TrustedListenableFutureTask<@Nullable Void> task =
          TrustedListenableFutureTask.create(command, null);
      ScheduledFuture<?> scheduled = delegate.schedule(task, delay, unit);
      return new ListenableScheduledTask<@Nullable Void>(task, scheduled);
    }

    @Override
    public <V extends @Nullable Object> ListenableScheduledFuture<V> schedule(

                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(

  @GwtCompatible(serializable = true)
  public static <T extends @Nullable Object> Predicate<T> alwaysTrue() {
    return ObjectPredicate.ALWAYS_TRUE.withNarrowedType();
  }

  /** Returns a predicate that always evaluates to {@code false}. */
  @GwtCompatible(serializable = true)
  public static <T extends @Nullable Object> Predicate<T> alwaysFalse() {
    return ObjectPredicate.ALWAYS_FALSE.withNarrowedType();
  }

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

/** Implementations of {@code Futures.transform*}. */
@GwtCompatible
@ElementTypesAreNonnullByDefault
@SuppressWarnings("nullness") // TODO(b/147136275): Remove once our checker understands & and |.
abstract class AbstractTransformFuture<
        I extends @Nullable Object, O extends @Nullable Object, F, T extends @Nullable Object>

   */
  public static <A extends @Nullable Object, B extends @Nullable Object, C extends @Nullable Object>
      Function<A, C> compose(Function<B, C> g, Function<A, ? extends B> f) {
    return new FunctionComposition<>(g, f);
  }

  private static class FunctionComposition<
          A extends @Nullable Object, B extends @Nullable Object, C extends @Nullable Object>
      implements Function<A, C>, Serializable {

    }

    @Override
    Map<R, @Nullable V> getValue(int index) {
      return new Column(index);
    }

    @Override
    Map<R, @Nullable V> setValue(int index, Map<R, @Nullable V> newValue) {
      throw new UnsupportedOperationException();
    }

    @Override
    @CheckForNull
    public Map<R, @Nullable V> put(C key, Map<R, @Nullable V> value) {
      throw new UnsupportedOperationException();

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) {

   * 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(

   * @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>

  @Generates
  static <K, V> Map<K, V> generateMap(@Nullable K key, @Nullable V value) {
    return generateHashdMap(key, value);
  }

  @Generates
  static <K, V> HashMap<K, V> generateHashdMap(@Nullable K key, @Nullable V value) {
    return generateLinkedHashMap(key, value);
  }

  @Generates
  static <K, V> LinkedHashMap<K, V> generateLinkedHashMap(@Nullable K key, @Nullable V value) {