Just to follow-up on the inclusion of closures in JDK 7. Mark Reinhold has posted a Q&A in response to the reaction to his announcement at Devoxx '09. He's also now heading Project Lambda which is looking to bring together a closure proposal and prototype as a basis to create a JSR for JDK 7.
There's already a starting proposal on the site and a mailing list has been set up if you want to follow or participate in the discussions.