title: No Source Code is available for type java.text.SimpleDateFormat: GWT Compilation Error
body: <p>I was trying to make a GWT application. Then I got some errors when using SimpleDateFormat class in <strong><em>client and shared side</em></strong>.</p>
  
  <pre><code>[ERROR] [gwtfirst] Line 381: No source code is available for type java.text.SimpleDateFormat; did you forget to inherit a required module?
  </code></pre>
  
  <p>following is my code in client side:</p>
  
  <pre><code>SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); 
  Window.alert(sdf.format(usersList.get(30).getCreatedate()));
  </code></pre>
  
  <p>But I can use SimpleDateFormat with server side...
  I'm wondering if I can't use SimpleDateFormat in client or shared side?</p>