import org.jspecify.annotations.Nullable;

/**
 * A mutable value of type {@code int}, for multisets to use in tracking counts of values.
 *
 * @author Louis Wasserman
 */
@GwtCompatible
final class Count implements Serializable {
  private int value;

  Count(int value) {
    this.value = value;
  }

  public int get() {
    return value;
  }

  public void add(int delta) {
    value += delta;
  }

import org.jspecify.annotations.Nullable;

/**
 * Simple base class to verify that we handle generics correctly.
 *
 * @author Kevin Bourrillion
 */
@GwtCompatible
public class BaseComparable implements Comparable<BaseComparable>, Serializable {
  private final String s;

  public BaseComparable(String s) {
    this.s = s;
  }

  @Override
  public int hashCode() { // delegate to 's'

 * Optional features of classes derived from {@code Set}.
 *
 * @author George van den Driessche
 */
@SuppressWarnings("rawtypes") // maybe avoidable if we rework the whole package?
@GwtCompatible
public enum SetFeature implements Feature<Set> {
  GENERAL_PURPOSE(CollectionFeature.GENERAL_PURPOSE);

  private final Set<Feature<? super Set>> implied;

  SetFeature(Feature<? super Set>... implied) {
    this.implied = copyToSet(implied);
  }

 *
 * @author Louis Wasserman
 */
@GwtCompatible
abstract class TransformedIterator<F extends @Nullable Object, T extends @Nullable Object>
    implements Iterator<T> {
  final Iterator<? extends F> backingIterator;

  TransformedIterator(Iterator<? extends F> backingIterator) {
    this.backingIterator = checkNotNull(backingIterator);
  }

  @ParametricNullness

import org.jspecify.annotations.NullMarked;

/**
 * Create string sets for collection tests.
 *
 * @author Kevin Bourrillion
 */
@GwtCompatible
@NullMarked
public abstract class TestStringSetGenerator implements TestSetGenerator<String> {
  @Override
  public SampleElements<String> samples() {
    return new Strings();
  }

  @Override
  public Set<String> create(Object... elements) {

import java.io.Serializable;
import java.util.Iterator;
import org.jspecify.annotations.Nullable;

@GwtCompatible
final class PairwiseEquivalence<E, T extends @Nullable E> extends Equivalence<Iterable<T>>
    implements Serializable {
  final Equivalence<E> elementEquivalence;

  PairwiseEquivalence(Equivalence<E> elementEquivalence) {
    this.elementEquivalence = Preconditions.checkNotNull(elementEquivalence);
  }

  @Override

 *
 * @author Luke Sandberg
 */
@J2ktIncompatible
@GwtIncompatible
abstract class WrappingScheduledExecutorService extends WrappingExecutorService
    implements ScheduledExecutorService {
  final ScheduledExecutorService delegate;

  protected WrappingScheduledExecutorService(ScheduledExecutorService delegate) {
    super(delegate);
    this.delegate = delegate;
  }

 *
 * @author Isaac Shum
 * @since 10.0
 */
@J2ktIncompatible
@GwtIncompatible
public abstract class ForwardingListeningExecutorService extends ForwardingExecutorService
    implements ListeningExecutorService {
  /** Constructor for use by subclasses. */
  protected ForwardingListeningExecutorService() {}

  @Override
  protected abstract ListeningExecutorService delegate();

  @Override

 * Negotiation Protocol) authentication. It contains the username extracted from the
 * SPNEGO authentication process, typically from a Kerberos ticket.
 */
public class SpnegoCredential implements LoginCredential, FessCredential {

    /** The username extracted from SPNEGO authentication. */
    private final String username;

    /**
     * Constructs a new SpnegoCredential with the specified username.

/**
 * Generates {@code List<Character>} instances for test suites.
 *
 * @author Kevin Bourrillion
 * @author Louis Wasserman
 */
@GwtCompatible
@NullMarked
public abstract class TestCharacterListGenerator implements TestListGenerator<Character> {
  @Override
  public SampleElements<Character> samples() {
    return new Chars();
  }

  @Override
  public List<Character> create(Object... elements) {