assertNotNull(helper.duplicateHostList);
        assertEquals(1, helper.duplicateHostList.size());
        assertEquals("www.test.com", helper.duplicateHostList.get(0).getRegularName());
    }

    @Test
    public void test_add_withNullList() {
        DuplicateHostHelper helper = new DuplicateHostHelper();
        helper.duplicateHostList = null;

        LogNotificationHelper helper = new LogNotificationHelper();
        // destroy() without init() should not throw NPE because of null checks
        helper.destroy();
    }

    @Test
    public void test_init_destroy_multipleRounds() {
        LogNotificationHelper helper = new LogNotificationHelper();
        helper.init();
        helper.destroy();
        // Second round
        helper.init();

### Service
- Inject behaviors (Bhv) for data access
- Use `OptionalEntity<T>` for nullable returns
- Plain classes (no extends/implements)

### Helper
- Stateless utility classes
- Access via `ComponentUtil.getXyzHelper()`
- Named with "Helper" suffix

### DBFlute Generated Code
```
opensearch/{index}/
├── bsentity/, bsbhv/    # Base classes (DO NOT EDIT)

        } catch (final Exception e) {
            return;
        }

        final LogNotificationHelper helper;
        try {
            helper = ComponentUtil.getLogNotificationHelper();
        } catch (final Exception e) {
            return;
        }

        final List<LogNotificationEvent> events = helper.drainAll();
        if (events.isEmpty()) {
            return;
        }

        try {

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
 * either express or implied. See the License for the specific language
 * governing permissions and limitations under the License.
 */
package org.codelibs.fess.helper;

import java.io.File;
import java.io.FileInputStream;
import java.io.InputStream;

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.codelibs.core.lang.StringUtil;

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
 * either express or implied. See the License for the specific language
 * governing permissions and limitations under the License.
 */
package org.codelibs.fess.helper;

import java.util.LinkedHashMap;
import java.util.Map;

import org.apache.commons.lang3.StringUtils;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;

    /**
     * Default constructor for DuplicateHostHelper.
     * Creates a new duplicate host helper instance.
     */
    public DuplicateHostHelper() {
        // Default constructor
    }

    /**
     * Initializes the duplicate host helper after construction.
     * Loads duplicate host configurations from the DuplicateHostService.
     */
    @PostConstruct

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
 * either express or implied. See the License for the specific language
 * governing permissions and limitations under the License.
 */
package org.codelibs.fess.helper;

import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Locale;
import java.util.Map;

import org.apache.logging.log4j.LogManager;

import org.apache.logging.log4j.core.config.plugins.PluginElement;
import org.apache.logging.log4j.core.config.plugins.PluginFactory;
import org.codelibs.fess.helper.LogNotificationHelper;
import org.codelibs.fess.helper.LogNotificationHelper.LogNotificationEvent;

/**
 * Custom Log4j2 Appender that captures log events into a buffer for notification purposes.
 */

        return relatedContentBhv.selectByPK(id);
    }

    /**
     * Stores (inserts or updates) a related content entity.
     * After storing, updates the related content helper to refresh the cache.
     *
     * @param relatedContent the RelatedContent entity to store
     */
    public void store(final RelatedContent relatedContent) {