A lot of Java developers tries to learn Scala or Kotlin.
One problem in this is that some of them really fast hit a barier of uncanny valley ;-)
Both those languages are compiled to bytecode and run on JVM, and are able to use Java types...
When you start from Java, you know how to do stuff.
You starting to write in one of JVM languages, everything goes smooth... and suddenly you find out that in given language they decided to do it in different way.
What is even worse they decided to do it in some strange way (for you as Java developer).
Each time you find such situation you are more, and more frustrated and you start to hate those changes, and by extension whole language.
So, to avoid it, from Java start to use Python or Go. Those are so different that it is almost like learning programming for the first time.
Soon you will gain speed by making in your head some good abstractions.
Learning completely different language is like building bridge over uncanny valley ;-)
Coursera courses - worth of doing?
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My road to automation ;-)
4 steps of evolution of programmer ;-)