First, I would recommend that you take the error's advice and set hibernate.cglib.use_reflection_optimizer=false so that you can see what the actual error is. Most likely the problem is that you have a not-null="false" field (since the database supports null on the column) mapped to a primitive boolean. If this is the case, you really only have two good options.
- Switch your Java type to a java.lang.Boolean
- or set all the null fields in the database to be false (which is what you are suggesting is your default) and set the database field to default to false with a not null restriction.