docs: private static String getDefaultPersistentFieldClassName()
      {
          try
          {
              PersistenceBrokerConfiguration config =
                      (PersistenceBrokerConfiguration) OjbConfigurator.getInstance().getConfigurationFor(
                              null);
  
              Class clazz = config.getPersistentFieldClass();
              return clazz.getName();
          }
          catch (ConfigurationException e)
          {
              log.error("Cannot look-up PersistentField class, use default implementation instead", e);
              return DEFAULT_PERSISTENT_FIELD_IMPL.getName();
          }
      }