Several people have mentioned Play. There's also Grails, designed as an familiar clone of Rails. There's also Spring Roo, and JBoss's SEAM. Scala also has Lift and Clojure has Compojure (if Lisp style languages are your thing) So plenty of choice!

I'd highly recommend using Matt Raible's JVM web framework evaluation technique and then following up with a prototype in the top two. Time spent up front deciding on the framework that fits you will be time well spent.