*/
  @get:Synchronized
  @set:Synchronized
  var idleCallback: Runnable? = null

  private var executorServiceOrNull: ExecutorService? = null

  @get:JvmName("executorService")
  @get:Synchronized
  val executorService: ExecutorService
    get() {
      if (executorServiceOrNull == null) {
        executorServiceOrNull =
          ThreadPoolExecutor(
            0,
            Int.MAX_VALUE,

    Collection<E> elements = getSampleElements(getNumElements() - 1);
    elements.add(null);

    collection = getSubjectGenerator().create(elements.toArray());
    assertTrue(
        "A Set should equal any other Set containing the same elements,"
            + " even if some elements are null.",
        getSet().equals(MinimalSet.from(elements)));
  }

  @CollectionSize.Require(absent = CollectionSize.ZERO)

    SpliteratorTester.of(
            () ->
                CollectSpliterators.flatMap(
                    Arrays.spliterator(new String[] {"abc", "", "de", "f", "g", ""}),
                    (String str) -> str.isEmpty() ? null : charactersOf(str).spliterator(),
                    Spliterator.SIZED | Spliterator.DISTINCT | Spliterator.NONNULL,
                    7))
        .expect('a', 'b', 'c', 'd', 'e', 'f', 'g');
  }

 *       typically because the type forbids nullable type arguments: For example, {@code
 *       ImmutableList.get} returns {@code E}, but that value is never {@code null}. (Accordingly,
 *       {@code ImmutableList} is declared to forbid {@code ImmutableList<@Nullable String>}.)
 *   <li>methods whose return type is a type variable but which can return {@code null} regardless

    Collection<E> elements = getSampleElements(getNumElements() - 1);
    elements.add(null);

    collection = getSubjectGenerator().create(elements.toArray());
    assertTrue(
        "A Set should equal any other Set containing the same elements,"
            + " even if some elements are null.",
        getSet().equals(MinimalSet.from(elements)));
  }

  @CollectionSize.Require(absent = CollectionSize.ZERO)

  public void testEquals_otherListContainingNull() {
    List<E> other = new ArrayList<>(getSampleElements());
    other.set(other.size() / 2, null);
    assertFalse(
        "Two Lists should not be equal if exactly one of them has null at a given index.",
        getList().equals(other));
  }

  @CollectionSize.Require(absent = CollectionSize.ZERO)
  @CollectionFeature.Require(ALLOWS_NULL_VALUES)

 *       typically because the type forbids nullable type arguments: For example, {@code
 *       ImmutableList.get} returns {@code E}, but that value is never {@code null}. (Accordingly,
 *       {@code ImmutableList} is declared to forbid {@code ImmutableList<@Nullable String>}.)
 *   <li>methods whose return type is a type variable but which can return {@code null} regardless

        encPart.add(new DERTaggedObject(true, 2, new DEROctetString(encryptedData)));
        v.add(new DERTaggedObject(true, 3, new DERSequence(encPart)));

        if (unknownTag != null) {
            v.add(new DERTaggedObject(true, unknownTag, new DERGeneralString("unknown")));
        }

        return new DERSequence(v).getEncoded();
    }

    /**

  public void testContains_nullNotContainedButAllowed() {
    assertFalse("containsValue(null) should return false", getMap().containsValue(null));
  }

  @MapFeature.Require(absent = ALLOWS_NULL_VALUE_QUERIES)
  public void testContains_nullNotContainedAndUnsupported() {
    expectNullValueMissingWhenNullValuesUnsupported(
        "containsValue(null) should return false or throw");
  }

  @MapFeature.Require(ALLOWS_NULL_VALUES)

@GwtCompatible
// TODO(cpovirk): Make this final (but that may break Mockito spy calls).
class ImmediateFuture<V extends @Nullable Object> implements ListenableFuture<V> {
  static final ListenableFuture<?> NULL = new ImmediateFuture<@Nullable Object>(null);

  private static final LazyLogger log = new LazyLogger(ImmediateFuture.class);

  @ParametricNullness private final V value;

  ImmediateFuture(@ParametricNullness V value) {