title: Enable EMPTY_ELEMENT_AS_NULL in Camel 3 XML DSL
body: <p>I've found <a href="https://github.com/FasterXML/jackson-dataformat-xml/issues/411" rel="nofollow noreferrer">here</a> that the default behaviour for <strong>FromXmlParser.Feature.EMPTY_ELEMENT_AS_NULL</strong> has changed from true (2.9 - 2.11) to false (2.12 onwards), so from that version no automatic coercion is done from empty elements like  into null.</p>
  <p>I was using Apache Camel 2.25 and that version had this feature enabled by default but now, with this change, is disabled in Camel 3.x. How can I enable it in back in Camel 3 using XML DSL? I know using XMLMapper is easy enough:</p>
  <pre class="lang-java prettyprint-override"><code>XmlMapper xmlMapper = new XmlMapper();
  xmlMapper.configure(FromXmlParser.Feature.EMPTY_ELEMENT_AS_NULL, true);
  </code></pre>
  <p>But in Camel XML DSL the <a href="https://camel.apache.org/components/3.14.x/dataformats/jacksonxml-dataformat.html#_enabling_or_disable_features_using_jackson" rel="nofollow noreferrer">allowed enums</a> are only the ones from SerializationFeature, DeserializationFeature and MapperFeature. I've tried with some of them but with no luck.</p>
  <pre class="lang-xml prettyprint-override"><code>&lt;unmarshal&gt;
     &lt;jacksonxml disableFeatures=&quot;FAIL_ON_UNKNOWN_PROPERTIES&quot;
        enableFeatures=&quot;ACCEPT_EMPTY_STRING_AS_NULL_OBJECT,ACCEPT_EMPTY_ARRAY_AS_NULL_OBJECT&quot;
        unmarshalTypeName=&quot;com.my.class.Result&quot; 
        include=&quot;NON_NULL&quot; /&gt;
  &lt;/unmarshal&gt;
  </code></pre>