This is such a weird thread. I'll comment and say that you can't expect to develop in one language for your entire career. You'll just end up stagnate and unemployable or only employed for "legacy maintenance"
Oh OK, Java is added to the list as an example of extreme Object Oriented programming.
But that is not the reason it was not important to enough to occur to me. Java is actually not important.
Since exploring it when it was a new thing I have never figured out what it was for. I already had classes/objects in C++ why would I want a slow and bloated version of that idea that also precludes free functions whilst not even being usable in many places I need to program?
This isn't a great idea. Different languages are good at different things and restricting yourself to a single language is just going to hurt you in the long term.
Choose the right tool for the job. Don't constrain yourself to a single way of doing things.