title: Convert Json to Object when field name begin with a dot
body: <p>I'm trying to make a conversion from JsonElement to Object using Gson.
  The problem is that JsonObject have two fields which the name begins with a dot, and these field are not mapped when I use <strong>gson.fromJson</strong> method.</p>
  
  <p>This is the Json object (a token object):</p>
  
  <pre><code>{
     "access_token":"boQtj0SCGz2GFGz[...]",
     "token_type":"bearer",
     "expires_in":1209599,
     "userName":"gonzalo",
     ".issued":"Mon, 14 Oct 2014 06:53:32 GMT",
     ".expires":"Mon, 28 Oct 2014 06:53:32 GMT"
  }
  </code></pre>
  
  <p>And this is the target class:</p>
  
  <pre><code>private class BearerToken{
          public String access_token;
          public String token_type;
          public String expires_in;
          public String userName;
          public Date issued;
          public Date expires;
  
          public BearerToken(){
          }
      }
  </code></pre>
  
  <p>This is my code and results:</p>
  
  <pre><code> HttpResponse resp = httpClient.execute(post); // request to server
   String respStr = EntityUtils.toString(resp.getEntity()); // json token
   JsonParser parser = new JsonParser();
   sonElement jsonElement =  parser.parse(respStr);
   BearerToken token = new BearerToken();             
   Gson gson = new Gson();
   token = gson.fromJson(jsonElement, token.getClass());
  </code></pre>
  
  <p><strong>respStr:</strong></p>
  
  <pre><code>{"access_token":"d7NDuC7accTA[....]",
  "token_type":"bearer",
  "expires_in":1209599,
  "userName":"43344",
  ".issued":"Tue, 30 Sep 2014 16:03:17 GMT",
  ".expires":"Tue, 14 Oct 2014 16:03:17 GMT"}
  </code></pre>
  
  <p><strong>token:</strong></p>
  
  <p><img src="https://i.stack.imgur.com/zmQb9.jpg" alt="enter image description here"></p>
  
  <p>Fields <strong>.expires</strong> and <strong>.issued</strong> are always <strong>null</strong></p>
  
  <p>Any thoughts?
  Thanks.</p>