title: Strange "nameValuePairs" key appear when using Gson
body: <p>I am trying to rebuild an <code>Object</code> from its fields( i get the fields as a JSONObject), something like this:</p>
  
  <pre><code>JSONObject jObj = new JSONObject();  
  
  JSONObject jObj1 = new JSONObject(); 
  JSONObject jObj2 = new JSONObject(); 
  
  JSONObject jObj21 = new JSONObject(); 
  JSONObject jObj22 = new JSONObject(); 
  
  jObj1.put("jObj11", "value11");
  jObj1.put("jObj12", "value12");
  
  
  jObj21.put("jObj211", "value211"); // level 2 
  jObj21.put("jObj212", "value212");
  jObj21.put("jObj213", "value213");
  
  jObj22.put("jObj221", "value221");
  jObj22.put("jObj222", "value222");
  jObj22.put("jObj223", "value223");
  
  jObj2.put("jObj21", jObj21);  // level 1 
  jObj2.put("jObj22", jObj22);
  
  jObj.put("jObj1", jObj1); // level 0 
  jObj.put("jObj2", jObj2);
  </code></pre>
  
  <p>I use those lines to get Json from an <code>Obeject</code></p>
  
  <pre><code>GsonBuilder builder = new GsonBuilder();
  Gson gSon = builder.create();
  gSon.toJSon(jObj);
  </code></pre>
  
  <p>The <strong>Problem</strong> is when i parse the main <code>Object</code> ( jObj ) with Gson, i found an extra key named <code>"nameValuePairs"</code>. So why i get this key?</p>
  
  <p><strong>Notice</strong>:</p>
  
  <ul>
  <li>If i do : <code>jObj.toString();</code> on Log, this key disappear.</li>
  <li>If i do : <code>jObj.opt("nameValuePairs");</code> i have <em>Null</em> as result (like there is no key named "nameValuePairs").</li>
  </ul>
  
  <p>This is my actual result:</p>
  
  <p><img src="https://i.stack.imgur.com/NTLiK.png" alt="enter image description here"></p>
  
  <p>And this is what i expect to have:</p>
  
  <p><img src="https://i.stack.imgur.com/WUC8m.png" alt="enter image description here"></p>
  
  <p>I found <a href="https://stackoverflow.com/questions/26022133/how-can-i-delete-the-namevaluepairs-key-from-the-jsonobject">something similar to my problem</a>, but it doesn't help.</p>
  
  <p>Is there someone who have a solution/workaround or can explain me the origin of this key?</p>
  
  <p>Thanks.</p>