So I’m working on a Java 2D overview type of game which Im planning to port over to Android later 
I have worked in pure Java now, but I’ve heard that using Libgdx might be the best choice because of the Androids performance and memory limitations 
My question is if I should too this and do I have to rewrite alot of my code? 
I have already made the player, enemies, animations, powerups, GUI and some more
Everyone will say yes, so yes.
Java2D doesn’t support Android. Even if you were only targeting desktop, LibGDX is still a better choice…
So should I just start a new project and start allover? Seems to me that that would be the best option instead of using alot time on probably rewrite the whole thing…even though I really don’t want too 
LibGDX is pretty much the go-to framework for game development with Java these days. It’s not too low-level in that you won’t need to create your own engines for your game since it does all that heavy lifting for you, but at the same time it’s not too high-level in that you still have ample amount of power and flexibility in terms of being able to create the mechanics you want your game to have and implementing it in the way that you want.
If you want something lower-level that LibGDX to work with - maybe if you want a deeper control and understanding of the inner-workings of your game, you might also want to take a look at LWJGL, which as it turns out, is what LibGDX is largely built on afaik.
You’ll probably have to start all over, but I’d imagine some of the game-specific logic you already have coded will translate to the LibGDX or LWJGL version of what you’re making.
Yeah, Im going to start all over, but still keep the old code to see if I can reuse some of it I also have all my graphics done too so Now Im out looking for some good libgdx tutorials Do you guys happend to know any?
Learn from code is faster. Fetch some test classes from its repository. You can find it in “test” directory.