case "bonus":
			// allow to change non-nullable to nullable
			if nullable, _ := columnType.Nullable(); !nullable {
				t.Fatalf("bonus's nullable should be true, bug got %t", nullable)
			}
		case "stock":
			// do not allow to change nullable to non-nullable
			if nullable, _ := columnType.Nullable(); !nullable {
				t.Fatalf("stock's nullable should be true, bug got %t", nullable)
			}
		}
	}
}

  private static class SynchronizedMultimap<K extends @Nullable Object, V extends @Nullable Object>
      extends SynchronizedObject implements Multimap<K, V> {
    transient @Nullable Set<K> keySet;
    transient @Nullable Collection<V> valuesCollection;
    transient @Nullable Collection<Map.Entry<K, V>> entries;
    transient @Nullable Map<K, Collection<V>> asMap;
    transient @Nullable Multiset<K> keys;

    @SuppressWarnings("unchecked")

  private static class SynchronizedMultimap<K extends @Nullable Object, V extends @Nullable Object>
      extends SynchronizedObject implements Multimap<K, V> {
    transient @Nullable Set<K> keySet;
    transient @Nullable Collection<V> valuesCollection;
    transient @Nullable Collection<Map.Entry<K, V>> entries;
    transient @Nullable Map<K, Collection<V>> asMap;
    transient @Nullable Multiset<K> keys;

    @SuppressWarnings("unchecked")

  private static class UnmodifiableMultimap<K extends @Nullable Object, V extends @Nullable Object>
      extends ForwardingMultimap<K, V> implements Serializable {
    final Multimap<K, V> delegate;
    @LazyInit transient @Nullable Collection<Entry<K, V>> entries;
    @LazyInit transient @Nullable Multiset<K> keys;
    @LazyInit transient @Nullable Set<K> keySet;
    @LazyInit transient @Nullable Collection<V> values;

   * @throws IllegalArgumentException if {@code size} is nonpositive
   */
  public static <T extends @Nullable Object>
      UnmodifiableIterator<List<@Nullable T>> paddedPartition(Iterator<T> iterator, int size) {
    return partitionImpl(iterator, size, true);
  }

  private static <T extends @Nullable Object> UnmodifiableIterator<List<@Nullable T>> partitionImpl(
      Iterator<T> iterator, int size, boolean pad) {
    checkNotNull(iterator);

     * @param <U> the type returned by the function
     */
    public interface ClosingFunction5<
        V1 extends @Nullable Object,
        V2 extends @Nullable Object,
        V3 extends @Nullable Object,
        V4 extends @Nullable Object,
        V5 extends @Nullable Object,
        U extends @Nullable Object> {
      /**
       * Applies this function to five inputs, or throws an exception if unable to do so.
       *

   * @return a future that provides a list of the results of the component futures
   * @since 10.0
   */
  @SafeVarargs
  public static <V extends @Nullable Object> ListenableFuture<List<V>> allAsList(
      ListenableFuture<? extends V>... futures) {
    ListenableFuture<List<@Nullable V>> nullable =
        new ListFuture<V>(ImmutableList.copyOf(futures), true);
    // allAsList ensures that it fills the output list with V instances.

    public @Nullable E higher(@ParametricNullness E e) {
      return delegate.higher(e);
    }

    @Override
    public @Nullable E pollFirst() {
      throw new UnsupportedOperationException();
    }

    @Override
    public @Nullable E pollLast() {
      throw new UnsupportedOperationException();
    }

    @LazyInit private transient @Nullable UnmodifiableNavigableSet<E> descendingSet;

    @Nullable Segment<K, V, E, S> currentSegment;
    @Nullable AtomicReferenceArray<E> currentTable;
    @Nullable E nextEntry;
    @Nullable WriteThroughEntry nextExternal;
    @Nullable WriteThroughEntry lastReturned;

    HashIterator() {
      nextSegmentIndex = segments.length - 1;
      nextTableIndex = -1;
      advance();
    }

    @Override
    public abstract T next();

  }

  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);
              }