Java Restful Service: Incorrect HTTP error for xml requests

Controller looks like this:

@GET
@Path("/entity/{entityId}")
@Produces({ MediaType.APPLICATION_JSON, MediaType.APPLICATION_XML})
public Response findMyEntityById(
        @PathParam("entityId") String id) 
{
  EntityRequest req = new EntityRequest();
  //similar stuff and sends the response back
  return response;
}

If I hit same rest url as POST request, it should return a HTTP 405 error.

This scenario is working fine for JSON requests but when I change request header to xml Accept:application/xml and Content-Type:application/xml, controller comes back with HTTP-500 error.