Groovy’s creator endorses Scala. Scala is very promising. When I first read Odersky’s academic paper several years ago, I was put off by the complexity of the type system. But it becomes more attractive when you look at the everyday programming aspects of the language. It does a very nice job of synthesizing functional and OO programming, and eliminating a lot of the boilerplate in Java. I would consider Scala for my own work, except that it depends on Java for UI, which is an epic failure. But for server-side programming Scala is a promising alternative to Java.