title: Json: Add object to array
body: <p>I am using javax.json library to use Json in Java. 
  I am trying to add JsonObject in JsonArray, for example:</p>
  
  <pre><code>[
      { "some_stuff": "stuff" },
      { "some_stuff": "stuff" }
  ]
  </code></pre>
  
  <p>I need to add to this array next object with same keys as in example, but i have frozen at<code>array.add();</code></p>
  
  <pre><code>JsonObject jsonObject = Json.createObjectBuilder()
      .add("some_stuff", "stuff")
          .build();
  
  JsonArray array = jsonReader.readArray();
  array.add(jsonObject); // UnsupportedOperationException
  </code></pre>