public void testWildcardFuture() {
    SettableFuture<String> settable = SettableFuture.create();
    ListenableFuture<?> f = settable;
    FutureCallback<@Nullable Object> callback =
        new FutureCallback<@Nullable Object>() {
          @Override
          public void onSuccess(@Nullable Object result) {}

          @Override
          public void onFailure(Throwable t) {}
        };
    addCallback(f, callback, directExecutor());

 * footprint.
 */
@GwtCompatible
@NullMarked
final class ObjectCountLinkedHashMap<K extends @Nullable Object> extends ObjectCountHashMap<K> {
  /** Creates an empty {@code ObjectCountLinkedHashMap} instance. */
  static <K extends @Nullable Object> ObjectCountLinkedHashMap<K> create() {
    return new ObjectCountLinkedHashMap<K>();
  }

  /**

    E[] castedArray = (E[]) array;
    return Arrays.asList(castedArray);
  }

  @Override
  public int indexOf(@Nullable Object object) {
    return (object == null) ? -1 : Lists.indexOfImpl(this, object);
  }

  @Override
  public int lastIndexOf(@Nullable Object object) {
    return (object == null) ? -1 : Lists.lastIndexOfImpl(this, object);
  }

  @Override

import java.util.Comparator;
import java.util.Map;
import java.util.Map.Entry;
import java.util.function.Function;
import java.util.stream.Collector;
import java.util.stream.Stream;
import org.jspecify.annotations.Nullable;

/**
 * A {@link ListMultimap} whose contents will never change, with many other important properties
 * detailed at {@link ImmutableCollection}.
 *
 * <p>See the Guava User Guide article on <a href=

   * java.util.Objects#equals} instead.
   */
  @SuppressWarnings("InlineMeSuggester") // would introduce fully qualified references to Objects
  public static boolean equal(@Nullable Object a, @Nullable Object b) {
    return java.util.Objects.equals(a, b);
  }

  /**
   * Generates a hash code for multiple values. The hash code is generated by calling {@link

import java.util.Iterator;
import java.util.List;
import java.util.Set;
import java.util.Spliterator;
import java.util.function.Consumer;
import java.util.function.ObjIntConsumer;
import org.jspecify.annotations.Nullable;

/**
 * A collection that supports order-independent equality, like {@link Set}, but may have duplicate
 * elements. A multiset is also sometimes called a <i>bag</i>.
 *

   * as well.
   */
  @Override
  public abstract ImmutableMap<R, Map<C, V>> rowMap();

  @Override
  public boolean contains(@Nullable Object rowKey, @Nullable Object columnKey) {
    return get(rowKey, columnKey) != null;
  }

  @Override
  public boolean containsValue(@Nullable Object value) {
    return values().contains(value);
  }

  /**
   * Guaranteed to throw an exception and leave the table unmodified.

import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
import org.jspecify.annotations.Nullable;

/** Methods factored out so that they can be emulated differently in GWT. */
@GwtCompatible
final class Platform {
  static boolean isInstanceOfThrowableClass(
      @Nullable Throwable t, Class<? extends Throwable> expectedClass) {
    return expectedClass.isInstance(t);
  }

import com.google.common.annotations.GwtCompatible;
import java.util.ArrayList;
import java.util.List;
import java.util.ListIterator;
import org.jspecify.annotations.NullMarked;
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

import com.google.common.annotations.GwtIncompatible;
import com.google.common.annotations.J2ktIncompatible;
import java.util.Collections;
import java.util.Set;
import org.jspecify.annotations.Nullable;

/**
 * Encapsulates the constraints that a class under test must satisfy in order for a tester method to
 * be run against that class.
 *
 * @author George van den Driessche
 */
@GwtCompatible