It seems the author doesn't know much about Scala. There seem to be quite a bit of "Fan vs. Scala" posting from Fan fans with this characteristic. No overload

It seems the author doesn't know much about Scala. There seem to be quite a bit of "Fan vs. Scala" posting from Fan fans with this characteristic. No overloading: since Fan doesn't have Hindley-Milner type inference, it seems like a loss to drop overloading. Presumably they did this to make the language implemenation simpler. Wildcard type: "Any" in Scala is an available supertype to everything, including primitives. It sounds like Fan has some unsafe automatic type conversion going on that you'd have to make explicit in Scala. Immutability: in Scala, "val" is immutable, "var" is mutable. This is SUPER basic stuff; I'm not sure how you miss that. As for libraries, build system, JSON: Scala actually has all that (but it looks like Fan has some additional JSON config integration built in) You can pass Scala objects to Java libs (callbacks, observers, etc.) and it just works. There's almost no difference between using Java and Scala, which is a pretty strong point.