Java is still the top dog on JVM, but there are plenty of alternatives for those programmers who a looking for a change, but how valid are these options? It’s hard to make a case for learning a fringe language apart from personal enjoyment, but do these alternate languages offer valid career paths. To do so, what you need is a critical mass of developers using it to motivate tool makers to create proper tools for those languages. When there are users, then libraries will follow.

I selected tree of the most talked jvm languages apart from Java which are: Scala, Clojure and Kotlin.

Scala is the oldest of these three being released already in 2004. Clojure followed in 2007 and Kotlin being the most recent of these languages being unveiled in 2011 and reaching version 1 early 2016.
 

New Interest

Past 12 Months:

Blue: Scala tutorial, yellow: Kotlin tutorial, Red: Clojure tutorial

Link to most recent graph.

Past 5 years:

Link

Scala seems still the most interesting to newcomers. Kotlin popularity clearly spiked mid 2017, but the hype has slowed down a bit since.

Job Market

How useful are these languages in the job market.

LinkedIn Job Search:

software engineer scala Showing 5,540 results
software engineer clojure => Showing 684 results
software engineer kotlin => Showing 586 results

engineer scala => Showing 7,701 results
engineer clojure => Showing 778 results
engineer kotlin => Showing 433 results

data scala => Showing 10,076 results
data clojure => Showing 758 results
data kotlin => Showing 254 results

Based on LinkedIn Worldwide job search Scala is mentioned in roughly 10 times more job adds than Clojure. Kotlin seems to be catching on quite quickly, apparently being officially supported by Android drives adoption. I would be surprised if it did not take over Clojure in popularity in the next 6 months.

Scala benefits from growing data science/engineering market as it’s one of the most important languages in that domain alongside Python. Quite a few data processing tools(Spark, Kafka) are written in scala making it the most natural fit for

Salaries

How well do these salaries pay:
It’s hard to find reliable data on how jobs in given languages pay. Googling around I found this article:
https://gooroo.io/GoorooTHINK/Article/16300/Programming-languages–salaries-and-demand-May-2015/18672#.WfEECxOCzXE
Looks like clojure pays pretty well and clearly better than scala. Both however pay clearly better than numerous java or javascript jobs. Jobs that require functional language knowledge are still fairly few, but if you manage to land one, you will be pretty well compensated.