Facebook SDK keeps crashing android app -

okay i'm trying implement facebook sdk android app. problem is, when use code explained within facebook documentation, app crashes no error messages.

heres code im using (from facebook documentation):

// start facebook login         session.openactivesession(this, true, new session.statuscallback()          {             // callback when session changes state               @override               public void call(session session, sessionstate state, exception exception)                {                 if (session.isopened())                  {                                // make request /me api                     request.executemerequestasync(session, new request.graphusercallback()                      {                         // callback after graph api response user object                         @override                         public void oncompleted(graphuser user, response response)                          {                             if (user != null)                              {                              }                         }                     });                 }               }         });