Im new here and want to ask a question. I want to make games so I decided to start with java 2d game. I know java basics and have almost no experience with it. I found some nice engines like slick2d but they were outdated. From new ones I found libgdx and jrabbit. They both have a similar functionality described on their “features” pages.
I want to know whats better for a newbie to start with. I mean 2d java engine 
Slick2D is your best option as a newbie and for a 2D game. I have personally never used JRabbit but I can recommend LibGDX as an excellent library for when you learn a bit more about OpenGL.
slick2d is outdated?! :o
It works but it is effectively dead. Kevglass does bug runs every so often but he will not be adding any more features.
libgdx isn’t for noobs?!
Thanks for replies. I browsed forum a bit and decided to start with tutorials first :). And 1 more question. How much time do I need to spend on prototyping my game on the paper before using java itself?
You need to spend exactly the amount of time that you need before being comfortable with coding it.
Wow. I had no idea x = x.
I doubt there is a more correct answer, it will take different for everyone
Mike
In my term, you need time until you know how to code it