title: How to check "isEmpty()" in Gson JsonObject?
body: <p>I used the Google Gson API to construct JSON. When I initialized a JsonObject with:</p>
  
  <pre><code>JsonObject json = new JsonObject();
  </code></pre>
  
  <p>and print it out, it was in fact <code>{}</code>.</p>
  
  <p>I tried to exclude the "empty" JSON, i.e. the <code>{}</code> ones that were not added any properties. But I could not find a method resembling <code>isEmpty()</code> in the Gson API.</p>
  
  <p>How can I find out the "empty" JSON with Gson API?</p>