A DESCRIPTION OF THE PROBLEM :
The text :

Throws:
    NullPointerException - if first or last are null
    IllegalArgumentException - if first.compareTo(last) > 0


... should be :

Throws:
    NullPointerException - if from or to are null
    IllegalArgumentException - if from.compareTo(to) > 0


URL OF FAULTY DOCUMENTATION :
http://java.sun.com/javase/6/docs/api/java/util/EnumSet.html#range(E,%20E)