I can tell you from my personal experience that Java is good to understand the OOP concepts but it comes with a big issue. It is slow, it is restricted to devices that can get JVM installed into them. Hence I don't think it will be around for very long. The only reason it is still breathing is because many large projects were written in Java and now it would be big trouble to conver them to Python or JS.
On the other hand, JS is burning hot right now. It can do almost anything with Google's V8 engine. Then there is python which is then new language for Scientific stuff.
C is also a great language if you know how to control it.