Sender class - GCM Example - Java App engine

Question

I use the google example (gcm-demo-appengine - Google Demo)

but i think there may be some problems with google source code, when i run it, it throws

java.lang.NoClassDefFoundError: com/google/android/gcm/server/Sender
at cloud.spam.filter.server.SendMessageServlet.newSender(SendMessageServlet.java:63)
at cloud.spam.filter.server.SendMessageServlet.init(SendMessageServlet.java:54)

There is some problems with the sender class (seriously?)
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.
Thank you very much.

Answer 1

Make sure your gcm-server.jar is in the war/WEB-INF/lib folder of your project. Nothing else will do