hi everyone, I know there are other game libraries that use fast Math classes, I use common Math class, so my question is:
is ok if we use Math class, or do I need to look for a FastMath library to use it in my projects?
It’s ok as long as you meet your performance goals on the slowest system you want to support, your players won’t decompile your game and look at which math classes you use and judge you based on that.
BUT it’s always good to have some performance buffer and most custom java math libraries are just as simple to use as the standard math lib, they might even have some additional features (gamedev specific functions) that make your life much easier, so i would suggest you just use whatever custom math lib catches your eye.
LibGDXs math library for example is just as easy to use and has some additional features, so that’s one candidate, but there are even better ones, it’s all up to you.
The current state of the art in maths libraries is JOML - highly recommended. Doubt you need it for a JavaFX application though!
Cas 
I was looking yesterday and found two options:
1.- JAFAMA
2.- apache FastMath
I will do little research and will check LIBGDX math as well, however libgdx math should be better option due is for a game library/emgine