title: @JsonTypeInfo(use = JsonTypeInfo.Id.CLASS) not working when Response is returned
body: <p>I'm writing a REST service using Jersey. I have an abstract class Promotion that has an annotation:</p>
  
  <pre><code>@JsonTypeInfo(use = JsonTypeInfo.Id.CLASS)
  </code></pre>
  
  <p>Thanks to that, when I return a list of objects:</p>
  
  <pre><code>@GET
  @Produces(MediaType.APPLICATION_JSON)
  @Path("promotions/")
  public List&lt;Promotion&gt; getClosestPromotions() {
  List&lt;Promotion&gt; promotions = getPromotions(); //here I get some objects
  
  return promotions;
  }
  </code></pre>
  
  <p>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:</p>
  
  <pre><code>@GET
  @Produces(MediaType.APPLICATION_JSON)
  @Path("promotions/")
  public Response getClosestPromotions() {
  List&lt;Promotion&gt; promotions = getPromotions(); //here I get some objects
  
  return Response.ok().entity(promotions).build();
  }
  </code></pre>
  
  <p>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.</p>