Since you mentioned Hibernate, it's been years since I had to deal with it, but the "generate bytecode for all the things" start-up time of Hibernate/JPA drove

Since you mentioned Hibernate, it's been years since I had to deal with it, but the "generate bytecode for all the things" start-up time of Hibernate/JPA drove me nuts and I built Joist [1] specifically to fix/avoid it. All of Joist's Rails-ish code generation (creating the boilerplate lazy-loaded getters/setters/collections/etc.) is done at build-time so your test-/server boot time is very quick. [1]: http://www.joist.ws/ http://www.joist.ws/