Question

I’m writing a REST service using Jersey. I have an abstract class Promotion that has an annotation:

@JsonTypeInfo(use = JsonTypeInfo.Id.CLASS)

Thanks to that, when I return a list of objects:

@GET
@Produces(MediaType.APPLICATION_JSON)
@Path("promotions/")
public List<Promotion> getClosestPromotions() {
List<Promotion> promotions = getPromotions(); //here I get some objects

return promotions;
}

I get a Json string with a “@class” field for every object in that list. But the problem is that if I return a Response:

@GET
@Produces(MediaType.APPLICATION_JSON)
@Path("promotions/")
public Response getClosestPromotions() {
List<Promotion> promotions = getPromotions(); //here I get some objects

return Response.ok().entity(promotions).build();
}

I’m getting almost the same list, but without additional “@class” field.
Why is that and what can I do to get a list with “@class” field returning a list in Response?
And by the way, surprisingly, it works when I return a Response with one Promotion object only given as an entity and I get that “@class” field.

Answer 1

Maybe you would want to try:

GenericEntity<Collection<Promotion>> genericEntity = 
           new GenericEntity<Collection<Promotion>>(promotions){};
return Response.ok().entity(genericEntity).build();