These handlers are in charge of returning the default JSON responses when you `raise` an `HTTPException` and when the request has invalid data.

You can override these exception handlers with your own.

### Override request validation exceptions { #override-request-validation-exceptions }

When a request contains invalid data, **FastAPI** internally raises a `RequestValidationError`.

And it also includes a default exception handler for it.

                .orElseThrow(() -> new SsoMessageException(
                        messages -> messages.addErrorsFailedToProcessSsoRequest(UserMessages.GLOBAL_PROPERTY_KEY, "Invalid state."),
                        "Failed to process metadata.", new SsoProcessException("Invalid state.")));
    }

    /**
     * Gets the logout response.
     * @return The logout response.
     */
    protected ActionResponse getLogoutResponse() {

         * @throws ErrorResponseException If the server returns an error
         * @throws IllegalArgumentException If the arguments are invalid
         * @throws InsufficientDataException If insufficient data is available
         * @throws InternalException If an internal error occurs
         * @throws InvalidResponseException If the response is invalid

			if err != nil {
				return ep, fmt.Errorf("invalid URL endpoint format: invalid port number")
			} else if p < 1 || p > 65535 {
				return ep, fmt.Errorf("invalid URL endpoint format: port number must be between 1 to 65535")
			}
		}
		if i := strings.Index(host, "%"); i > -1 {
			host = host[:i]
		}

		if host == "" {
			return ep, fmt.Errorf("invalid URL endpoint format: empty host name")
		}

    }

    @DisplayName("Should throw exception for invalid structure size")
    @ParameterizedTest
    @ValueSource(ints = { 0, 1, 2, 4, 8, 15, 17, 32, 64, 65535 })
    void testReadBytesWireFormatInvalidStructureSize(int structureSize) {
        // Given
        byte[] buffer = new byte[256];
        int offset = 0;

        // Write invalid structure size
        SMBUtil.writeInt2(structureSize, buffer, offset);

        verify(smbFileHandle, times(1)).isValid();
    }

    /**
     * Test isValid() when the handle is invalid.
     */
    @Test
    void testIsValid_whenInvalid() {
        when(smbFileHandle.isValid()).thenReturn(false);
        assertFalse(smbFileHandle.isValid(), "isValid should return false when the handle is invalid.");
        verify(smbFileHandle, times(1)).isValid();
    }

    /**
     * Test close(long) successfully.

                    break;
                default:
                    throw new SmbException("Invalid operation for " + svc + " service: " + request);
                }
                break;
            default:
                throw new SmbException("Invalid operation for " + svc + " service" + request);
            }
        }
    }

    @SuppressWarnings("unchecked")

{* ../../docs_src/response_model/tutorial003_03.py hl[8:9] *}

This will also work because `RedirectResponse` is a subclass of `Response`, and FastAPI will automatically handle this simple case.

### Invalid Return Type Annotations { #invalid-return-type-annotations }

    if (hostname.isNullOrEmpty() ||
      hostname.startsWith(".") ||
      hostname.endsWith("..")
    ) {
      // Invalid domain name.
      return false
    }
    if (pattern.isNullOrEmpty() ||
      pattern.startsWith(".") ||
      pattern.endsWith("..")
    ) {
      // Invalid pattern.
      return false
    }

    }

    public void test_multipleNestedExceptions() {
        // Test with multiple nested exceptions
        Exception innerCause = new IllegalArgumentException("Invalid image format");
        Exception middleCause = new RuntimeException("Processing failed", innerCause);
        ThumbnailGenerationException exception = new ThumbnailGenerationException("Thumbnail generation error", middleCause);