MultiUserChat.destroy() not-authoried(401)

Look at my codes:

              muc.create(roomName);

              Form form = muc.getConfigurationForm();

              Form submitForm = form.createAnswerForm();

              for (Iterator<FormField> fields = form.getFields(); fields

                                                  .hasNext();) {

                                        FormField field = (FormField) fields.next();

                                        if (!FormField.TYPE_HIDDEN.equals(field.getType())

                                                            && field.getVariable() != null) {

                         submitForm.setDefaultAnswer(field.getVariable());

                                        }

                              }

              List<String> owners = new ArrayList<String>();

                              owners.add(userJid);

                              submitForm.setAnswer("muc#roomconfig_roomowners", owners);

                              submitForm.setAnswer("muc#roomconfig_roomadmins", owners);

               submitForm.setAnswer("muc#roomconfig_persistentroom", true);

I create a room and set its onwers.then I login out.After a while,I login in.But I can get the owners of the room.

I don't known how to resolve it.