"Should not contain null after unsupported putIfAbsent(present, null)");
  }

  @MapFeature.Require({SUPPORTS_PUT, ALLOWS_NULL_VALUES})
  public void testPut_nullValueSupported() {
    Entry<K, V> nullValueEntry = entry(k3(), null);
    assertNull(
        "putIfAbsent(key, null) should return null",
        getMap().putIfAbsent(nullValueEntry.getKey(), nullValueEntry.getValue()));
    expectAdded(nullValueEntry);
  }

  }

  @Override
  Entry<E> getEntry(int index) {
    return Multisets.immutableEntry(elementSet.asList().get(index), getCount(index));
  }

  @Override
  @CheckForNull
  public Entry<E> firstEntry() {
    return isEmpty() ? null : getEntry(0);
  }

  @Override
  @CheckForNull
  public Entry<E> lastEntry() {
    return isEmpty() ? null : getEntry(length - 1);
  }

                buf.setLength(0);
                buf.append('{');
                boolean first2 = true;
                for (final Map.Entry<String, Object> entry : doc.entrySet()) {
                    final String name = entry.getKey();
                    if (StringUtil.isNotBlank(name) && entry.getValue() != null) {
                        if (!first2) {
                            buf.append(',');
                        } else {

  }

  @MapFeature.Require(SUPPORTS_PUT)
  @CollectionSize.Require(absent = ZERO)
  public void testPutDuplicateValue() {
    List<Entry<K, V>> entries = copyToList(multimap().entries());

    for (Entry<K, V> entry : entries) {
      resetContainer();

      K k = entry.getKey();
      V v = entry.getValue();

      List<V> values = multimap().get(k);
      List<V> expectedValues = copyToList(values);

    throw new UnsupportedOperationException();
  }

  /** @since 12.0 */
  @Override
  public void putAll(Map<? extends K, ? extends V> m) {
    for (Entry<? extends K, ? extends V> entry : m.entrySet()) {
      put(entry.getKey(), entry.getValue());
    }
  }

  @Override
  public void cleanUp() {}

  @Override
  public long size() {
    throw new UnsupportedOperationException();
  }

     */
    @CanIgnoreReturnValue
    @Override
    public Builder<K, V> put(Entry<? extends K, ? extends V> entry) {
      super.put(entry);
      return this;
    }

    /**
     * {@inheritDoc}
     *
     * @since 19.0
     */
    @CanIgnoreReturnValue
    @Override
    public Builder<K, V> putAll(Iterable<? extends Entry<? extends K, ? extends V>> entries) {
      super.putAll(entries);

      for (Object object : entries) {
        Entry<Country, Currency> entry = (Entry<Country, Currency>) object;
        result.put(entry.getKey(), entry.getValue());
      }
      return result;
    }

    @Override
    public SampleElements<Entry<Country, Currency>> samples() {
      return new SampleElements<>(
          mapEntry(Country.CANADA, Currency.DOLLAR),

  public static void assertMapEntryIsUnmodifiable(Entry<?, ?> entry) {
    try {
      // fine because the call is going to fail without modifying the entry
      @SuppressWarnings("unchecked")
      Entry<?, @Nullable Object> nullableValueEntry = (Entry<?, @Nullable Object>) entry;
      nullableValueEntry.setValue(null);
      fail("setValue on unmodifiable Map.Entry succeeded");
    } catch (UnsupportedOperationException expected) {

    return (Set<V>) super.replaceValues(key, values);
  }

  @Override
  Set<Entry<K, V>> createEntries() {
    return Sets.filter(unfiltered().entries(), entryPredicate());
  }

  @Override
  public Set<Entry<K, V>> entries() {
    return (Set<Entry<K, V>>) super.entries();
  }

    Iterator<E> iterator = collection.iterator();
    Object element = iterator.next();
    // If it's an Entry, it may become invalid once it's removed from the Map. Copy it.
    if (element instanceof Entry) {
      Entry<?, ?> entry = (Entry<?, ?>) element;
      element = mapEntry(entry.getKey(), entry.getValue());
    }
    assertTrue(collection.contains(element)); // sanity check
    iterator.remove();