* @since 11.0
   */
  public static <R extends @Nullable Object, C extends @Nullable Object, V extends @Nullable Object>
      Table<R, C, V> unmodifiableTable(Table<? extends R, ? extends C, ? extends V> table) {
    return new UnmodifiableTable<>(table);
  }

  private static class UnmodifiableTable<
          R extends @Nullable Object, C extends @Nullable Object, V extends @Nullable Object>

            return Lists.transform(objs, OPTIONAL_TO_NULLABLE);
          }
        });
  }

  private CacheBuilder<Object, Object> createCacheBuilder(
      @Nullable Integer concurrencyLevel,
      @Nullable Integer initialCapacity,
      @Nullable Integer maximumSize,
      @Nullable DurationSpec expireAfterWrite,
      @Nullable DurationSpec expireAfterAccess,
      @Nullable DurationSpec refresh,

   * applying {@code function} to the elements of {@code fromSpliterator}.
   */
  static <InElementT extends @Nullable Object, OutElementT extends @Nullable Object>
      Spliterator<OutElementT> flatMap(
          Spliterator<InElementT> fromSpliterator,
          Function<? super InElementT, @Nullable Spliterator<OutElementT>> function,
          int topCharacteristics,
          long topSize) {
    checkArgument(

  @CanIgnoreReturnValue // TODO(kak): consider removing this
  @Override
  public <T extends @Nullable Object> ListenableFuture<T> submit(
      Runnable task, @ParametricNullness T result) {
    return (ListenableFuture<T>) super.submit(task, result);
  }

  @CanIgnoreReturnValue // TODO(kak): consider removing this
  @Override
  public <T extends @Nullable Object> ListenableFuture<T> submit(Callable<T> task) {

    - [Other notable changes](#other-notable-changes)
- [v1.15.7](#v1157)
  - [Downloads for v1.15.7](#downloads-for-v1157)
    - [Client Binaries](#client-binaries-5)
    - [Server Binaries](#server-binaries-5)
    - [Node Binaries](#node-binaries-5)
  - [Changelog since v1.15.6](#changelog-since-v1156)
    - [Other notable changes](#other-notable-changes-1)
- [v1.15.6](#v1156)

    Callable<@Nullable Void> cancelRunnable =
        new Callable<@Nullable Void>() {
          @Override
          public @Nullable Void call() {
            cancellationSuccess.set(currentFuture.get().cancel(true));
            awaitUnchecked(barrier);
            return null;
          }
        };
    Callable<@Nullable Void> setFutureCompleteSuccessfullyRunnable =

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) {

public final class CollectorTester<
    T extends @Nullable Object, A extends @Nullable Object, R extends @Nullable Object> {
  /**
   * Creates a {@code CollectorTester} for the specified {@code Collector}. The result of the {@code
   * Collector} will be compared to the expected value using {@link Object#equals}.
   */
  public static <T extends @Nullable Object, A extends @Nullable Object, R extends @Nullable Object>

                return (from == null) ? true : null;
              }
            });

    Set<Entry<@Nullable String, @Nullable Boolean>> entries = map.entrySet();
    assertTrue(entries.contains(Maps.immutableEntry("a", true)));
    assertTrue(entries.contains(Maps.<String, @Nullable Boolean>immutableEntry("b", null)));
    assertTrue(

  @Override
  public <S extends Comparable<?>> Ordering<@Nullable S> nullsFirst() {
    Ordering<@Nullable Comparable<?>> result = nullsFirst;
    if (result == null) {
      result = nullsFirst = super.<Comparable<?>>nullsFirst();
    }
    return (Ordering<@Nullable S>) result;
  }

  @Override
  public <S extends Comparable<?>> Ordering<@Nullable S> nullsLast() {
    Ordering<@Nullable Comparable<?>> result = nullsLast;