FAQ
1. ERROR MESSAGE : Could not perform validation checks for component as the class was not found
- Turns out that if you are going to use a component as a composite key, the component must 
- Override equals 
- Override hashCode 
- Implement java.io.Serializable 
1. ERROR MESSAGE : ORA-00904: "ROLEELEMEN0_"."ID": invalid identifier
- The HQL was delete from RoleElement where role.id = :roleId 
- Bulk UPDATE/DELETE cannot include alias 
- Bulk UPDATE/DELETE cannot include join either explicit or implicit. - above HQL use implicit join in role.id 
- you can use sub-queries in the where-clause.