GcmListenerService Base class for communicating with Google Cloud Messaging. 
GcmNetworkManager Class to create apps with robust "send-to-sync", which is the mechanism to sync data with servers where new information is available. 
GcmPubSub GcmPubSub provides a publish-subscribe model for sending GCM topic messages. 
GcmReceiver WakefulBroadcastReceiver that receives GCM messages and delivers them to an application-specific GcmListenerService subclass. 
GcmTaskService Implemented by the client application to provide an endpoint for the GcmNetworkManager to call back to when a task is ready to be executed. 
GoogleCloudMessaging GoogleCloudMessaging (GCM) enables apps to communicate with their app servers using simple messages. 
OneoffTask A task that will execute once,at some point within the specified window. 
PeriodicTask A periodic task is one that will recur at the specified interval, without needing to be rescheduled. 
Task Encapsulates the parameters of a task that you will schedule on the GcmNetworkManager
Task.Builder Builder object to construct these tasks before sending them to the network manager. 
TaskParams Container of parameters handed off to the client app in onRunTask(TaskParams)