A friend of mine found this tidbit in the Java API (https://docs.oracle.com/javase/7/docs/api/java/lang/Enum.html),
Class Enum<E extends Enum<E>>
and by reading the following article https://docs.oracle.com/javase/tutorial/java/generics/genTypes.html I could understand what the aforementioned line entailed syntactically but from the examples given I could not figure out a use case for this beyond the Enum class (reviewed the source).
I'd like to learn more about possible problems where the above may present a solution.