I was reading android source code in that I am not getting what does
OPEN GL ES library do and what does
EGL library do.?
Is there any relationship between this two libraries?
I have looked at http://www.khronos.org/opengles/documentation/opengles1_0/html/ but still not getting.
EGL is the interface between OpenGL ES and the underlying native display platform. It is used to create & manage rendering surfaces & graphics contexts.
EGL is used to manage the various display buffers (ie: images you see on the screen) and the OpenGL ES context. These are necessary to use OpenGL ES. So you can think of EGL as an initialization layer for OpenGL ES.
Note that desktop OpenGL has no interaction with EGL, only OpenglES and OpenVG.
Take a look here: Can anyone explain the way the "Khronos stack" of technologies fits together?
Open GL is basically an API for creating applications that draw 2D and 3D graphics. EGL allows you to render APIs like OpenGL. You have many pages explaining this, not difficult to find if you google OpenGL and EGL. For example at khronos.