[pjmlp]

A little known secret is that most mainstream languages have nice libraries to handle multi-core programming that go beyond basic thread handling, similar to what Go offers.

You just have to know where to look for, plus you don't need to throw away mature languages and tooling.

[erichocean]

For the JVM, Akka is pretty sweet. It comes with both Java and Scala bindings.

http://akka.io