title: Jackson SimpleAbstractTypeResolver for List<Interface>
body: <p>I have an object that is comprised of interfaces that I need to deserialize using Jackson. Due to the design of the system I cannot specify any annotations in the interface so I need to add the required resolver information to the <code>ObjectMapper</code>. My object has the following:</p>
  
  <pre><code>private Alarm alarm; // Alarm is an interface
  private List&lt;Extra&gt; extra; // Extra is an interface
  </code></pre>
  
  <p>Now I can take care of the Alarm relatively easily using an <code>AbstractTypeResolver</code>:</p>
  
  <pre><code>SimpleAbstractTypeResolver resolver = new SimpleAbstractTypeResolver();
  resolver.addMapping(Alarm.class, AlarmImpl.class);
  
  SimpleModule module = new SimpleModule();
  module.setAbstractTypes(resolver);
  
  mapper.registerModule(module);
  
  mapper.readValue(json, new TypeReference&lt;List&lt;Engine&gt;&gt;() {});
  </code></pre>
  
  <p>That works great. However, adding the <code>Extra</code> resolver in the same way doesn't work:</p>
  
  <pre><code>resolver.addMapping(Extra.class, ExtraImpl.class);
  </code></pre>
  
  <p>Any suggestions on how I should be applying it for a list?</p>