code: public static <E extends Comparable<?>> Builder<E> reverseOrder() {
      return new Builder<E>(Ordering.natural().reverse());
    }
docs: Returns a builder that creates immutable sorted multisets whose elements are ordered by the
  reverse of their natural ordering.
  
  <p>Note: the type parameter {@code E} extends {@code Comparable<?>} rather than {@code
  Comparable<? super E>} as a workaround for javac <a
  href="http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6468354">bug 6468354</a>.