By default, what the method `.openapi()` does is check the property `.openapi_schema` to see if it has contents and return them.

If it doesn't, it generates them using the utility function at `fastapi.openapi.utils.get_openapi`.

And that function `get_openapi()` receives as parameters:

* `title`: The OpenAPI title, shown in the docs.
* `version`: The version of your API, e.g. `2.5.0`.

 * governing permissions and limitations under the License.
 */
package org.codelibs.fess.crawler.util;

/**
 * Utility class for character-related operations.
 */
public final class CharUtil {
    /**
     * Private constructor to prevent instantiation of this utility class.
     */
    private CharUtil() {
    }

    /**
     * Checks if the given character is a valid URL character.
     *

import org.codelibs.fess.crawler.entity.ResponseData;
import org.codelibs.fess.crawler.exception.CrawlingAccessException;

/**
 * Utility class for handling response data.
 */
public final class ResponseDataUtil {

    /**
     * Private constructor to prevent instantiation of this utility class.
     */
    private ResponseDataUtil() {
    }

    /**

import org.codelibs.fess.Constants;

/**
 * Utility class for generating and writing thread dumps.
 * Provides methods to capture thread information for debugging purposes.
 */
public class ThreadDumpUtil {
    private static final Logger logger = LogManager.getLogger(ThreadDumpUtil.class);

    /**
     * Private constructor to prevent instantiation of this utility class.
     */
    protected ThreadDumpUtil() {

        validationMessagesLambda.message(messages);
        sessionManager.errors().saveMessages(messages);
    }

    /**
     * Copies properties from source bean to destination bean.
     * This is a utility method that wraps BeanUtil.copyBeanToBean with custom options.
     *
     * @param src the source bean object
     * @param dest the destination bean object
     * @param option a consumer function to configure copy options

import static org.mockito.Mockito.doAnswer;
import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.when;

/**
 * Utility class for creating test fixtures and reducing code duplication in tests.
 */
public final class TestUtils {

    private TestUtils() {
        // Utility class
    }

    /**
     * Creates a mock UpgradeContext with default settings.
     *
     * @return a mock UpgradeContext

import static eu.maveniverse.domtrip.maven.MavenPomElements.Elements.PLUGIN;
import static eu.maveniverse.domtrip.maven.MavenPomElements.Elements.VERSION;

/**
 * Utility class for XML operations on Maven POM files.
 *
 * <p>This class provides convenience methods that delegate to:
 * <ul>
 * <li>{@link eu.maveniverse.domtrip.maven.PomEditor} - DomTrip's PomEditor</li>

 */
package org.codelibs.core.misc;

import java.util.Base64;

import org.codelibs.core.collection.ArrayUtil;
import org.codelibs.core.lang.StringUtil;

/**
 * Utility class for handling Base64 encoding and decoding.
 * <p>
 * This class now uses the standard {@link java.util.Base64} implementation
 * instead of a custom implementation, providing better security and performance.

/**
 * Utility class for handling Maven model version operations during upgrades.
 *
 * <p>This class uses domtrip internally for superior formatting preservation
 * and simplified API while maintaining the same external interface.
 */
public final class ModelVersionUtils {

    private ModelVersionUtils() {
        // Utility class
    }

    /**

These examples are intentionally simple, but show how it all works.

In the chapters about security, there are utility functions that are implemented in this same way.

If you understood all this, you already know how those utility tools for security work underneath.

///