The SignalR with the Java library is a great choice for realtime communication. Though it is possible to subscribe to hub on the onCreate and to close it. But what happens when the application is killed ( manually or automatically) or even the activity is dead. One solution is to use a service - that is basicly same as creating a GCM, OR the other one is to make juggling with push notifications, and send them also and than synchronize what is already sent to the user(bad thing)
Suggestions ?