Which of the JVM-oriented languages ​​to choose for the Server Side?

Question

Java

Good evening!
For the love of all that's holy, don't breed holivar .
I decided that my knowledge stack was missing the Java language family.
Hence the question: what language (running on the JVM) should I choose for the Server Side now?
Should I start with Java 8, or should I choose Scala / Kotlin / Clojure right away?
An important criterion is the life span of this language.

Answer 1

Scala / Kotlin / Clojure

All this is of course interesting and entertaining, but who will support the project later?
not a single sane PM / lead / customer will choose this exotic for an enterprise
from frameworks, of course, only Spring or pure EJBs

Answer 2

Of these - all will live, but ....
Write that you need a lifetime - so mark in the enterprise.
Duck take Spring and do not rack your brains.

Answer 3

As for me, the most popular stack is Spring/Hibernate/JPA (There is a lot of information available), there is much less about EJB.