It unifies the type system, which gets one of the big headaches of Java out of the way.

It has a generics system that makes a lot more sense (allowing covariant/contravariant types, rather than forcing use-site variance everywhere).

Case classes are wonderful for making simple data classes easy to read (and write).

Honestly Scala is all about solving the pain points with Java, so just look at anything that's been written about it. http://www.scala-lang.org/

right, all nice to have things.

Does it actually solve any real problems?

Does it fix GC performance? Does it fix API issues? Does it remove the need for JNI bindings to native code?

No?

Repetitive code is a real problem. Or do you think performance is the only thing that can ever qualify as a "real problem"?

Implicits make it much easier to deal with API issues.

1) GC: VM issue. Has nothing to do with language. 2) API: Google's responsible for the Android API's but Scala's standard library is definitely better than Java's. 3) JNI performance is a VM issue, again, and JNI interface is Google's problem.

These problems are not solvable by any language.