I'm not that familiar with Scala, but I have done some significant Clojure work, and I can assure you, the difference between inner classes and closures is significant. Having used C# for many years, it's notable that people started to use closures vastly more after Microsoft improved the syntax.

And yes, Hibernate really is that gnarly. Imlementing a rest/Jason interface in Clojure is vastly easier, never mind simpler.