Theoretical alternative, while I'm deeply excited about .NET Core on Linux (mostly for when F# is fleshed out) it's not got the massive ecosystem Java has yet and might not have for a while since Java on Linux (and others) has been around quite a while.
If Microsoft would create a bridge that allowed use of Java libraries from .NET I think a lot of projects would consider moving to .NET. A while a go I did some text processing projects and the existence of frameworks like Lucene and Tika alone were a big argument for Java.