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 { #annotate-a-response-subclass }

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

public class UserRoleLoginExceptionTest extends UnitFessTestCase {

    // Mock subclass of RootAction for testing generic type safety
    private static class TestAction extends RootAction {
        // Test subclass
    }

    // Another mock subclass for testing
    private static class AdminAction extends RootAction {
        // Test admin subclass
    }

    @Test
    public void test_constructor() {

  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

  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

   * {@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);

   * {@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);

   * 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() {
    /*

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

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

              @Override
              public boolean hasNext() {

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

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

              @Override
              public boolean hasNext() {

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).