### Code Standards
- Follow the project's Eclipse formatter configuration
- Add Apache License 2.0 headers to new files: `mvn license:format`
- Maintain comprehensive JavaDoc documentation
- Write thorough unit tests with good coverage
- Follow existing naming conventions and patterns

## 📄 License

import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicLong;

import org.codelibs.fess.entity.DataStoreParams;
import org.codelibs.fess.unit.UnitFessTestCase;

public class IndexUpdateCallbackTest extends UnitFessTestCase {

    public void test_interface_methods() {
        // Test with anonymous implementation

 */
package org.codelibs.fess.util;

import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;

import org.codelibs.fess.Constants;
import org.codelibs.fess.unit.UnitFessTestCase;

public class SystemUtilTest extends UnitFessTestCase {

    public void test_getSearchEngineHttpAddress_null() {
        // Clear the system property to test null case

import org.mockito.Mock;
import org.mockito.MockitoAnnotations;

import jcifs.Configuration;
import jcifs.internal.dtyp.SecurityDescriptor;
import jcifs.internal.util.SMBUtil;

/**
 * Unit tests for NtTransQuerySecurityDescResponse class
 */
class NtTransQuerySecurityDescResponseTest {

    @Mock
    private Configuration mockConfig;

    private NtTransQuerySecurityDescResponse response;

import java.time.LocalDateTime;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.codelibs.fess.unit.UnitFessTestCase;
import org.dbflute.optional.OptionalEntity;

public class OptionalUtilTest extends UnitFessTestCase {

    public void test_ofNullable_withNonNullString() {
        String testValue = "test string";

import org.codelibs.fess.opensearch.config.exentity.BoostDocumentRule;
import org.codelibs.fess.opensearch.config.exentity.FileConfig;
import org.codelibs.fess.opensearch.config.exentity.WebConfig;
import org.codelibs.fess.unit.UnitFessTestCase;
import org.codelibs.fess.util.ComponentUtil;

public class WebFsIndexHelperTest extends UnitFessTestCase {

    private WebFsIndexHelper webFsIndexHelper;

    @Override

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

import org.codelibs.fess.mylasta.direction.FessConfig;
import org.codelibs.fess.unit.UnitFessTestCase;
import org.codelibs.fess.util.ComponentUtil;

public class PermissionHelperTest extends UnitFessTestCase {

    public PermissionHelper permissionHelper;

    @Override

 * either express or implied. See the License for the specific language
 * governing permissions and limitations under the License.
 */
package org.codelibs.fess.entity;

import org.codelibs.fess.unit.UnitFessTestCase;

public class FessUserTest extends UnitFessTestCase {

    public void test_getName() {
        // Test with normal user name

import org.mockito.Mock;
import org.mockito.MockedStatic;
import org.mockito.Mockito;
import org.mockito.junit.jupiter.MockitoExtension;

import jcifs.pac.PACDecodingException;

/**
 * Unit tests for the KerberosTicket class.
 */
@ExtendWith(MockitoExtension.class)
class KerberosTicketTest {

    @Mock
    private KerberosKey kerberosKey;

    private KerberosKey[] keys;

import org.codelibs.fess.entity.GeoInfo;
import org.codelibs.fess.entity.HighlightInfo;
import org.codelibs.fess.entity.SearchRequestParams;
import org.codelibs.fess.mylasta.action.FessUserBean;
import org.codelibs.fess.unit.UnitFessTestCase;
import org.codelibs.fess.util.FacetResponse;
import org.opensearch.search.aggregations.Aggregations;
import org.opensearch.search.aggregations.InternalAggregations;
import org.dbflute.optional.OptionalThing;