guava/src/com/google/common/collect/Multisets.java
static <T> Multiset<T> cast(Iterable<T> iterable) {
    return (Multiset<T>) iterable;
  }
static <T> Multiset<T> cast(Iterable<T> iterable) {
    return (Multiset<T>) iterable;
  }
Used to avoid http://bugs.sun.com/view_bug.do?bug_id=6558557