assertNotNull(
        rootLocaleFormat("%s must be annotated with @TesterAnnotation.", annotationClass),
        annotationClass.getAnnotation(TesterAnnotation.class));
    final Retention retentionPolicy = annotationClass.getAnnotation(Retention.class);
    assertNotNull(
        rootLocaleFormat("%s must have a @Retention annotation.", annotationClass),
        retentionPolicy);
    assertEquals(

  final <T> T isSubtype(T sub) {
    Type returnType = method.getGenericReturnType();
    Type paramType = getOnlyParameterType();
    TestSubtype spec = method.getAnnotation(TestSubtype.class);
    assertWithMessage("%s is subtype of %s", paramType, returnType)
        .that(TypeToken.of(paramType).isSubtypeOf(returnType))
        .isTrue();

    assertNotNull(
        rootLocaleFormat("%s must be annotated with @TesterAnnotation.", annotationClass),
        annotationClass.getAnnotation(TesterAnnotation.class));
    final Retention retentionPolicy = annotationClass.getAnnotation(Retention.class);
    assertNotNull(
        rootLocaleFormat("%s must have a @Retention annotation.", annotationClass),
        retentionPolicy);
    assertEquals(

    return declaration;
  }

  @Override
  public boolean isAnnotationPresent(Class<? extends Annotation> annotationType) {
    return getAnnotation(annotationType) != null;
  }

  @Override
  @CheckForNull
  public <A extends Annotation> A getAnnotation(Class<A> annotationType) {
    checkNotNull(annotationType);
    for (Annotation annotation : annotations) {
      if (annotationType.isInstance(annotation)) {

  final <T> T isSubtype(T sub) {
    Type returnType = method.getGenericReturnType();
    Type paramType = getOnlyParameterType();
    TestSubtype spec = method.getAnnotation(TestSubtype.class);
    assertWithMessage("%s is subtype of %s", paramType, returnType)
        .that(TypeToken.of(paramType).isSubtypeOf(returnType))
        .isTrue();

   * Checks whether {@code method} is thread-safe, as indicated by the presence of the {@link
   * AllowConcurrentEvents} annotation.
   */
  private static boolean isDeclaredThreadSafe(Method method) {
    return method.getAnnotation(AllowConcurrentEvents.class) != null;
  }

  /**
   * Subscriber that synchronizes invocations of a method to ensure that only one thread may enter
   * the method at a time.
   */
  @VisibleForTesting

  /**
   * Returns the {@link Field} in which {@code enumValue} is defined. For example, to get the {@code
   * Description} annotation on the {@code GOLF} constant of enum {@code Sport}, use {@code
   * Enums.getField(Sport.GOLF).getAnnotation(Description.class)}.
   *
   * @since 12.0
   */
  @GwtIncompatible // reflection
  public static Field getField(Enum<?> enumValue) {
    Class<?>
        clazz = enumValue.getDeclaringClass();
    try {

  /**
   * Returns the {@link Field} in which {@code enumValue} is defined. For example, to get the {@code
   * Description} annotation on the {@code GOLF} constant of enum {@code Sport}, use {@code
   * Enums.getField(Sport.GOLF).getAnnotation(Description.class)}.
   *
   * @since 12.0
   */
  @GwtIncompatible // reflection
  public static Field getField(Enum<?> enumValue) {
    Class<?>
        clazz = enumValue.getDeclaringClass();
    try {

  }

  @Override
  @CheckForNull
  public final <A extends Annotation> A getAnnotation(Class<A> annotationClass) {
    return accessibleObject.getAnnotation(annotationClass);
  }

  @Override
  public final Annotation[] getAnnotations() {
    return accessibleObject.getAnnotations();
  }

  @Override
  public final Annotation[] getDeclaredAnnotations() {

            || containsNullable(invokable.getAnnotatedReturnType().getAnnotations());
        // TODO(cpovirk): Should we also check isNullableTypeVariable?
      }

      @Override
      boolean isNullable(Parameter param) {
        return FROM_DECLARATION_ANNOTATIONS_ONLY.isNullable(param)
            || containsNullable(param.getAnnotatedType().getAnnotations())
            || isNullableTypeVariable(param.getAnnotatedType().getType());