I have to make a java game with openGl to my school. At first I thought that I will make simple 2D game with help of LWJGl. But how can OpenGl help with simple 2D?

I have to make a java game with openGl to my school. At first I thought that I will make simple 2D game with help of LWJGl. But how can OpenGl help with simple 2D?

Impossible to answer this without writing a book for you. If you're in a computer graphics course at your school then you should study the reading material.

There are tons of reading material online as well, demos, examples, tutorials etc. Just google the keywords.

OpenGL can be used for 2D applications. Look up resources with google like "Lighthouse" or "Nehe" OpenGL Tutorial.

For 2D you want to pay special attention to glOrtho (that makes a "window" for 2D drawing). Then you can draw using only the 2 familiar coordinate system (cartesian coordinates).