ServiceRegistry.Filter filter)
ServiceRegistry.Filter filter, Object readerExtension)
  private static Iterator getReadersByFilter(Class type,                                             ServiceRegistry.Filter filter)  {    try      {        Iterator it = getRegistry().getServiceProviders(type, filter, true);        return new ImageReaderIterator(it);      }    catch (IllegalArgumentException e)      {        return Collections.EMPTY_SET.iterator();      }  }