public static List<String> getColumnNames(List<FieldSchema> cols) {
    if (CollectionUtils.isNotEmpty(cols)) {
      return cols.stream().map(FieldSchema::getName).map(String::toLowerCase).collect(Collectors.toList());
    }
    return null;
  }
Generate list of lower case column names from the fieldSchema list
@param cols fieldSchema list
@return column name list
standalone-metastore/metastore-server/src/main/java/org/apache/hadoop/hive/metastore/utils/MetaStoreServerUtils.java