guava-gwt/src-super/com/google/common/collect/super/com/google/common/collect/ForwardingSortedMultiset.java
protected SortedMultiset<E> standardSubMultiset(
      E lowerBound, BoundType lowerBoundType, E upperBound, BoundType upperBoundType) {
    return tailMultiset(lowerBound, lowerBoundType).headMultiset(upperBound, upperBoundType);
  }
protected SortedMultiset<E> standardSubMultiset(
      E lowerBound, BoundType lowerBoundType, E upperBound, BoundType upperBoundType) {
    return tailMultiset(lowerBound, lowerBoundType).headMultiset(upperBound, upperBoundType);
  }
A sensible definition of {@link #subMultiset(Object, BoundType, Object, BoundType)} in terms of
{@link #headMultiset(Object, BoundType) headMultiset} and {@link #tailMultiset(Object,
BoundType) tailMultiset}.

<p>If you override either of these methods, you may wish to override {@link
#subMultiset(Object, BoundType, Object, BoundType)} to forward to this implementation.