private List<MStringList> convertToMStringLists(List<List<String>> mLists) {
    List<MStringList> lists = null ;
    if (null != mLists) {
      lists = new ArrayList<>();
      for (List<String> mList : mLists) {
        lists.add(new MStringList(mList));
      }
    }
    return lists;
  }
Convert a list of MStringList to a list of list string
standalone-metastore/metastore-server/src/main/java/org/apache/hadoop/hive/metastore/ObjectStore.java