Java is OOP taken to the extreme, and you’ll definitely the miss the versatility a language like C++, Python or JS offer regarding that.
Despite my personal dislike for it, it’s still pretty important because a ton of big enterprise software plus Android use it, so it’s definitely worth learning.
I don’t want to repeat the answer again. I 'd suggest to look for answers to similar questions at stackoverflow.com.
Java is the first programming language I learned. As a part of a project I am developing Android app(Java) , server (JS) and admin panel in react(JS) .
All I had to do with react was to use fetch() and learn a little bit about promises which I find extremely useful.
My fav quote from that SO link: