Hibernate returns list of nulls although executed SQL returns values

Question

I'm using hibernate as an ORMapper. I want to execute an actually rather simple hql query:

SELECT a 
FROM Foo a 
WHERE a.status = :A0status 
ORDER BY a.bookingTypeCode ASC, 
         a.priority ASC

This hql query is then converted into a sql query which looks something like this:

select a.* 
from Foo a 
where a.status='A' 
order by a.bookingtypecode ASC, 
         a.priority ASC

When I execute the sql on the oracle database using the Oracle SQL Developer I get 17 rows returned. However, when I execute the hql query (using the list method of a Query I get a list of 17 elements that are all null. Although the number of elements is correct, not a single one of the elements is actually loaded.

This is the way I create and execute my query:

// the hql query is stored in the hqlQuery variable;
// the parameter are stored in a Map<String, Object> called params
Query hQuery = hibSession.createQuery(hqlQuery);
for (Entry<String, Object> param : params.entrySet()) {
    String key = param.getKey();
    Object value = param.getValue();
    hQuery.setParameter(key, value);
}

List<?> result = hQuery.list();

Does anyone know what might be the problem here?

Update 1

I've recently upgrade from hibernate 3.2 to 4.3.5. Before the upgrade everything worked fine. After the upgrade I get this error.

Solution 1

I've set the Log level of hibernate to TRACE and found the problem. It was actually a mapping/logic/database error. The primary key consisted of two columns (according to the entity class) and one of these columns was nullable. However a primary key can never be nullable. Therefore hibernate always returned null.

Solution 2

If you have not set a custom (and buggy) ResultTransformer, my second best guess is that your debugger is lying to you. Does you code actually receives a list of null?

Also make sure to test with the code you are showing is. Too many times, people simplify things and the devil is in the details.

Comments

[mvieghofer]

Hi, no I did not set acustom ResultTransformer and the list returned is actually a list of nulls (I'm getting a NullPointerException because of this). Also the SQL I've posted above is more or less exactly the SQL that is generated by hibernate (I just simplified it by selecting * and changing the alias).

[Jeremy]

Worked for me, I had switched the column by which I needed to annotate with @Id in my domain class that hibernate was mapping DB objects into. In my case my table did not have a primary key, but the annotation still caused the nulls because hibernate doesn't want a null ID even in the instances it creates from the DB query results regardless if its a primary key or not.

[banan3'14]

I had to set the log level to FINEST, it was a problem with the query in my case. For anyone wondering how to set the log level stackoverflow.com/a/847121/7769052