Hi

I have a parent/child relationship (tables P and C). My Java classes are PImpl.java and CImpl.java. Two interfaces, P.java and C.java, are implemented by parent and child respectively, i.e.,

public class CImpl implements C { ... }
public class PImpl implements P { ... }

Currently, I define C.getP() to return P the interface, i.e.,

public P getP() { return this.p; }

However, it seems that for C to return P, P must have its own mapping file. At runtime, I'm getting an exception saying that P is an interface or abstract class and cannot be instantiated. On the other hand, if getP() is to return the concrete P, the method signature has to be:

public PImpl getP()

which is not what I want. So, my question is, how do I do this properly?

I've attached the runtime exception I've got when Hibernate tried to instantiate the interface. Thanks.

cirrus.hibernate.HibernateException: Cannot instantiate abstract class or interface: P
at cirrus.hibernate.persister.AbstractEntityPersister.instantiate(AbstractEntityPersister.java:301)
at cirrus.hibernate.loader.Loader.getRow(Loader.java:301)
at cirrus.hibernate.loader.Loader.doFind(Loader.java:160)
at cirrus.hibernate.loader.Loader.loadEntity(Loader.java:503)

All this information is completely useless w/o a mapping file.

Hi Steve

It works now. The problem arose because I also have a one-to-many relationship from parent to child. I incorrectly put the interface name of the child in the <set> element. Once I've resolved to use the concrete class names it works just fine now.

Thanks a lot!