Do I need to authenticate user each time user uses my android app

I am creating an android application in which I need to show some data from server as user logged in. We are using facebook login to authenticate user. We are handling session with jsessionid. We cache the data in android local db and every time when user open the app we show the cache data and synch the data in background process. We are using gcm messaging to send notification to user.

My only concern is about user authentication. Do every time I need to authenticate user when he open my app or I can rely on jsessionid token that I received from server on authenticating the user for the every first time.

I checked the behaviour of gmail. It shows me data immediately when I click the app and seems that they do not send call at server to authenticate the user.

I am using Google app engine as backend.
What other parameters should I use with jsessionid to ensure user so that I can see the contents immediately he open android app

Regards

Rick

Source: http://facebook.stackoverflow.com/questions/14091009/do-i-need-to-authenticate-user-each-time-user-uses-my-android-app

did the groundhog see his shadow punxsutawney phil groundhog day ground hog groundhog day 2012 serrano staten island chuck