public static List<FieldSchema> getColumns(ASTNode ast, boolean lowerCase, Configuration conf)
      throws SemanticException {
    return getColumns(ast, lowerCase, null, new ArrayList<>(), new ArrayList<>(), new ArrayList<>(),
            new ArrayList<>(), new ArrayList<>(), new ArrayList<>(), conf);
  }
Get the list of FieldSchema out of the ASTNode.
ql/src/java/org/apache/hadoop/hive/ql/parse/BaseSemanticAnalyzer.java