private void restore() {
    try {
      importCookies(persister.restore());
    } catch (PersistenceException e) {

      if (logErrors) {
        e.printStackTrace();
      }

      exceptionHandler.onRestoreFailure(e);
    }
  }
  private void persist() {
    try {
      persister.persist(exportCookies());
    } catch (PersistenceException e) {

      if (logErrors) {
        e.printStackTrace();
      }

      exceptionHandler.onPersistFailure(new PersistenceException(e));
    }
  }