code: private void writeObject(ObjectOutputStream out) throws IOException {
          out.defaultWriteObject();
          out.writeInt(severity.getOrdinal());
          out.writeObject(summary);
          out.writeObject(detail);
          out.writeObject(rendered);
      }
docs: <p>Persist {@link javax.faces.application.FacesMessage} artifacts,
  including the non serializable <code>Severity</code>.</p>