Comment by pjmlp

I see no reason other than Android, where Android engineers live in the past and don't bother to support modern Java, other than when Kotlin starts to lose the amount of Java libraries able to run on Android.

Many years ago I learnt that mastering the language that goes alongside the platform is quite valuable versus the languages that come and go.

Hence why despite my rants, I keep my C knowledge up to date, as it is the language of UNIX, same with JavaScript on the Web, Erlang on BEAM, and naturally Java on the JVM, even though Scala and Clojure are much cooler.