private RowDataToFieldConverter wrapIntoNullableConverter(RowDataToFieldConverter converter) {
        return inputObj -> {
            if (inputObj == null) {
                return null;
            }

            return converter.convert(inputObj);
        };
    }
Creates a runtime converter which assuming input object is not null.
inlong-sort/sort-formats/format-rowdata/format-rowdata-json/src/main/java/org/apache/inlong/sort/formats/json/RowDataToFieldConverters.java