* AbstractMapBasedMultimap} calls {@link #createCollection()} to create the collection of values
 * for that key. The subclass should not call {@link #createCollection()} directly, and a new
 * instance should be created every time the method is called.
 *
 * <p>For example, the subclass could pass a {@link java.util.TreeMap} during construction, and

 * subclasses. Without such overrides, optimizers might put a {@code writeReplace}-containing class
 * and its subclass in different packages, causing the serialization system to fail to invoke {@code
 * writeReplace} when serializing an instance of the subclass. For an example of this problem, see
 * b/310253115.
 */
@NullUnmarked
public class WriteReplaceOverridesTest extends TestCase {

   * {@link ForwardingMap#entrySet}. In many cases, you may wish to override {@link
   * ForwardingMap#keySet} to forward to this implementation or a subclass thereof.
   *
   * @since 10.0
   */
  protected class StandardKeySet extends Maps.KeySet<K, V> {
    /** Constructor for use by subclasses. */
    public StandardKeySet() {
      super(ForwardingMap.this);

    private static ClassOwnership detectJvmBehavior() {
      class LocalClass<T> {}
      Class<?> subclass = new LocalClass<String>() {}.getClass();
      // requireNonNull is safe because we're examining a type that's known to have a superclass.
      ParameterizedType parameterizedType =
          requireNonNull((ParameterizedType) subclass.getGenericSuperclass());
      for (ClassOwnership behavior : ClassOwnership.values()) {

package com.google.common.graph;

import static com.google.common.base.Preconditions.checkNotNull;

import com.google.common.base.Supplier;
import com.google.common.collect.ForwardingSet;
import java.util.Set;

/**
 * A subclass of `ForwardingSet` that throws `IllegalStateException` on invocation of any method
 * (except `hashCode` and `equals`) if the provided `Supplier` returns false.
 */
final class InvalidatableSet<E> extends ForwardingSet<E> {

              public void remove() {
                throw new IllegalStateException() {
                  /* subclass */
                };
              }

              @Override
              public Integer next() {
                throw new NoSuchElementException() {
                  /* subclass */
                };
              }

              @Override
              public boolean hasNext() {

import org.jspecify.annotations.Nullable;

/**
 * A utility similar to {@link IteratorTester} for testing a {@link ListIterator} against a known
 * good reference implementation. As with {@code IteratorTester}, a concrete subclass must provide
 * target iterators on demand. It also requires three additional constructor parameters: {@code
 * elementsToInsert}, the elements to be passed to {@code set()} and {@code add()} calls; {@code

/**
 * {@link FluentFuture} that forwards all calls to a delegate.
 *
 * <h3>Extension</h3>
 *
 * If you want a class like {@code FluentFuture} but with extra methods, we recommend declaring your
 * own subclass of {@link ListenableFuture}, complete with a method like {@link #from} to adapt an
 * existing {@code ListenableFuture}, implemented atop a {@link ForwardingListenableFuture} that
 * forwards to that future and adds the desired methods.

   * {@link SortedMultiset#entrySet}, and {@link SortedMultiset#remove(Object, int)}. In many
   * situations, you may wish to override {@link SortedMultiset#elementSet} to forward to this
   * implementation or a subclass thereof.
   *
   * @since 15.0
   */
  protected class StandardElementSet extends SortedMultisets.NavigableElementSet<E> {
    /** Constructor for use by subclasses. */
    public StandardElementSet() {

 * href="http://en.wikipedia.org/wiki/Decorator_pattern">decorator pattern</a>.
 *
 * <p>This class does not implement {@link java.util.RandomAccess}. If the delegate supports random
 * access, the {@code ForwardingList} subclass should implement the {@code RandomAccess} interface.
 *
 * <p><b>Warning:</b> The methods of {@code ForwardingList} forward <b>indiscriminately</b> to the