code: @Override
      public String keyDefault(String keyName, String defaultValue) {
  
          if (hasConfigValue(keyName)) {
              return getConfigValue(keyName);
          }
          return m_messages.keyDefault(keyName, defaultValue);
      }
docs: Returns the localized resource String from the configuration file, if not found or set from the resource bundle.<p>
  
  @see org.opencms.i18n.CmsMessages#keyDefault(java.lang.String, java.lang.String)