Of course it was something simple. After ripping apart my project until it was just one set of bare bones jars and classes and still seeing the error, I restored from cvs, cursed the computer and made some coffee. After a few sips away from the computer, I realized what happened. A quick trip to my desk, followed by one tap (ok, slam) of the delete key confirmed it.
This part was correct as we thought it should be: <result property="categories" column="{testId=test_id, asmtId=assessment_id}" select="getCompetencyTypes" /> But, the corresponding select statement looked like this: <select id="getCompetencyTypes" parameterClass="int" resultMap="competencyTypeResult"> Removing parameterClass="int" made the problem go away. Cheers, - stuart