private static final Iterable<@Nullable Integer> iterableNull = Arrays.asList((Integer) null);
  private static final Iterable<@Nullable Integer> iterableNullNull =
      Arrays.asList((Integer) null, null);
  private static final Iterable<@Nullable Integer> iterableNull1 = Arrays.asList(null, 1);
  private static final Iterable<@Nullable Integer> iterable1Null = Arrays.asList(1, null);

import org.jspecify.annotations.Nullable;

/**
 * Derived suite generators for Guava collection interfaces, split out of the suite builders so that
 * they are available to GWT.
 *
 * @author Louis Wasserman
 */
@GwtCompatible
@NullMarked
public final class DerivedGoogleCollectionGenerators {
  public static class MapGenerator<K extends @Nullable Object, V extends @Nullable Object>

      assertTrue(Thread.holdsLock(mutex));
      return delegate.removeLast();
    }

    @Override
    public @Nullable E pollFirst() {
      assertTrue(Thread.holdsLock(mutex));
      return delegate.pollFirst();
    }

    @Override
    public @Nullable E pollLast() {
      assertTrue(Thread.holdsLock(mutex));
      return delegate.pollLast();
    }

    @Override

                    @Nonnull Session session,
                    @Nullable RequestTrace trace,
                    @Nullable Path path,
                    @Nullable Source source,
                    boolean allowStubModel,
                    boolean recursive,
                    boolean processPlugins,
                    @Nullable List<RemoteRepository> repositories) {
                super(session, trace);

 */
public abstract class LookupInvoker<C extends LookupContext> implements Invoker {
    protected final Lookup protoLookup;

    @Nullable
    protected final Consumer<LookupContext> contextConsumer;

    public LookupInvoker(Lookup protoLookup, @Nullable Consumer<LookupContext> contextConsumer) {
        this.protoLookup = requireNonNull(protoLookup);
        this.contextConsumer = contextConsumer;
    }

  private final boolean hasLowerBound;
  private final @Nullable T lowerEndpoint;
  private final BoundType lowerBoundType;
  private final boolean hasUpperBound;
  private final @Nullable T upperEndpoint;
  private final BoundType upperBoundType;

  private GeneralRange(
      Comparator<? super T> comparator,
      boolean hasLowerBound,
      @Nullable T lowerEndpoint,
      BoundType lowerBoundType,

    public @Nullable E higher(@ParametricNullness E e) {
      return delegate.higher(e);
    }

    @Override
    public @Nullable E pollFirst() {
      throw new UnsupportedOperationException();
    }

    @Override
    public @Nullable E pollLast() {
      throw new UnsupportedOperationException();
    }

    @LazyInit private transient @Nullable UnmodifiableNavigableSet<E> descendingSet;

 * @author George van den Driessche
 */
@GwtCompatible
@NullMarked
public class AbstractTester<G> extends TestCase {
  private G subjectGenerator;
  private String suiteName;
  private @Nullable Runnable setUp;
  private @Nullable Runnable tearDown;

  // public so that it can be referenced in generated GWT tests.
  @Override
  public void setUp() throws Exception {
    if (setUp != null) {
      setUp.run();
    }
  }

 * @author George van den Driessche
 */
@GwtCompatible
@NullMarked
public class AbstractTester<G> extends TestCase {
  private G subjectGenerator;
  private String suiteName;
  private @Nullable Runnable setUp;
  private @Nullable Runnable tearDown;

  // public so that it can be referenced in generated GWT tests.
  @Override
  public void setUp() throws Exception {
    if (setUp != null) {
      setUp.run();
    }
  }

      new IteratorOperation() {
        @Override
        public @Nullable Object execute(Iterator<?> iterator) {
          iterator.remove();
          return null;
        }
      };

  private static final IteratorOperation NEXT_METHOD =
      new IteratorOperation() {
        @Override
        public @Nullable Object execute(Iterator<?> iterator) {
          return iterator.next();
        }