> It will never be as good as a modern language like Kotlin (data classes are my favourite feature there), but it is good enough

Data classes may come to Java.

http://cr.openjdk.java.net/~briangoetz/amber/datum.html

http://mail.openjdk.java.net/pipermail/amber-spec-experts/20...

Fibers, continuations, string literals, pattern matching and value types are in the works.

http://cr.openjdk.java.net/~rpressler/loom/Loom-Proposal.htm...

http://openjdk.java.net/jeps/326

https://www.youtube.com/watch?v=n3_8YcYKScw

http://openjdk.java.net/projects/valhalla/