ClassCastException while Unmarshalling XML with JAXB

Question

I have generated java classes using xjc from an xsd where the root element was A of type AType.

The root element generated by jaxb is AType & no class A has been generated.

When I try to unmarshall an xml corresponding to that xsd and cast the JaxbElement it is throwing a cast exception:

Snippet:

JAXBContext jaxbContext = JAXBContext.newInstance(Class.forName("AType"));
Unmarshaller unmarshaller = jaxbContext.createUnmarshaller();
AType aType = (AType) unmarshaller.unmarshal(new ByteArrayInputStream(xmlString.getBytes()));

Exception:

java.lang.ClassCastException: javax.xml.bind.JAXBElement

Same code for other cases execute properly and successfully deserialize.

How can I find unmarshal() gives me object of what type? I have no clue what's going wrong in this situation, I've tried printing out fields in that jaxbElement but it was not very useful!

Answer 1

If the class of the root element (here: AType) doesn't contain the XmlRootElement-annotation, then the returned root element gets wrapped in a JAXBElement and you have to use its getValue()-method to get the root element.

AFAIK, XJC will only generate the XmlRootElement-annotation if the type of the root element is an anonymous type.