Should I start learning Scala or c++ or AngularJS or R as secondary skill?I have 4 years of experience in Java.?

[Zakaria]

Hi everyone, I have a little problem of ethics. I would like to know should i start learning scala or c++ or angularjs or r as secondary skill? i have 4 years of experience in java. Please help me, Thank you very much for helping me as soon as possible.