Scala vs Java if you're NOT going to use Spark?
This is a bit off topic for this SE, or maybe opinion-based, but, I work in this field and I'd recommend Scala.

No I would not characterize Scala as a "stats-oriented" Java. I'd describe it as what you get if you asked 3 people to design "Java 11" and then used all of their ideas at once.

Java 8 remains great, but Scala fully embraces just about all the good ideas from languages that you'd want, like type safety and closures and functional paradigms, and a more elaborate types/generics system, down to more syntactic sugar conveniences like case classes and lazy vals. Plus you get to run everything in the same JVM and interoperate with any Java libraries. 

The price is complexity: understanding all of Scala is a lot more difficult than all of Java. And some bits of Scala maybe were a bridge too far. And, the tooling ecosystem isn't great IMHO in comparison to the standard Java tools. But there again you can for example use Maven instead of SBT. But you can mostly avoid the parts of Scala that are complex if you don't need them. Designing Scala libraries takes a lot of skill and know-how; just developing run-of-the-mill code in Scala does not.

From a productivity perspective, once you're used to Scala, you'll be more productive. If you're an experienced Java dev, I actually think you'll appreciate Scala. I have not liked any other JVM language, which tend to be sort of one-issue languages that change lots of stuff for marginal gains.

Certainly, for analytics, the existence of Spark argues for Scala. You'll use it eventually.