title: Gson.fromJson not failing if some fields are not given even though marked as @NonNull
body: <p>I have a POJO defined as follows:</p>
  
  <pre><code>@Value
  public class Abc {
  
      @NonNull
      private final String id;
  
      @NonNull
      private final Integer id2;
  
      @NonNull
      private final List&lt;String&gt; data;
  
      @NonNull
      private final String otherData;
  }
  </code></pre>
  
  <p>When I am doing,</p>
  
  <pre><code>GSON.fromJson(str, Abc.class);
  </code></pre>
  
  <p>with str as:</p>
  
  <pre><code>{
  "id": "dsada",
  "id2": 12,
  "data": ["dsadsa"]
  }
  </code></pre>
  
  <p>In this, there is no otherData field. Even then, GSON.fromJson is not failing. Why is it so? Then, is there any significance of marking the field as @NonNull?</p>