code: private void setupExceptionPropagator() {
      if (cache2kConfiguration.getExceptionPropagator() != null) {
        return;
      }
      cache2kConfiguration.setExceptionPropagator(
        new CustomizationReferenceSupplier<ExceptionPropagator<K>>(new ExceptionPropagator<K>() {
        @Override
        public RuntimeException propagateException(Object key, final ExceptionInformation exceptionInformation) {
          return new CacheLoaderException("propagate previous loader exception", exceptionInformation.getException());
        }
      }));
    }
docs: If an exception propagator is configured, take this one, otherwise go with default that
  is providing JCache compatible behavior.