Which library (LWJGL/JOGL) shall I learn before I move on to using C++ with OpenGL/SDL? I want to know which of these two are probably the best and most similar to OpenGL in C++ so I can eventually move on to that with OpenGL, after of course have a skills in C++.
Currently I have some basic knowledge in C++, but at the moment I'm most comfortable and experienced with Java.
Thank you kindly.
Stick with whatever language works for you. If you're making your AAA 3D game and you notice that Java is too slow, than jump to C++. But you probably won't be making AAA games anyway. If you're comfortable with Java, just stick with it.
If you like to play with other people's features, you should try libGDX. I love to be able to draw stuff onto the screen with OpenGL without any other abstractions, so I use LWJGL. It's almost the same as C++. LibGDX is a not an API, it is more like game framework.
If you still plan to jump into C++ for some reason, and you want your skills to be as compatible with other languages as possible, you should probably choose LWJGL.
I haven't tried using JOGL, but I wanted to test is at some time. My journey ended once I realized you need to do a lot of stuff manually. Anyway, stop planning. Start doing. If you learn using LWJGL, your skills won't go to waste.