Perhaps Gosu is the next Big JVM Language?
http://gosu-lang.org

- Syntax is similar enough to Java
- Far simpler than Scala (Java programmers will have no trouble transitioning)
- Wide range of modern features (properties, closures, composition, type inference, type enhancements, etc.)
- The type system is apparently open (!) they're going to deliver XML types etc. (they have a Dynamic type example that seems too good to be true)
- Advanced IDE support with their Eclipse plugin, and they bundled a script editor that is quite capable
- They claim the language is already being used by multi-billion dollar companies

Seems to have all the ingredients.

>> Groovy has a distinct niche with its ability to fill in Java's need for a scripting language. Groovy will have a role in build scripts, particularly with Gradle. It will perhaps have an important role in web apps as well.

Can not agree that scripting is a primarily application of groovy. Many, including myself and my team, choose groovy over java because of its conciseness and productivity gains. The kind of of apps you can build with groovy is pretty much everything you can build with Java SE/EE.

cala advocates don't like to hear that Scala is too complicated, but it's a fact that this perception is widespread.On the other hand, the CLR has arguably got a few decisions "more correct" than the JVM: