[jboss-user] [Persistence, JBoss/CMP, Hibernate, Database] - Hibernate proxy class problem
georgesberscheid
do-not-reply at jboss.com
Thu Oct 11 16:51:54 EDT 2007
Hi,
I'm having the following odd situation:
| @Entity
| @Inheritance(strategy = InheritanceType.JOINED)
| public abstract class Customer { @Id private int id; }
|
| @Entity
| public class SomeCustomer extends Customer { private String name; }
|
I'm using Entity Manager to retrieve entities by their primary key:
| entityManager.find(Customer.class, 5);
|
The primary key 5 belongs to a SomeCustomer entity. It's in the id field of both Customer and SomeCustomer tables (due to join inheritance). However, the query returns an object that has the type Customer_$$_javassist_16 that cannot be cast to SomeCustomer (ClassCastException).
However, if I execute the following query:
| entityManager.find(SomeCustomer.class, 5);
|
I will see a warning in my logfile: ProxyWarnLog: Narrowing proxy to class SomeCustomer - this operation breaks ==
Subsequent call to the first find() query will now also return the right object of the right type.
Does anybody know what's going on here or how I can manually narrow down my proxy object to what I want to have if it fails?
Thanks a lot,
Georges
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