Hey guys…
I have a stupid little question about LWJGL and LibGDX.
I heard that LWJGL is “lower level” than LibGDX.
And I know… the question is maybe stupid… But what is the meaning of “low level” in this case?
You know. I try to figure out which one is better to start with for newbies. In my opinion it is LibGDX. As I read some posts here I saw that you talk about “low level” and so on. I have a assumption… but… in fact i don’T know it 
Thanks alot
Well it’s pretty easy:
LWJGL is just a wrapper to OpenGL , OpenCL and OpenAL for Java.
LibGDX uses LWJGL underneath and do some of the boilerplate code for you.
If you going to start and want to learn pure OpenGL/OpenCL/OpenAL use LWJGL, if you want to make games faster then use LibGDX 
low level:
render(byte[] pixels, int width, int height, int format);
high level
render(Sprite sprite);
High level is an abstraction of sorts, its generally easier to use because a lot of the harder stuff is done for you.
Low level is “harder” to work with because you need to connect the dots basically. For instance, LWJGL is only a graphics API. It doesn’t support text rendering, texture loading etc… You have to do it yourself (connect the dots)!
Ahhh thank you guys!
Now I get it!! :))