At the moment JOGL only exposes an immediate mode version of glDrawElementesInstancedEXT:
GL.glDrawElementsInstancedEXT(int, int, int, Buffer, int)
According to the OpenGL spec, this method only works with VBOs. Hence this method should accept a long instead of a Buffer. Unfortunately, JOGL does not provide a VBO version of this method.
Also, these two methods are missing entirely:
CgGL.cgSetCompilerIncludeCallback()
CgGL.cgSetCompilerIncludeString()
This makes it really difficult to combine shaders. Are there any plans to add these features to JOGL?