integration with Java EE on different tiers. Oliver’s answer was that integrating the JRuby runtime via a servlet should be easy (and has in fact been done for JavaOne), but using JRuby for e.g. writing EJBs (or rather, ERBs) would be a lot harder. My guess is that’s going to change once JRuby compiles down to byte code.
Even though it still performs quite a lot worse than Ruby (or CRuby, as he called it) — about 2-3 times worse — the online Depot demo looked perfectly fine. I also inquired about Strongtalk, and he confirmed that he is very interested and willing to work together with the original engineers who are still at Sun to profit from it.