* @return The interpolated string, or null if the input was null.
     */
    @Nullable
    String interpolate(
            @Nullable String val,
            @Nullable UnaryOperator<String> callback,
            @Nullable BinaryOperator<String> postprocessor,
            boolean defaultsToEmpty);

    /**

  @SuppressWarnings("NullableOptional") // Null passthrough is reasonable for type conversions
  @IgnoreJRERequirement // Users will use this only if they're already using Optional.
  public static <T> @Nullable Optional<T> fromJavaUtil(
      java.util.@Nullable Optional<T> javaUtilOptional) {
    return (javaUtilOptional == null) ? null : fromNullable(javaUtilOptional.orElse(null));
  }

  /**

      }
    };
  }

  @LazyInit private transient @Nullable ImmutableList<E> asList;

  @Override
  public ImmutableList<E> asList() {
    ImmutableList<E> result = asList;
    return (result == null) ? asList = super.asList() : result;
  }

  @Override
  public boolean contains(@Nullable Object object) {
    return count(object) > 0;
  }

  /**

  }

  static boolean patternCompilerIsPcreLike() {
    throw new UnsupportedOperationException();
  }

  static String lenientFormat(@Nullable String template, @Nullable Object @Nullable ... args) {
    return Strings.lenientFormat(template, args);
  }

  static String stringValueOf(@Nullable Object o) {
    return String.valueOf(o);
  }

  private Platform() {}

   * not have been inserted consecutively.
   */
  private final @Nullable List<NodeConnection<N>> orderedNodeConnections;

  private int predecessorCount;
  private int successorCount;

  private DirectedGraphConnections(
      Map<N, Object> adjacentNodeValues,
      @Nullable List<NodeConnection<N>> orderedNodeConnections,
      int predecessorCount,
      int successorCount) {

  @VisibleForTesting final transient @Nullable Object[] array;
  private final transient int size;

  RegularImmutableList(@Nullable Object[] array, int size) {
    this.array = array;
    this.size = size;
  }

  @Override
  public int size() {
    return size;
  }

  @Override
  boolean isPartialView() {
    return false;
  }

  @Override
  @Nullable Object[] internalArray() {
    return array;

import java.util.Iterator;
import java.util.Map.Entry;
import java.util.Objects;
import org.jspecify.annotations.Nullable;

/**
 * Implementation for {@link FilteredMultimap#values()}.
 *
 * @author Louis Wasserman
 */
@GwtCompatible
final class FilteredMultimapValues<K extends @Nullable Object, V extends @Nullable Object>
    extends AbstractCollection<V> {
  @Weak private final FilteredMultimap<K, V> multimap;

  @CanIgnoreReturnValue
  @Override
  public @Nullable V putIfAbsent(K key, V value) {
    return delegate().putIfAbsent(key, value);
  }

  @CanIgnoreReturnValue
  @Override
  public boolean remove(@Nullable Object key, @Nullable Object value) {
    return delegate().remove(key, value);
  }

  @CanIgnoreReturnValue
  @Override
  public @Nullable V replace(K key, V value) {

   */

  static final class Node<K extends @Nullable Object, V extends @Nullable Object>
      extends SimpleEntry<K, V> {
    @Nullable Node<K, V> next; // the next node (with any key)
    @Weak @Nullable Node<K, V> previous; // the previous node (with any key)
    @Nullable Node<K, V> nextSibling; // the next node with the same key
    @Weak @Nullable Node<K, V> previousSibling; // the previous node with the same key

@GwtCompatible
public abstract class ForwardingSet<E extends @Nullable Object> extends ForwardingCollection<E>
    implements Set<E> {
  // TODO(lowasser): identify places where thread safety is actually lost

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

  @Override
  protected abstract Set<E> delegate();

  @Override
  public boolean equals(@Nullable Object object) {