private static final class AlwaysEqual extends Ordering<@Nullable Object>
      implements Serializable {
    private static final AlwaysEqual INSTANCE = new AlwaysEqual();

    @Override
    @SuppressWarnings("UnusedVariable") // intentionally weird Comparator
    public int compare(@Nullable Object o1, @Nullable Object o2) {
      return 0;
    }

    @Override

@GwtIncompatible
@J2ktIncompatible
interface ReferenceEntry<K, V> {
  /** Returns the value reference from this entry. */
  @Nullable ValueReference<K, V> getValueReference();

  /** Sets the value reference for this entry. */
  void setValueReference(ValueReference<K, V> valueReference);

  /** Returns the next entry in the chain. */
  @Nullable ReferenceEntry<K, V> getNext();

  /** Returns the entry's hash. */
  int getHash();

import java.util.Set;
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

/**
 * Creates map entries using sample keys and sample values.
 *
 * @author Jesse Wilson
 */
@GwtCompatible
@NullMarked
public abstract class TestMapEntrySetGenerator<
        K extends @Nullable Object, V extends @Nullable Object>
    implements TestSetGenerator<Map.Entry<K, V>> {
  private final SampleElements<K> keys;

 * @since 9.0 (in 1.0 as {@code ValueFuture})
 */
@GwtCompatible
public final class SettableFuture<V extends @Nullable Object>
    extends AbstractFuture.TrustedFuture<V> {
  /**
   * Creates a new {@code SettableFuture} that can be completed or cancelled by a later method call.
   */
  public static <V extends @Nullable Object> SettableFuture<V> create() {
    return new SettableFuture<>();
  }

  @CanIgnoreReturnValue
  @Override

    boolean contains(@Nonnull Version version);

    /**
     * Returns the upper boundary of this range, or {@code null} if none.
     */
    @Nullable
    Boundary getUpperBoundary();

    /**
     * Returns the lower boundary of this range, or {@code null} if none.
     */
    @Nullable
    Boundary getLowerBoundary();

    /**
     * {@return the string representation of this version}
     */
    @Nonnull
    @Override

import com.google.common.annotations.J2ktIncompatible;
import java.util.AbstractList;
import java.util.List;
import java.util.ListIterator;
import java.util.RandomAccess;
import org.jspecify.annotations.Nullable;

/**
 * Implementation of {@link Lists#cartesianProduct(List)}.
 *
 * @author Louis Wasserman
 */
@GwtCompatible
final class CartesianList<E> extends AbstractList<List<E>> implements RandomAccess {

 * "https://github.com/google/guava/wiki/NewCollectionTypesExplained#multimap">{@code Multimap}</a>.
 *
 * @author Jared Levy
 * @since 2.0
 */
@GwtCompatible
public interface SortedSetMultimap<K extends @Nullable Object, V extends @Nullable Object>
    extends SetMultimap<K, V> {
  // Following Javadoc copied from Multimap.

  /**
   * Returns a collection view of all values associated with a key. If no mappings in the multimap

    IntegerDomain() {
      super(true);
    }

    @Override
    public @Nullable Integer next(Integer value) {
      int i = value;
      return (i == Integer.MAX_VALUE) ? null : i + 1;
    }

    @Override
    public @Nullable Integer previous(Integer value) {
      int i = value;
      return (i == Integer.MIN_VALUE) ? null : i - 1;
    }

    @Override

import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

/**
 * To be implemented by test generators that can produce test subjects without requiring any
 * parameters.
 *
 * @param <T> the type created by this generator.
 * @author George van den Driessche
 */
@GwtCompatible
@NullMarked
public interface TestSubjectGenerator<T extends @Nullable Object> {
  T createTestSubject();

import java.util.Queue;
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

/**
 * Creates queues, containing sample elements, to be tested.
 *
 * @author Jared Levy
 */
@GwtCompatible
@NullMarked
public interface TestQueueGenerator<E extends @Nullable Object> extends TestCollectionGenerator<E> {
  @Override
  Queue<E> create(Object... elements);