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I am currently trying to unmarshal an XML document via JAXB. I've already have generated the JAXB classes within my project, and have a root class annotated with @XmlRootElement.

Unfortunately, when I attempt to unmarshal, I receive the following exception:

java.lang.ClassCastException: javax.xml.bind.JAXBElement cannot be cast to a.b.Foo

My Foo class has the proper annotation, and as far as I'm aware, this should be able to unmarshal my XML into the Foo class.

Any thoughts on what could cause this?

Edit (for clarification): The call I'm attempting to make to unmarshal is this:

Foo foo = (Foo)unmarshaller.unmarshal(input);

Second Update I'm not allowed to update our schema, but below is the XML schema structure to the 'Foo' element...

<xsd:element name="Foo" type="Foo_Type"/>
<xsd:complexType name="Foo_Type">
    <!-- more schema definition here -->
</xsd:complexType>

I am then adding the @XmlRootElement annotatino to the Foo class via JAXB Bindings. I've found that if I change the schema to be like so:

<xsd:element name="Foo">
    <xsd:complexType>
        <!-- more schema definition here -->
    </xsd:complexType>
</xsd:element>

Everything works fine, but once again -- we're not supposed to be updating the schema.

Patrick
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1 Answers1

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A class with an @XmlRootElement annotation should only be unmarshalled to an instance of JAXBElement if one of the unmarshal methods that takes a Class parameter is used.

UPDATE

If your unmarshal code is the following:

Foo foo = (Foo)unmarshaller.unmarshal(input);

Then you must have an @XmlElementDecl on a class annotated with @XmlRegistry (by default this class is called ObjectFactory when the model is generated from an XML Schema) corresponding to the Foo class. I have written more about this on my blog:

bdoughan
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  • I've updated the original post to clarify how I'm making the call to the unmarshaller. I am not passing a Class parameter, only the XML input. What else could cause a JAXBElement to be returned? – Patrick Jun 05 '15 at 22:21
  • Thanks for the update. I've looked into my ObjectFactory class and indeed saw that there is an @XmlElementDecl annotation on the method for the createFoo() class. But, there is also just a POJO createFoo() method as well. Is there a way to prevent the JAXB Class generation from creating the createFoo() that returns the JAXBElement object? – Patrick Jun 08 '15 at 14:59