title: JAX-RS change json serializer
body: <p>I want to change my serializer to jackson, so I could change timestamp format, i tried like this:</p>
  
  <pre><code>@Provider
  @Produces(MediaType.APPLICATION_JSON)
  public class JacksonConfig
          implements ContextResolver&lt;ObjectMapper&gt; {
  
      private final ObjectMapper objectMapper;
  
      public JacksonConfig() {
          objectMapper = new ObjectMapper();
          objectMapper.setDateFormat(new ISO8601DateFormat());
          objectMapper.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS,
                  false);
      }
  
      @Override
      public ObjectMapper getContext(Class&lt;?&gt; objectType) {
          return objectMapper;
      }
  }
  </code></pre>
  
  <p>and in ApplicationConfig :</p>
  
  <pre><code>    resources.add(com.rfid.server.helpers.JacksonConfig.class);
  </code></pre>
  
  <p>It didn't work, I still get timestamps formatted like his: <strong>2014-12-12T17:52:33.35031+02:00"</strong></p>
  
  <p>I tried debugging <code>JacksonConfig</code>, breakpoint comes to the constructor, but not <code>getContext</code> method</p>