Question

I’m using eclipselink-2.3.2. My package is annotated:

@XmlSchema(namespace = "http://example.com/namespace", elementFormDefault = XmlNsForm.QUALIFIED)

I have the following classes:

@XmlRootElement
public class Box {
    private A item; // and getter/setter
}

@XmlDiscriminatorNode("@thetype")
public abstract class A {}

@XmlDiscriminatorValue("b")
public class B extends A {}

@XmlDiscriminatorValue("c")
public class C extends A {}

When I try to deserialize valid XML like this:

<box xmlns="http://example.com/namespace"><a thetype="b" /></box>

I get the descriptive exception:

org.eclipse.persistence.exceptions.DescriptorException
Exception Description: Missing class indicator field from database row [UnmarshalRecord()]

If I remove the @XmlSchema from the package and the xmlns attribute from the root element, it works. If I change from QUALIFIED to UNQUALIFIED, it works as long as I feed it the ugly prefixed XML.

I assumed that the unprefixed would work since it still declares the default namespace, but although there is no exception the field remains null.

After stepping through the EclipseLink code, I can see that when QNameInheritancePolicy.classFromRow calls UnmarshalRecord.get, it is trying to access the attribute “thetype” under the namespaceURI “http://example.com/namespace”.

When I change the XmlScehma elementFormDefault to UNQUALIFIED, the namespaceURI comes back null and the attribute is properly retrieved.

Answer 1

This is a bug in EclipseLink JAXB (MOXy). You can track our progress on this issue using the link below. I already have a fix attached to the bug, I’ll check it in once the test cases have finished running.

• http://bugs.eclipse.org/377967

UPDATE

This bug has now been fixed. You can try it out by obtaining one of the EclipseLink 2.4.0 nightly builds starting April 30th, 2012:

• http://www.eclipse.org/eclipselink/downloads/nightly.php