[vorg]

> JVM-based languages (like Clojure, Groovy, Scala, and JRuby) are quickly gaining popularity in enterprise environments that already use Java

They are. Though of the 4 examples you gave, only Scala's really being used to build systems, though Clojure's being used by some who don't mind forgoing static typing. Groovy's a scripting language used for short test and build files, and for Grails. I don't think JRuby ever got used much in production.

[yellowapple]

You might be right about Groovy. I've seen JRuby used pretty heavily in enterprise environments, though (usually to integrate Rails with an existing Java-based system).