presto-hive/src/main/java/io/prestosql/plugin/hive/GenericHiveRecordCursor.java/GenericHiveRecordCursor/parseObjectColumn
class GenericHiveRecordCursor:    private void parseObjectColumn(int column)
    {
        loaded[column] = true;

        Object fieldData = rowInspector.getStructFieldData(rowData, structFields[column]);

        if (fieldData == null) {
            nulls[column] = true;
        }
        else {
            objects[column] = getBlockObject(types[column], fieldData, fieldInspectors[column]);
            nulls[column] = false;
        }
    }