}

  public void testNullFriendlyTransform() {
    Iterator<@Nullable Integer> input = Arrays.<@Nullable Integer>asList(1, 2, null, 3).iterator();
    Iterator<String> result =
        Iterators.transform(
            input,
            new Function<@Nullable Integer, String>() {
              @Override
              public String apply(@Nullable Integer from) {
                return String.valueOf(from);
              }

  @Override
  public E takeLast() throws InterruptedException {
    return delegate().takeLast();
  }

  @Override
  public @Nullable E pollFirst(long timeout, TimeUnit unit) throws InterruptedException {
    return delegate().pollFirst(timeout, unit);
  }

  @Override
  public @Nullable E pollLast(long timeout, TimeUnit unit) throws InterruptedException {
    return delegate().pollLast(timeout, unit);
  }

  @Override

   *
   * <p>The serialized output consists of the number of entries, first key, first value, second key,
   * second value, and so on.
   */
  static <K extends @Nullable Object, V extends @Nullable Object> void writeMap(
      Map<K, V> map, ObjectOutputStream stream) throws IOException {
    stream.writeInt(map.size());
    for (Map.Entry<K, V> entry : map.entrySet()) {

    public static Object good(
        String a,
        int b,
        // oneConstantOnly doesn't matter since it's not nullable and can be only 1 value.
        @SuppressWarnings("unused") OneConstantEnum oneConstantOnly,
        // noConstant doesn't matter since it can only be null
        @SuppressWarnings("unused") @Nullable NoConstantEnum noConstant) {
      return new GoodEquals(a, b);
    }

    // instance method ignored

import java.io.ObjectOutputStream;
import java.util.HashMap;
import org.jspecify.annotations.Nullable;

/**
 * Multiset implementation backed by a {@link HashMap}.
 *
 * @author Kevin Bourrillion
 * @author Jared Levy
 * @since 2.0
 */
@GwtCompatible
public final class HashMultiset<E extends @Nullable Object> extends AbstractMapBasedMultiset<E> {

        header);
  }

  private static final class Reference<T> {
    private @Nullable T value;

    @Nullable T get() {
      return value;
    }

    void checkAndSet(@Nullable T expected, @Nullable T newValue) {
      if (value != expected) {
        throw new ConcurrentModificationException();
      }
      value = newValue;
    }

        return backingMap.size();
      }

      @Override
      public boolean contains(@Nullable Object key) {
        return containsKey(key);
      }
    };
  }

  // Internal methods (package-visible, but treat as only subclass-visible)

  @Nullable V getIfCached(@Nullable Object key) {
    Entry<K, V> entry = cacheEntry; // store local reference for thread-safety

   */

  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

import org.jspecify.annotations.Nullable;

/**
 * Test cases for {@link Tables#transformValues}.
 *
 * @author Jared Levy
 */
@GwtCompatible
@NullMarked
public class TablesTransformValuesTest extends AbstractTableTest<Character> {

  private static final Function<@Nullable String, @Nullable Character> FIRST_CHARACTER =
      new Function<@Nullable String, @Nullable Character>() {
        @Override

    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();
  }