guava/src/com/google/common/collect/Serialization.java
static <E> void populateMultiset(Multiset<E> multiset, ObjectInputStream stream)
      throws IOException, ClassNotFoundException {
    int distinctElements = stream.readInt();
    populateMultiset(multiset, stream, distinctElements);
  }
static <E> void populateMultiset(Multiset<E> multiset, ObjectInputStream stream)
      throws IOException, ClassNotFoundException {
    int distinctElements = stream.readInt();
    populateMultiset(multiset, stream, distinctElements);
  }
Populates a multiset by reading an input stream, as part of deserialization. See {@link
#writeMultiset} for the data format.