The GorupsModelArray will throw an error when passing it a list with a generic type, this happens when it tries to call an overriden method to createGroupFoot with the generic type. Please see the attached code for more information.

This should be an easy fix, in the constructor instead of using:

(D[])data.toArray()

use

(D[])data.toArray(new Food[0]) where Food is the generic type

The attached code contains a static void main method so it can be run independently for ease of testing.