Java EE javax.xml.bind.MarshalException

I am getting javax.xml.bind.MarshalException error. I am sending List from my webservice to the backingbean and I have this error.

WARNING: invocation error on ejb endpoint Login_webservice at /Login_webserviceService/Login_webservice : javax.xml.bind.MarshalException
 - with linked exception:
[javax.xml.bind.JAXBException: class JPA.Cantable nor any of its super class is known to this context.]
javax.xml.ws.WebServiceException: javax.xml.bind.MarshalException
 - with linked exception:
[javax.xml.bind.JAXBException: class JPA.Cantable nor any of its super class is known to this context.]
        at com.sun.xml.ws.message.jaxb.JAXBMessage.writePayloadTo(JAXBMessage.java:325)
        at com.sun.xml.ws.message.AbstractMessageImpl.writeTo(AbstractMessageImpl.java:142)
        at com.sun.xml.ws.encoding.StreamSOAPCodec.encode(StreamSOAPCodec.java:109)
        at com.sun.xml.ws.encoding.SOAPBindingCodec.encode(SOAPBindingCodec.java:278)
        at com.sun.xml.ws.transport.http.HttpAdapter.encodePacket(HttpAdapter.java:380)
        at com.sun.xml.ws.transport.http.HttpAdapter.access$100(HttpAdapter.java:92)
        at com.sun.xml.ws.transport.http.HttpAdapter$HttpToolkit.handle(HttpAdapter.java:525)
        at com.sun.xml.ws.transport.http.HttpAdapter.handle(HttpAdapter.java:285)
        at com.sun.xml.ws.transport.http.servlet.ServletAdapter.handle(ServletAdapter.java:143)
        at org.glassfish.webserv开发者_如何转开发ices.Ejb3MessageDispatcher.handlePost(Ejb3MessageDispatcher.java:116)
        at org.glassfish.webservices.Ejb3MessageDispatcher.invoke(Ejb3MessageDispatcher.java:87)
        at org.glassfish.webservices.EjbWebServiceServlet.dispatchToEjbEndpoint(EjbWebServiceServlet.java:196)
        at org.glassfish.webservices.EjbWebServiceServlet.service(EjbWebServiceServlet.java:127)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:847)

Here is my code:

Backing bean

@WebServiceRef(wsdlLocation = "http://localhost:26565/Login_webserviceService/Login_webservice?WSDL")
public String login() {
    System.out.println("Login Phase entered");
    int result = 0;
    List list;
    List finalList = null;
    try {
        Weblogin.LoginWebserviceService service = new Weblogin.LoginWebserviceService();
        Weblogin.LoginWebservice port = service.getLoginWebservicePort();
        result = port.login(voterID, password);
        Weblogin.LoginWebservice port1 = service.getLoginWebservicePort();
        list = port1.candDetails(1);
        finalList = list;
        this.setList(finalList);
    } catch (Exception e) {
        e.printStackTrace();
    }
    if (result == 1)
        return "polling";
    else
        return "login";
}

Webservice

public List candDetails(int pollEvent) {
    List resultList = null;
    List finalList = null;
    try {
        if (pollEvent == 1) {
            resultList = em.createNamedQuery("Cantable.findAll").getResultList();
            finalList = resultList;
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
    return resultList;
}

I think that the issue is somehow related to the JAX-WS and type substitution problem (there are plenty of thread about this problem on the java.net forums e.g. this one or this one). In a nutshell, JAXB is not able to marshal classes that are not referenced explicitly when the JAXBContext is created, which is the case for Cantable here.

I'm not 100% sure this will solve the problem but could you try to use a parametrized List instead of a raw type in your webservice:

public List<Cantable> candDetails(int pollEvent) {
   ...
}

Following up on Pascal's response, for a similar issue on the web service side, the parameterized list did not solve the problem but the @XmlSeeAlso annotation did.

@XmlSeeAlso({Cantable.class,Zot.class})
@WebService()
@Stateless()
public class Login {

Thanks Pascal!