// Verify that exception was handled
        assertTrue(exceptionHandled.get());
    }

    // Test with a custom ClassLoader to simulate class availability
    public void test_hook_withCustomClassLoader() throws Exception {
        // Create a custom ClassLoader that can control class loading behavior
        ClassLoader customClassLoader = new URLClassLoader(new URL[0], null) {
            @Override

Nevertheless, we can declare the expected schema for the request body.

### Custom OpenAPI content type { #custom-openapi-content-type }

Using this same trick, you could use a Pydantic model to define the JSON Schema that is then included in the custom OpenAPI schema section for the *path operation*.

And you could do this even if the data type in the request is not JSON.

        // Assert result is empty when successful
        assertEquals("", result);
    }

    public void test_execute_withCustomIndexName() {
        // Configure custom index name
        documentUpdateIndex = "custom.document.index";

        // Re-register FessConfig with updated index name
        fessConfig = new TestFessConfig() {
            @Override
            public String getIndexFieldExpires() {

        }
    }

    /**
     * Functional interface for building XContent with custom logic.
     * Allows clients to provide custom content building implementations.
     */
    public interface XContentBuilderCallback {
        /**
         * Applies custom logic to build XContent using the provided builder and parameters.
         *

 * provided by Maven and custom types registered through SPI provider implementations.
 *
 * @since 4.0.0
 */
@Experimental
public interface TypeRegistry extends ExtensibleEnumRegistry<Type> {

    /**
     * Obtain the {@link Type} from the specified {@code id}.
     * If no type is known for {@code id}, the registry will
     * create a custom {@code Type} for it.
     *

For example, let's add <a href="https://github.com/Rebilly/ReDoc/blob/master/docs/redoc-vendor-extensions.md#x-logo" class="external-link" target="_blank">ReDoc's OpenAPI extension to include a custom logo</a>.

### Normal **FastAPI** { #normal-fastapi }

First, write all your **FastAPI** application as normally:

{* ../../docs_src/extending_openapi/tutorial001.py hl[1,4,7:9] *}

   *
   * <p>Subclasses can override this method to provide custom equality.
   */
  @Override
  public boolean equals(@Nullable Object obj) {
    return super.equals(obj);
  }

  /**
   * By default delegates to {@link Object#hashCode}. The dynamic proxies' {@code hashCode()} will
   * delegate to this method. Subclasses can override this method to provide custom equality.
   */
  @Override
  public int hashCode() {

 * the symmetry of {@code equals}. Custom definitions of equality are usually based on an interface,
 * such as {@code Set} or {@code List}, so that the implementation of {@code equals} can cast the
 * object being tested for equality to the custom interface. {@code ForwardingObject} implements no
 * such custom interfaces directly; they are implemented only in subclasses. Therefore, forwarding

{* ../../docs_src/query_params_str_validations/tutorial014_an_py310.py hl[10] *}

## Custom Validation { #custom-validation }

There could be cases where you need to do some **custom validation** that can't be done with the parameters shown above.

In those cases, you can use a **custom validator function** that is applied after the normal validation (e.g. after validating that the value is a `str`).

	}
	fmt.Printf("%d\n", count)
	// Output: 15
}

// Use a Scanner with a custom split function (built by wrapping ScanWords) to validate
// 32-bit decimal input.
func ExampleScanner_custom() {
	// An artificial input source.
	const input = "1234 5678 1234567901234567890"
	scanner := bufio.NewScanner(strings.NewReader(input))
	// Create a custom split function by wrapping the existing ScanWords function.