new ClassValue<Boolean>() {
            @Override
            protected Boolean computeValue(Class<?> type) {
              checkExceptionClassValidity(type.asSubclass(Exception.class));
              return true;
            }
          };

      @Override
      public void validateClass(Class<? extends Exception> exceptionClass) {

    Preconditions.checkArgument(hitRate >= 0 && hitRate <= 1, "hitRate must be in the range [0,1]");

    enumType =
        Class.forName(EnumsBenchmark.class.getCanonicalName() + "$" + enumSize + "Enum")
            .asSubclass(Enum.class);

    Enum<?>[] allConstants = enumType.getEnumConstants();
    List<String> hits = new ArrayList<>();
    for (int i = 0; i < hitRate * 256 / 3; ++i) {
      hits.add(allConstants[0].name());

    Preconditions.checkArgument(hitRate >= 0 && hitRate <= 1, "hitRate must be in the range [0,1]");

    enumType =
        Class.forName(EnumsBenchmark.class.getCanonicalName() + "$" + enumSize + "Enum")
            .asSubclass(Enum.class);

    Enum<?>[] allConstants = enumType.getEnumConstants();
    List<String> hits = new ArrayList<>();
    for (int i = 0; i < hitRate * 256 / 3; ++i) {
      hits.add(allConstants[0].name());

  public void testSubtypeOfInnerClass_nonStaticAnonymousClass() {
    TypeToken<?> supertype = new TypeToken<Mall<Outdoor>.Shop<Electronics>>() {};
    Class<?> subclass = new Mall<Outdoor>().new Shop<Electronics>() {}.getClass();
    assertTrue(TypeToken.of(subclass).isSubtypeOf(supertype));
  }

  @SuppressWarnings("RestrictedApiChecker") // crashes under JDK8, which EP no longer supports

This simple case is handled automatically by FastAPI because the return type annotation is the class (or a subclass of) `Response`.

And tools will also be happy because both `RedirectResponse` and `JSONResponse` are subclasses of `Response`, so the type annotation is correct.

### Annotate a Response Subclass

You can also use a subclass of `Response` in the type annotation:

```Python hl_lines="8-9"

              public void remove() {
                throw new IllegalStateException() {
                  /* subclass */
                };
              }

              @Override
              public Integer next() {
                throw new NoSuchElementException() {
                  /* subclass */
                };
              }

              @Override
              public boolean hasNext() {

   * {@link ForwardingMap#entrySet}. In many cases, you may wish to override {@link
   * ForwardingMap#keySet} to forward to this implementation or a subclass thereof.
   *
   * @since 10.0
   */
  protected class StandardKeySet extends Maps.KeySet<K, V> {
    /** Constructor for use by subclasses. */
    public StandardKeySet() {
      super(ForwardingMap.this);

              public void remove() {
                throw new IllegalStateException() {
                  /* subclass */
                };
              }

              @Override
              public Integer next() {
                throw new NoSuchElementException() {
                  /* subclass */
                };
              }

              @Override
              public boolean hasNext() {

   * already complete, we would not initialize the subclass before calling {@link
   * #collectValueFromNonCancelledFuture}. As this is called after the subclass is constructed,
   * we're guaranteed to have properly initialized the subclass.
   */
  final void init() {
    /*

But if you return a `Response` directly (or any subclass, like `JSONResponse`), the data won't be automatically converted (even if you declare a `response_model`), and the documentation won't be automatically generated (for example, including the specific "media type", in the HTTP header `Content-Type` as part of the generated OpenAPI).