I am trying to call a User Defined Function in a Postgres database from Java through Hibernate. I am getting the error message "A CallableStatement was executed with an invalid number of parameters."

My Java code is

SessionFactory sessionFactory = configuration.buildSessionFactory();
Session session = sessionFactory.openSession();
Query query = session.getNamedQuery("validatecwmtest_F");
List<Object> res = query.list();

My Hibernate configuration of the query is

<sql-query name="validatecwmtest_F" callable="true">
<return class="com.stratix.esb.service.dao.hbm.CWMTest">
<return-property name="pkey" column="PKEY"/>
<return-property name="acctNum" column="ACCT_NUM"/>
</return>
{ ? = call validatecwmtest() }
</sql-query>

The validatecwmtest() user defined function was created with this SQL:

CREATE OR REPLACE FUNCTION validatecwmtest() RETURNS SETOF cwmtest AS $$
SELECT * FROM cwmtest;
$$ LANGUAGE SQL;

The table cwmtest was created with this SQL:

CREATE TABLE cwmtest
{
pkey serial NOT NULL PRIMARY KEY,
acct_num varchar(20) NULL
}

I would very much appreciate any help anyone can provide to resolve this error. Thanks!