runConcurrentTest(
        numberOfThreads,
        new Callable<@Nullable Void>() {
          @Override
          public @Nullable Void call() throws Exception {
            long unused = ticker.read();
            return null;
          }
        });

    assertEquals(incrementByNanos * numberOfThreads, ticker.read());
  }

  /** Runs {@code callable} concurrently {@code numberOfThreads} times. */

    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 =

     * @return the merged node
     */
    @Nullable
    static XmlNode merge(@Nullable XmlNode dominant, @Nullable XmlNode recessive) {
        return merge(dominant, recessive, null);
    }

    @Nullable
    static XmlNode merge(
            @Nullable XmlNode dominant, @Nullable XmlNode recessive, @Nullable Boolean childMergeOverride) {
        if (recessive == null) {
            return dominant;
        }

            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,

  }

  static <R extends @Nullable Object, C extends @Nullable Object, V extends @Nullable Object>
      Table<R, C, V> table(Table<R, C, V> table, @CheckForNull Object mutex) {
    return new SynchronizedTable<>(table, mutex);
  }

  static final class SynchronizedTable<
          R extends @Nullable Object, C extends @Nullable Object, V extends @Nullable Object>

    }

    @Nonnull
    static SettingsBuilderRequest build(
            @Nonnull Session session,
            @Nullable Source globalSettingsSource,
            @Nullable Source projectSettingsSource,
            @Nullable Source userSettingsSource) {
        return builder()
                .session(nonNull(session, "session cannot be null"))

                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(

  }

  private static final ImmutableSet<String> NULLABLE_ANNOTATION_SIMPLE_NAMES =
      ImmutableSet.of("CheckForNull", "Nullable", "NullableDecl", "NullableType");

  static boolean isNullable(Invokable<?, ?> invokable) {
    return NULLNESS_ANNOTATION_READER.isNullable(invokable);
  }

  static boolean isNullable(Parameter param) {

    Callable<@Nullable Void> callable =
        new Callable<@Nullable Void>() {
          @Override
          public @Nullable Void call() throws Exception {
            assertEquals(Thread.currentThread().getName(), newName.get());
            return null;
          }
        };
    Callables.threadRenaming(callable, newName).call();

    final SettableFuture<@Nullable Void> settableFuture = SettableFuture.create();
    ArrayList<ListenableFuture<@Nullable Void>> results = new ArrayList<>(50_001);
    results.add(
        serializer.submitAsync(
            new AsyncCallable<@Nullable Void>() {
              @Override
              public ListenableFuture<@Nullable Void> call() {
                return settableFuture;