*/
  public static <F extends @Nullable Object, T extends @Nullable Object> Collection<T> transform(
      Collection<F> fromCollection, Function<? super F, T> function) {
    return new TransformedCollection<>(fromCollection, function);
  }

  static class TransformedCollection<F extends @Nullable Object, T extends @Nullable Object>
      extends AbstractCollection<T> {

import java.util.Set;
import org.checkerframework.checker.nullness.qual.Nullable;

@GwtCompatible(emulated = true)
@ElementTypesAreNonnullByDefault
public class Helpers {
  // Clone of Objects.equal
  static boolean equal(@Nullable Object a, @Nullable Object b) {
    return a == b || (a != null && a.equals(b));
  }

  // Clone of Lists.newArrayList
  public static <E extends @Nullable Object> List<E> copyToList(Iterable<? extends E> elements) {

      new Predicate<@Nullable Integer>() {
        @Override
        public boolean apply(@Nullable Integer i) {
          throw new AssertionFailedError("This predicate should never have been evaluated");
        }
      };

  /** Instantiable predicate with reasonable hashCode() and equals() methods. */
  static class IsOdd implements Predicate<@Nullable Integer>, Serializable {

  @SuppressWarnings("unchecked")
  static <K extends @Nullable Object> Function<Entry<K, ?>, K> keyFunction() {
    return (Function) EntryFunction.KEY;
  }

  @SuppressWarnings("unchecked")
  static <V extends @Nullable Object> Function<Entry<?, V>, V> valueFunction() {
    return (Function) EntryFunction.VALUE;
  }

  static <K extends @Nullable Object, V extends @Nullable Object> Iterator<K> keyIterator(

      Callable<T> callable, ListeningExecutorService listeningExecutorService) {
    checkNotNull(callable);
    checkNotNull(listeningExecutorService);
    return () -> listeningExecutorService.submit(callable);
  }

  /**
   * Wraps the given callable such that for the duration of {@link Callable#call} the thread that is
   * running will have the given name.
   *

  @SuppressWarnings("unchecked")
  static <K extends @Nullable Object> Function<Entry<K, ?>, K> keyFunction() {
    return (Function) EntryFunction.KEY;
  }

  @SuppressWarnings("unchecked")
  static <V extends @Nullable Object> Function<Entry<?, V>, V> valueFunction() {
    return (Function) EntryFunction.VALUE;
  }

  static <K extends @Nullable Object, V extends @Nullable Object> Iterator<K> keyIterator(

    };
  }

  @Override
  public @Nullable Entry<K, V> firstEntry() {
    return delegate.firstEntry();
  }

  @Override
  public K firstKey() {
    return delegate.firstKey();
  }

  @Override
  public @Nullable Entry<K, V> floorEntry(K key) {
    return delegate.floorEntry(checkValid(key));
  }

  @Override
  public @Nullable K floorKey(K key) {

 * the License.
 */

package com.google.common.base;

import org.checkerframework.checker.nullness.qual.Nullable;

/** Holder for extra methods of {@code Objects} only in web. */
public abstract class ExtraObjectsMethodsForWeb {
  public static boolean equal(@Nullable String a, @Nullable String b) {
    return a == b;
  }

import java.util.Comparator;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/** An ordering for a pre-existing comparator. */
@GwtCompatible(serializable = true)
@ElementTypesAreNonnullByDefault
final class ComparatorOrdering<T extends @Nullable Object> extends Ordering<T>
    implements Serializable {
  final Comparator<T> comparator;

        .addEqualityGroup(
            LENGTH_EQUIVALENCE.<@Nullable String>wrap(null),
            LENGTH_EQUIVALENCE.<@Nullable String>wrap(null))
        .addEqualityGroup(Equivalence.equals().wrap("hello"))
        .addEqualityGroup(Equivalence.equals().<@Nullable Object>wrap(null))
        .testEquals();
  }

  public void testWrap_get() {
    String test = "test";