@Override
    public boolean equals(@Nullable Object o) {
      return false;
    }

    @Override
    public int hashCode() {
      return super.hashCode();
    }
  }

  /** Test class that returns true if the test object is null */
  private static class InvalidEqualsNullObject {

    @Override
    public boolean equals(@Nullable Object o) {
      return o == this || o == null;
    }

    Multiset<N> adjacentNodes = getReference(adjacentNodesReference);
    if (adjacentNodes != null) {
      checkState(adjacentNodes.add(node));
    }
  }

  private static <T> @Nullable T getReference(@Nullable Reference<T> reference) {
    return (reference == null) ? null : reference.get();
  }

import java.util.Map.Entry;
import java.util.Set;
import org.jspecify.annotations.Nullable;

/**
 * Implementation of {@link Multimaps#filterKeys(SetMultimap, Predicate)}.
 *
 * @author Louis Wasserman
 */
@GwtCompatible
final class FilteredKeySetMultimap<K extends @Nullable Object, V extends @Nullable Object>
    extends FilteredKeyMultimap<K, V> implements FilteredSetMultimap<K, V> {

// @Ignore affects the Android test runner, which respects JUnit 4 annotations on JUnit 3 tests.
@SuppressWarnings("JUnit4ClassUsedInJUnit3")
@NullMarked
public class MultimapSizeTester<K extends @Nullable Object, V extends @Nullable Object>
    extends AbstractMultimapTester<K, V, Multimap<K, V>> {

  public void testSize() {
    int expectedSize = getNumElements();
    Multimap<K, V> multimap = multimap();

    }

    @Override
    public boolean offer(T o) {
      return standardOffer(o);
    }

    @Override
    public @Nullable T peek() {
      return standardPeek();
    }

    @Override
    public @Nullable T poll() {
      return standardPoll();
    }
  }

  @AndroidIncompatible // test-suite builders
  public static Test suite() {

    @Override
    public boolean equals(@Nullable Object o) {
      return false;
    }

    @Override
    public int hashCode() {
      return super.hashCode();
    }
  }

  /** Test class that returns true if the test object is null */
  private static class InvalidEqualsNullObject {

    @Override
    public boolean equals(@Nullable Object o) {
      return o == this || o == null;
    }

 *
 * @author Kurt Alfred Kluever
 * @since 3.0
 */
@GwtCompatible
public abstract class ForwardingSortedSetMultimap<
        K extends @Nullable Object, V extends @Nullable Object>
    extends ForwardingSetMultimap<K, V> implements SortedSetMultimap<K, V> {

  /** Constructor for use by subclasses. */
  protected ForwardingSortedSetMultimap() {}

  @Override

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;

import java.io.Serializable;
import java.util.Arrays;
import java.util.Comparator;
import org.jspecify.annotations.Nullable;

/** An ordering that tries several comparators in order. */
@GwtCompatible
final class CompoundOrdering<T extends @Nullable Object> extends Ordering<T>
    implements Serializable {
  final Comparator<? super T>[] comparators;

import com.google.common.annotations.GwtIncompatible;
import com.google.common.annotations.J2ktIncompatible;
import com.google.common.base.Preconditions;
import org.jspecify.annotations.Nullable;

/**
 * Implementation of {@link ImmutableSet} with exactly one element.
 *
 * @author Kevin Bourrillion
 * @author Nick Kralevich
 */
@GwtCompatible