Trouble with "return null" in Resource Method

[Christian Bitschnau]

Hi,

I'm using Apache Wink 1.1 in a Websphere Environment and an exception  
from the following client code:

// Server:
@Path("/jobs")
@Consumes(value = MediaType.TEXT_XML)
@Produces(value = MediaType.TEXT_XML)
public class ConfigJobs {

	private static final Logger LOG =  
Logger.getLogger(ConfigJobs.class.getName());

        private WasAdminWSService service;

        public ConfigJobs() {
                //...
        }

        @GET
        @Path(value = "forCell/{cell}")
        @Produces({ MediaType.TEXT_XML })
	public Job getNextConfigJob(@PathParam(value = "cell") String cell)  
throws DatatypeConfigurationException {
                // service may return null
                return service.getNextJob(new CellName(cell));
        }
}


// Client:
public ConfigJob getConfigJob() {
        String relPath = "jobs/forCell/" + config.getCellName();
        Resource resource = webResourceFactory.createNewInstance(relPath);

//next line results in Exception
	ConfigJob configJob =  
resource.accept(MediaType.TEXT_XML).get(ConfigJob.class);

        if (configJob != null && configJob.getCellName() != null) {
                LOG.fine("found a job");
        }

        return configJob;
}



// Exception:

Mar 10, 2014 1:21:49 PM.700  INFO MessageDispatcher.getConfigJob():   
GET jobs/forCell/abc
java.lang.RuntimeException: A javax.ws.rs.ext.MessageBodyReader  
implementation was not found for class bla.wasadmin.wsdata.ConfigJob  
type and application/octet-stream media type.  Verify that all entity  
providers are correctly registered.  Add a custom  
javax.ws.rs.ext.MessageBodyReader provider to handle the type and  
media type if a JAX-RS entity provider does not currently exist.
        at  
org.apache.wink.client.internal.handlers.ClientResponseImpl.readEntity(ClientResponseImpl.java:134)
        at  
org.apache.wink.client.internal.handlers.ClientResponseImpl.getEntity(ClientResponseImpl.java:76)
        at  
org.apache.wink.client.internal.handlers.ClientResponseImpl.getEntity(ClientResponseImpl.java:63)
        at  
org.apache.wink.client.internal.ResourceImpl.invoke(ResourceImpl.java:196)
        at  
org.apache.wink.client.internal.ResourceImpl.get(ResourceImpl.java:302)
        at  
bla.wasadmin.impl.MessageDispatcher.getConfigJob(MessageDispatcher.java:36)
        at bla.wasadmin.jmx.job.JobRunnerTask.task(JobRunnerTask.java:55)
        at bla.wasadmin.jmx.job.JobRunnerTask.run(JobRunnerTask.java:91)
        at java.util.Timer$TimerImpl.run(Timer.java:296)

Actually, I'd expect to get null to the server instead of this Error.  
Is there a failure in my understanding of writing JAX-RS webservice  
with wink?

Is there a possibility to get null to the server?

Thank's for helping in advance,

Christian