Ask HN: If you know Clojure and Scala, is Java still worth learning?

if you want to apply for Java job at the the company which needs core Java, yes, you can easy learn some Java, and play with some core stuff, though you can do it in Scala too. But most companies outside SV need Enterprise Java experience and that can be a problem as it needs much more time investments, ideally at work, and after Clojure you can find this stuff boring as hell, clunky and awkward. I have similar issue now - I have experience in Scala, Play framework, Akka, no JEE. I decided to get some Rails and Javascript experience outside work to have more chances on job market.

If you REALLY want to know Scala/Clojure, learn lower level Java and the JVM itself. IMO, you can only go so far without that knowledge.

Java, as a language, is pretty easy to learn. If you already know the standard library from Scala/Clojure, even more so.

That said, some parts of the ecosystem that are built around (Enterprise) Java are real behemoths and the companies may actually be looking for experience with a particular framework/library than just generic Java experience.

I think it's not going to hurt. I gathered up the reasons in a small write up here (Why Java is Still Relevant): https://medium.com/i-m-h-o/da3b2c180e9c

For a small number of tasks in Clojure, it's very sensible to write a Java program that handles what you want to do, then call it from Clojure. Here's an example: http://stackoverflow.com/questions/14949705/clojure-performa...

I really don't think it's worth learning no matter what language you know.

As soon as you touch a library written in java (read as "designed for"), you start to think in terms of java features and how they map to your language of choice. The oft touted benefit of utilising java libraries suddenly becomes a chore since you are now juggling two different languages in your head.

Learn java if you touch JVM, there is no escape.