*
   * @since 33.4.0 (but since 21.0 in the JRE flavor)
   */
  @SuppressWarnings("NullableOptional") // Null passthrough is reasonable for type conversions
  @IgnoreJRERequirement // Users will use this only if they're already using Optional.
  public static <T> @Nullable Optional<T> fromJavaUtil(
      java.util.@Nullable Optional<T> javaUtilOptional) {

  // If users use this when they shouldn't, we hope that NewApi will catch subsequent Stream calls.
  @IgnoreJRERequirement
  public Stream<String> lines() throws IOException {
    BufferedReader reader = openBufferedStream();
    return reader.lines().onClose(() -> closeUnchecked(reader));
  }

  @IgnoreJRERequirement // helper for lines()
  /*

@Ignore("test runners must not instantiate and run this directly, only via suites we build")
// @Ignore affects the Android test runner, which respects JUnit 4 annotations on JUnit 3 tests.
@SuppressWarnings("JUnit4ClassUsedInJUnit3")
@IgnoreJRERequirement // We opt into library desugaring for our tests.
public class MapForEachTester<K, V> extends AbstractMapTester<K, V> {
  @CollectionFeature.Require(KNOWN_ORDER)
  public void testForEachKnownOrder() {

  /**
   * Adds the given values to the dataset. The stream will be completely consumed by this method.
   *
   * @param values a series of values
   * @since 33.4.0 (but since 28.2 in the JRE flavor)
   */
  @IgnoreJRERequirement // Users will use this only if they're already using streams.
  public void addAll(DoubleStream values) {
    addAll(values.collect(StatsAccumulator::new, StatsAccumulator::add, StatsAccumulator::addAll));
  }

   * These are properties of the collection as a whole; SIZED and SUBSIZED are more properties of
   * the spliterator implementation.
   */
  // @IgnoreJRERequirement is not necessary because this compiles down to a constant.
  // (which is fortunate because Animal Sniffer doesn't look for @IgnoreJRERequirement on fields)
  static final int SPLITERATOR_CHARACTERISTICS =
      Spliterator.IMMUTABLE | Spliterator.NONNULL | Spliterator.ORDERED;

@Ignore("test runners must not instantiate and run this directly, only via suites we build")
// @Ignore affects the Android test runner, which respects JUnit 4 annotations on JUnit 3 tests.
@SuppressWarnings("JUnit4ClassUsedInJUnit3")
@IgnoreJRERequirement // We opt into library desugaring for our tests.
public class MapGetOrDefaultTester<K, V> extends AbstractMapTester<K, V> {
  @CollectionSize.Require(absent = ZERO)
  public void testGetOrDefault_present() {

@Ignore("test runners must not instantiate and run this directly, only via suites we build")
// @Ignore affects the Android test runner, which respects JUnit 4 annotations on JUnit 3 tests.
@SuppressWarnings("JUnit4ClassUsedInJUnit3")
@IgnoreJRERequirement // We opt into library desugaring for our tests.
public class MapReplaceAllTester<K, V> extends AbstractMapTester<K, V> {
  private SampleElements<K> keys() {
    return new SampleElements<>(k0(), k1(), k2(), k3(), k4());

@Ignore("test runners must not instantiate and run this directly, only via suites we build")
// @Ignore affects the Android test runner, which respects JUnit 4 annotations on JUnit 3 tests.
@SuppressWarnings("JUnit4ClassUsedInJUnit3")
@IgnoreJRERequirement // We opt into library desugaring for our tests.
public class MapReplaceTester<K, V> extends AbstractMapTester<K, V> {

  @MapFeature.Require(SUPPORTS_PUT)
  @CollectionSize.Require(absent = ZERO)

@Ignore("test runners must not instantiate and run this directly, only via suites we build")
// @Ignore affects the Android test runner, which respects JUnit 4 annotations on JUnit 3 tests.
@SuppressWarnings("JUnit4ClassUsedInJUnit3")
@IgnoreJRERequirement // We opt into library desugaring for our tests.
public class CollectionRemoveIfTester<E> extends AbstractCollectionTester<E> {
  @CollectionFeature.Require(SUPPORTS_ITERATOR_REMOVE)
  public void testRemoveIf_alwaysFalse() {

@Ignore("test runners must not instantiate and run this directly, only via suites we build")
// @Ignore affects the Android test runner, which respects JUnit 4 annotations on JUnit 3 tests.
@SuppressWarnings("JUnit4ClassUsedInJUnit3")
@IgnoreJRERequirement // We opt into library desugaring for our tests.
public class MapComputeIfPresentTester<K, V> extends AbstractMapTester<K, V> {

  @MapFeature.Require(SUPPORTS_PUT)
  public void testComputeIfPresent_supportedAbsent() {