android/guava/src/com/google/common/collect/AbstractMapBasedMultimap.java
@Override
  public Collection<V> replaceValues(@NullableDecl K key, Iterable<? extends V> values) {
    Iterator<? extends V> iterator = values.iterator();
    if (!iterator.hasNext()) {
      return removeAll(key);
    }

    // TODO(lowasser): investigate atomic failure?
    Collection<V> collection = getOrCreateCollection(key);
    Collection<V> oldValues = createCollection();
    oldValues.addAll(collection);

    totalSize -= collection.size();
    collection.clear();

    while (iterator.hasNext()) {
      if (collection.add(iterator.next())) {
        totalSize++;
      }
    }

    return unmodifiableCollectionSubclass(oldValues);
  }
@Override
  public Collection<V> replaceValues(@NullableDecl K key, Iterable<? extends V> values) {
    Iterator<? extends V> iterator = values.iterator();
    if (!iterator.hasNext()) {
      return removeAll(key);
    }

    // TODO(lowasser): investigate atomic failure?
    Collection<V> collection = getOrCreateCollection(key);
    Collection<V> oldValues = createCollection();
    oldValues.addAll(collection);

    totalSize -= collection.size();
    collection.clear();

    while (iterator.hasNext()) {
      if (collection.add(iterator.next())) {
        totalSize++;
      }
    }

    return unmodifiableCollectionSubclass(oldValues);
  }
{@inheritDoc}

<p>The returned collection is immutable.