Scala, Clojure, Kotlin, Ceylon, Groovy and now Xtend. Going to be interesting to see what languages win out in what niches on the JVM.
i wanted to learn either scala or clojure and decide to pick the language with tighter java libraries integration (the language that makes it easier to use java lib), and according the the reviews i read, clojure won in that area
if the level of activity around clojure continues at this rate, i believe it will easily outshine the competition
also dont discount jRuby, it has a nice following
Using Java code from Scala is literally the same as using Scala code from Scala. Same thing if you replace Java with Scala and Scala with Java (with the exception of some Scala constructs that aren't present in Java).
This is not true of Clojure..
http://codemonkeyism.com/clojure-scala-part-2/
looked trust worthy to me!