Description from Scott:

public class Enum<E extends Enum<E>>
  extends Object
  implements Comparable<E extends Enum<E>>, Serializable

It actually implements Comparable<E> and Serializable.

The bounds of a type parameter should only be displayed in the
declaration of that type parameter. So "Enum<E extends Enum<E>>"
is correct since that's where "E" is declared, but "Comparable<E>"
because that's just a use of the same "E" that's declared in the
first line.