title: How to ignore certain fields with Jackson's ObjectMapper.readerForUpdating
body: <p>I'm using Jackson 2.7.0</p>
  
  <p>I'm trying to ignore <code>encodingType</code> when updating an existing object with some new values: </p>
  
  <pre><code>ObjectMapper om = new ObjectMapper();
  om.readerForUpdating(message).readValue(messageSubset);
  </code></pre>
  
  <p><code>message</code> contains a value for <code>encodingType</code>.<br>
  <code>messageSubset</code> (JSON-string) does not contain an entry (no key-value) for <code>encodingType</code>.</p>
  
  <p>What I've tried:</p>
  
  <ul>
  <li>For the ObjectMapper: 
  
  <ul>
  <li><code>om.setSerializationInclusion(Include.NON_EMPTY);</code></li>
  </ul></li>
  <li>On the message class: 
  
  <ul>
  <li><code>@JsonIgnoreProperties(ignoreUnknown = true)</code></li>
  <li><code>@JsonIgnoreProperties(value = { "encodingType" })</code></li>
  <li><code>@JsonInclude(Include.NON_EMPTY)</code></li>
  <li><code>@JsonInclude(Include.NON_NULL)</code></li>
  </ul></li>
  <li>On the field and on the getters/setters:
  
  <ul>
  <li><code>@JsonInclude(Include.NON_EMPTY)</code></li>
  <li><code>@JsonInclude(Include.NON_NULL)</code></li>
  <li><code>@JsonIgnore</code></li>
  <li><code>@JsonSerialize(include=JsonSerialize.Inclusion.NON_NULL)</code></li>
  </ul></li>
  </ul>
  
  <p>Non of the above work! Any help? <br>
  I suppose this has something to do with readerForUpdating and/or the fact that one of them is being updated.</p>