Re: [eclipselink-users] EntityManager.find returning instance of wrong t

[jsw <marvin.438@xxxxxxxxx>]

OK, thank you, it seems I had misunderstood how to use the @Inheritance
annotation. However, in this case it does not seem to make a difference
since SINGLE_TABLE is the default inheritance type.

Unfortunately, moving the @Inherintance annotation to the base class did not
solve my problem. EntityManager.find keeps trying to return an instance of
the wrong entity.

Maybe something more I've misunderstood?



tch wrote:
> 
> I've never used the @Inheritance annotation, but I believe it goes on
> the base class, not the extending entity.
> 
> See:
> http://www.oracle.com/technology/products/ias/toplink/jpa/howto/use-inheritance.html
> 
> 
> 
> On Fri, Mar 6, 2009 at 3:00 AM, jsw <marvin.438@xxxxxxxxx> wrote:
>>
>> Environment: JBoss, Jersey, Spring, EclipseLink JPA, PostgreSQL
>>
>> @Entity
>> public abstract class Base {
>>    @Id
>>    @GeneratedValue(strategy = GenerationType.TABLE)
>>    private Long id;
>>
>>    @Version
>>    private long version;
>>
>>    ...
>> }
>>
>> @Entity
>> @Inheritance(strategy=InheritanceType.SINGLE_TABLE)
>> public class Foo extends Base { ... }
>>
>> @Entity
>> @Inheritance(strategy=InheritanceType.SINGLE_TABLE)
>> public class Bar extends Base { ... }
>>
>> Then when I do:
>>
>>    Long aId = 76576; // a valid id for an entity of type Bar
>>    Foo foo = em.find(Foo.class, aId); // em is EntityManager
>>
>> an exception is thrown (the root cause seems to be ClassCastException)
>> because the EntityManager tries to return an object of type Bar.
>>
>> What am I doing wrong?
>> --
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>>
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