title: Serialize vertx JsonObject using Jackson
body: <p>I'm using <strong>vertx</strong> and <strong>Jackson</strong> in my development. In one of my classes, I got a field of type <code>JsonObject</code>, something like this:</p>
  
  <pre><code>class User
    private String name;
    private JsonObject details;
  </code></pre>
  
  <p>This <em>details</em> field can contain other JsonObjects or JsonArrays, e.g.:
  <code>{"details": [{"street": "Broadway"}, {"building": 20}]}</code><br>
  I don't have a dedicated class of this structure, as far as there's no fixed structure and it can vary.<br>
  <em>details</em> object is being created in the way like this:</p>
  
  <pre><code>JsonObject details = new JsonObject().put("name", "value").put("another", "another")
  </code></pre>
  
  <p>This aproach allows me to store details of any structure inside my code. As far as I don't need to manipulate this data on my backend, I don't want to create a special structure for it.<br>
  Everything works fine until I'm trying to serialize this <code>JsonObject</code> using <strong>Jackson</strong>. Unfortunately, instead of beatiful JSON string, Jackson gives me <code>map</code> object serialized with all map's additional fields.  </p>
  
  <p>How can I serialize <code>JsonObject</code> of <strong>vertx</strong> using <strong>Jackson</strong>?</p>