Both of my last 2 large bank gigs (kind of the last places you'd expect cutting edge tech) were going all in on Kotlin. New projects were Kotlin only, and there was active work on sunsetting/migrating Java applications towards Kotlin. None of these were Android applications.

Sure, this is anecdotal. But I'd say the same of Java's dominance in the JVM space. Java's continued dominance is not a sure thing from my vantage point.

JVM is written in a mix of Java and C++, let me know when they start rewriting it in Kotlin.

Groovy was all the adoption rage across German JUGs back in 2010, then everyone was going to rewrite the JVM in Scala, or was it Clojure?

Now a couple of places are adopting Kotlin outside Android, nice, eventually will migrate back in about 5 years time.

https://trends.google.com/trends/explore?q=%2Fm%2F07sbkfb,%2...

> JVM is written in a mix of Java and C++, let me know when they start rewriting it in Kotlin.

This is less relevant today. The host blessed languages do have an advantage, but I would not say it is insurmountable. It might have been the case in the past, but the modern JVM is a platform, it is no longer a glorified Java language interpreter.

> Now a couple of places are adopting Kotlin outside Android, nice, eventually will migrate back in about 5 years time.

Maybe. Maybe not. Most developers I talked to that have experienced the transition do not want to go back to Java.

This isn't to say Java will die. It will continue to thrive. But Java dominance (on the JVM or as a whole) isn't a sure thing anymore.