JAXB creates empty TreeSet after unmarshaling

I have a RESTful service client. The service returns SortedSet<Movie>, where Movie is a JAXB annotated class. The resulting XML is given below.

On the client side, I have a custom MessageBodyReader as given below. The issue is that the Unmarshaller always returns an empty TreeSet.

MovieSetMessageBodyReader.java:

@SuppressWarnings("unchecked")
@Override
public TreeSet<Movie> readFrom(Class<TreeSet<Movie>> type,
    Type genericType, Annotation[] annotations, MediaType mediaType,
    MultivaluedMap<String, String> httpHeaders, InputStream entityStream)
    throws IOException, WebApplicationException {
Class<Movie> baseType = Types.getCollectionBaseType(type, genericType);

try {
    JAXBContext ctx = JAXBContext.newInstance(type, baseType);
    JAXBElement<?> element = ctx.createUnmarshaller().unmarshal(
        new StreamSource(entityStream), type);

    return (TreeSet<Movie>) element.getValue();
} catch (JAXBException e) {
    e.printStackTrace();
}

return null;
}

Mo开发者_如何学编程vieServiceRestEasyClient.java:

@GET
@Consumes("text/xml")
public SortedSet<Movie> sendRequestByProxy() {
Map<String, Object> requestAttributes = new HashMap<String, Object>();
requestAttributes.put("path", path);

MovieServiceRestEasy proxy = ProxyFactory.create(
    MovieServiceRestEasy.class, ENDPOINT, requestAttributes);
ClientResponse<TreeSet<Movie>> response = (ClientResponse<TreeSet<Movie>>) proxy
    .getMovieSet(path);
return response.getEntity(TreeSet.class, (new GenericType<TreeSet<Movie>>() {}).getGenericType());

}

XML:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<collection>
<movie>     
    <genre>Unknown</genre>
    <name>4.3.2.1</name>
    <year>2010</year>
</movie>
<movie>     
    <genre>Unknown</genre>
    <name>Battlestar Galactica The Plan</name>
    <year>2009</year>
</movie>
</collection>

Why don't you use POJO for holding the unmarshalled / marshalled values ? for example:

import javax.xml.bind.annotation.XmlAttribute;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;


@XmlRootElement( name = "movie" )
public class Movie
{
    @XmlElement
    String name;

    @XmlElement
    String genre;