title: Unable to Execute code from Android Docs
body: <p>//This is the class with constructor having argument(DownloadCallback)</p>
  
  <p>private class DownloadTask extends AsyncTask {</p>
  
  <pre><code>private DownloadCallback&lt;String&gt; mCallback;
  
  DownloadTask(DownloadCallback&lt;String&gt; callback) {
      setCallback(callback);
  }
  
  void setCallback(DownloadCallback&lt;String&gt; callback) {
      mCallback = callback;
  }
  </code></pre>
  
  <p>// creating object of Download</p>
  
  <pre><code>* Start non-blocking execution of DownloadTask.
   */
  public void startDownload() {
      cancelDownload();
      mDownloadTask = new DownloadTask();
      mDownloadTask.execute(mUrlString);
  }
  </code></pre>
  
  <p>As we can see the creation of new Object requires argument, but this code which was in google Android Documentations doesnt provide any. I am stuck this one error
  <a href="https://developer.android.com/training/basics/network-ops/connecting" rel="nofollow noreferrer">https://developer.android.com/training/basics/network-ops/connecting</a></p>