private final Map<K, V> backingMap;

  /*
   * Per JDK: "the behavior of a map entry is undefined if the backing map has been modified after
   * the entry was returned by the iterator, except through the setValue operation on the map entry"
   * As such, this field must be cleared before every map mutation.
   *
   * Note about volatile: volatile doesn't make it safe to read from a mutable graph in one thread

      @SuppressWarnings("unchecked")
      Entry<?, @Nullable Object> nullableValueEntry = (Entry<?, @Nullable Object>) entry;
      nullableValueEntry.setValue(null);
      fail("setValue on unmodifiable Map.Entry succeeded");
    } catch (UnsupportedOperationException expected) {
    }
  }

  /**
   * Verifies that an Iterator is unmodifiable.
   *

                if (beanDesc.hasPropertyDesc(propertyName)) {
                    final PropertyDesc propertyDesc = beanDesc.getPropertyDesc(propertyName);
                    propertyDesc.setValue(closeableHttpClient, entry.getValue());
                } else {
                    logger.warn("DefaultHttpClient does not have {}.", propertyName);
                }
            }
        }

   * Returns a map view that associates each key with the corresponding values in the multimap.
   * Changes to the returned map, such as element removal, will update the underlying multimap. The
   * map does not support {@code setValue()} on its entries, {@code put}, or {@code putAll}.
   *
   * <p>When passed a key that is present in the map, {@code asMap().get(Object)} has the same

      int entryIndex, @ParametricNullness K key, @ParametricNullness V value, int hash, int mask) {
    this.setEntry(entryIndex, CompactHashing.maskCombine(hash, UNSET, mask));
    this.setKey(entryIndex, key);
    this.setValue(entryIndex, value);
  }

  /** Resizes the entries storage if necessary. */
  private void resizeMeMaybe(int newSize) {
    int entriesSize = requireEntries().length;
    if (newSize > entriesSize) {

    assertThrows(UnsupportedOperationException.class, () -> map.putAll(ImmutableMap.of("b", "2")));

    assertThrows(
        UnsupportedOperationException.class,
        () -> map.entrySet().iterator().next().setValue("one"));
  }

  public void testTransformRemoveEntry() {
    Map<String, Integer> underlying = new HashMap<>();
    underlying.put("a", 1);

    filtered.put("b", 4);
    assertEquals(ImmutableMap.of("a", 2, "b", 4), filtered);

    Entry<String, Integer> entry = filtered.entrySet().iterator().next();
    assertThrows(IllegalArgumentException.class, () -> entry.setValue(5));

    assertEquals(ImmutableMap.of("a", 2, "b", 4), filtered);
  }

  public void testFilteredValuesClear() {
    Map<String, Integer> unfiltered = createUnfiltered();
    unfiltered.put("one", 1);

    assertThrows(UnsupportedOperationException.class, () -> map.putAll(ImmutableMap.of("b", "2")));

    assertThrows(
        UnsupportedOperationException.class,
        () -> map.entrySet().iterator().next().setValue("one"));
  }

  public void testTransformRemoveEntry() {
    Map<String, Integer> underlying = new HashMap<>();
    underlying.put("a", 1);

     *
     * @param index
     *            the index
     * @param value
     *            the value
     */
    public void setAt(final int index, final V value) {
        getEntryAt(index).setValue(value);
    }

    @Override
    public V remove(final Object key) {
        final Entry<K, V> e = removeMap(key);
        if (e != null) {
            final V value = e.value;

    Set<Entry<K, V>> es = entrySet;
    return (es != null) ? es : (entrySet = new EntrySet(this));
  }

  /**
   * Custom Entry class used by EntryIterator.next(), that relays setValue changes to the underlying
   * map.
   */
  private final class WriteThroughEntry implements Entry<K, V> {
    final K key;
    V value;

    WriteThroughEntry(K key, V value) {