By robust, I mean the language/compiler has a strong test suite and the runtime is known to work reliably in production settings. I've heard horror stories about Sun's HotSpot JIT crashing frequently, but that was what, 10 or 20 years ago? Now that I think about it, Scala might be a modern example of that, but I haven't kept up with how they might have improved.
In this case, yes, real-world languages have a solid runtime/compiler. Though I'm surprised you have issues with Scala, at least the runtime part should be rock solid, given that it runs on a very much battle-tested JVM.