public void serializeUDFTable(OutputStream outputStream) throws IOException {
    List<UDFInformation> nonBuiltInUDFInformation = getAllInformationList();
    ReadWriteIOUtils.write(nonBuiltInUDFInformation.size(), outputStream);
    for (UDFInformation udfInformation : nonBuiltInUDFInformation) {
      ReadWriteIOUtils.write(udfInformation.serialize(), outputStream);
    }
  }
maintain a map for creating instance, model -> functionName -> class
iotdb-core/node-commons/src/main/java/org/apache/iotdb/commons/udf/UDFTable.java