* Adds a password validation error message to the messages object based on the error key.
     *
     * @param messages the FessMessages object to add the error to
     * @param errorKey the error key identifying the type of password validation error
     */
    protected void addPasswordValidationError(final FessMessages messages, final String errorKey) {
        switch (errorKey) {
        case "errors.password_length":

     * Adds a password validation error message to the messages object based on the error key.
     *
     * @param messages the FessMessages object to add the error to
     * @param errorKey the error key identifying the type of password validation error
     */
    protected void addPasswordValidationError(final FessMessages messages, final String errorKey) {
        switch (errorKey) {
        case "errors.password_length":

     * Adds a password validation error message to the messages object based on the error key.
     *
     * @param messages the FessMessages object to add the error to
     * @param errorKey the error key identifying the type of password validation error
     */
    protected void addPasswordValidationError(final FessMessages messages, final String errorKey) {
        switch (errorKey) {
        case "errors.password_length":

         * @return This ApiErrorResponse instance.
         */
        public ApiErrorResponse message(final VaMessenger<FessMessages> validationMessagesLambda) {
            final FessMessages messages = new FessMessages();
            validationMessagesLambda.message(messages);
            message = ComponentUtil.getMessageManager()

manage.bat     # On Windows
# Select option 23 (generate)
```

This will regenerate:
- `src/main/java/org/codelibs/fess/mylasta/action/FessLabels.java`
- `src/main/java/org/codelibs/fess/mylasta/action/FessMessages.java`
- `src/main/java/org/codelibs/fess/mylasta/direction/FessProp.java`

### 5. Rebuild the Project

```bash
mvn clean package
```

### 6. Test the New Language

1. **Start Fess:**

import org.codelibs.fess.app.service.GroupService;
import org.codelibs.fess.app.web.CrudMode;
import org.codelibs.fess.app.web.base.FessAdminAction;
import org.codelibs.fess.mylasta.action.FessMessages;
import org.codelibs.fess.opensearch.user.exentity.Group;
import org.codelibs.fess.util.ComponentUtil;
import org.codelibs.fess.util.RenderDataUtil;
import org.dbflute.optional.OptionalEntity;

import org.codelibs.fess.helper.QueryHelper;
import org.codelibs.fess.helper.SearchHelper;
import org.codelibs.fess.helper.SystemHelper;
import org.codelibs.fess.mylasta.action.FessMessages;
import org.codelibs.fess.mylasta.direction.FessConfig;
import org.codelibs.fess.opensearch.client.SearchEngineClient;
import org.codelibs.fess.util.ComponentUtil;
import org.codelibs.fess.util.RenderDataUtil;

     * @param runtimeGroups   The runtime groups.
     * @return A new action validator.
     */
    public ActionValidator<FessMessages> createValidator(final RequestManager requestManager,
            final UserMessagesCreator<FessMessages> messagesCreator, final Class<?>[] runtimeGroups) {
        return new FessActionValidator<>(requestManager, messagesCreator, runtimeGroups);
    }

    /**