JAXB does not marshall as expected. An object(superclass) whitin a DTO is empty

Question

After hours of try and error I want ask here if someone could help me to solve my problem.

Scenario:

• Java EE Server (JBoss 7.2) with Apache CXF as JAX-WS implementation.
• ServiceA (Service Endpoint) and ServiceB (extends Service A and also Service Endpoint)
• Three Persistence Projects: Common, PersistenceA depends Common, PersistenceB depends PersistenceA.
• There is a Class UUIDIdentified that is Superclass of all persistence Classes (It provides the JPA @ID) it is in Projekt Common

Within the ServiceA Class is an Method: public List<DTO> getData(UUIDIdentified value);

The Server reads some Objects that are all subtypes of UUIDIdentified, and the goal is to pack the Objects in DTOs.

A DTO would look like:

@XmlAccessorType(XmlAccessType.FIELD)
public class DTO{

private static final long serialVersionUID = 1L;

@XmlElement(name = "uuididentified")
UUIDIdentified object;

public UUIDIdentified getObject() {
    return object;
}

public void setObject(final UUIDIdentified object) {
    this.object = object;
}
}

If i look into the SOAP response, I see that there is no Data in the <uuididentified> tag. My understanding of JAXB isnt so well, but as I understand the "real" instances of the UUIDIdentified and their types are unknown to the JAXBContext.

I could solve this by adding @XmlSeeAlso({TypeA.class,TypeB.class}) to the UUIDIdentified class (I reckon). But that is what I cant because if i would do so, the Project Common would depend on Projects PersistenceA/B.

How can I solve this. How can I say to JAXB(Maybe in a xml config file) that it have to add ClassA/B to the JAXBContext as it adds UUIDIdentified?

I tried some things like jaxb.index files, ObjectFactorys, @XmlSeeAlso on the SEI but I dont know if that is the right way.

Answer 1

After I tried to marshall/unmarshal the object by my self, with @XmlJavaTypeAdapter i faced the root of the problem. It wasn't anything with the JAXBContect. The Problem was my Object was a Hibernate-Envers read object, and envers produces Proxy Objects(even if they are EAGER).

So the marshaller could not extract the real value from the Proxy object.