title: Sender class - GCM Example - Java App engine
body: <p>I use the google example (gcm-demo-appengine - <a href="http://developer.android.com/guide/google/gcm/demo.html" rel="noreferrer">Google Demo</a>)</p>
  
  <p>but i think there may be some problems with google source code, when i run it, it throws </p>
  
  <blockquote>
    <p><br/>java.lang.NoClassDefFoundError: com/google/android/gcm/server/Sender
    <br/>at cloud.spam.filter.server.SendMessageServlet.newSender(SendMessageServlet.java:63)
    <br/>at cloud.spam.filter.server.SendMessageServlet.init(SendMessageServlet.java:54)</p>
  </blockquote>
  
  <p>There is some problems with the sender class (seriously?)
  <br/>Can we replace sender class with something else? This is the first time I use GCM thus I have no idea how important sender class is and what it is used for.
  <br/>Thank you very much.</p>