push notification samples

https://blog.serverdensity.com/how-to-build-an-apple-push-notification-provider-server-tutorial/

http://developer.android.com/google/gcm/gs.html

https://blog.serverdensity.com/how-to-build-an-apple-push-notification-provider-server-tutorial/

MQTT tecnique 

http://push-notification.org/

http://stackoverflow.com/questions/1378671/push-notifications-in-android-platform

http://www.pushlets.com/

http://mqtt.org/

http://stackoverflow.com/questions/14474273/push-notification-for-java-web-app

http://dalelane.co.uk/blog/?p=938

http://deacon.daverea.com/

http://www.pubnub.com/tutorial/java-push-api

http://code.google.com/p/javapns/wiki/PushNotificationAdvanced

http://stackoverflow.com/questions/1243066/does-android-support-near-real-time-push-notification/