Getting a bad SQL grammar error for a named parameter - removing the parameter eliminates the error

Question

I have looked one by one at all of the other questions, and I am not overcoming my issue. I have vastly simplified the code, and I have what I believe is a novel demonstration of the issue.

This code works:

@Repository
public class MyFriend {
    @Autowired  
    private NamedParameterJdbcTemplate namedParameterJdbcTemplate;
    public List<TransmitUnit> getTransmissionList(LocalDate workingDate)
    {
        List<TransmitUnit> retValue = null;     
        String sql = "SELECT working_day as workingDate, origin_code as originCode FROM core.sort_transmission WHERE working_day = '2024-08-23'";
        MapSqlParameterSource namedParameters = new MapSqlParameterSource();
        namedParameters.addValue("working_day", workingDate.toString());
        retValue = namedParameterJdbcTemplate.query(sql, namedParameters, new BeanPropertyRowMapper<>(TransmitUnit.class));
        for (TransmitUnit u: retValue) {
            LOGGER.info("Got this tu {}", u.getWorkingDate());
        }
        return retValue;
    }

If I replace the '2024-08-23' in sql with a named parameter:

String sql = "SELECT working_day as workingDate, origin_code as originCode 
FROM core.sort_transmission WHERE working_day = :working_day";

Now, I get an error in the statement:

ERRO class="MyFriend" method="getTransmissionList" transactionId="6913d8d6-d56a-4c8f-bd78-32c976817d39-1724878713995" 
request="[2024-08-28]" errorType="org.springframework.jdbc.BadSqlGrammarException" errorMsg="PreparedStatementCallback; bad SQL grammar 
[SELECT working_day as workingDate, origin_code as originCode 
FROM core.sort_transmission WHERE working_day = ?]" errorOrigin="org.springframework.jdbc.support.SQLStateSQLExceptionTranslator.doTranslate(SQLStateSQLExceptionTranslator.java:104)"

I am wondering why the SQL shows a ? as if this was a generic prepared statement instead of with a named parameter. I know this has worked before, I am not sure what I could be doing wrong.

EDIT: Based on John Bollinger's comment I submitted an answer that I think nicely illustrates the exact type problem and would be enlightening for future viewers.

Answer 1

John Bollinger was correct. The type in Java needs to match the type in SQL. Removing the toString() worked.

Final working code:

@Repository
public class MyFriend {
    @Autowired  
    private NamedParameterJdbcTemplate namedParameterJdbcTemplate;
    public List<TransmitUnit> getTransmissionList(LocalDate workingDate)
    {
        List<TransmitUnit> retValue = null;     
        String sql = "SELECT working_day as workingDate, origin_code as originCode FROM core.sort_transmission WHERE working_day = :working_day";
        MapSqlParameterSource namedParameters = new MapSqlParameterSource();
        namedParameters.addValue("working_day", workingDate);
        retValue = namedParameterJdbcTemplate.query(sql, namedParameters, new BeanPropertyRowMapper<>(TransmitUnit.class));
        for (TransmitUnit u: retValue) {
            LOGGER.info("Got this tu {}", u.getWorkingDate());
        }
        return retValue;
    }