title: Deserialize List<Interface> with jackson
body: <p>I want to deserialize json to class Foo:</p>
  
  <pre><code>class Foo {
     List&lt;IBar&gt; bars;
  }
  
  interface IBar {
     ...
  }
  
  class Bar implements IBar {
     ...
  }
  </code></pre>
  
  <p>IBar has two implementations, but when deserializing I always want to use the first implementation. (This should ideally make the problem easier, because there is no runtime type checking required)</p>
  
  <p>I am sure I can write custom deserializers, but felt there must be something easier.</p>
  
  <p>I found this annotation, which works perfectly when there is no list. </p>
  
  <pre><code>@JsonDeserialize(as=Bar.class)
  IBar bar;
  
  List&lt;IBar&gt; bars; // Don't know how to use the annotation here.
  </code></pre>