I've got the same problem describing in here:
But switching to a Blob attribute didn't help:
it is still loading BLOB column in a query!
I played with hibernate.bytecode.use_reflection_optimizer but got the same result.
Another idea was calling hibernate's javassist instrument task during building the application. It affected the exception during deploying:
javax.persistence.PersistenceException: org.hibernate.MappingException: Could no
t determine type for: org.hibernate.bytecode.javassist.FieldHandler, for columns