> rely heavily on Java libraries If you're referring to the storage engines, those are not Java, and even then, most storage engines of a database will resort

> rely heavily on Java libraries If you're referring to the storage engines, those are not Java, and even then, most storage engines of a database will resort to a lower level language because of the need to care about memory layout and things that are simply not exposed to you in a high-level language like Clojure (or Java, unless you are somehow able to use Jikes RVM in production, I guess, but I'm not aware of ANYONE using a Java storage engine atop Jikes)