Android components Activity, Service, BroadcastReceiver, Content Provider

Content Provider: http://www.codexpedia.com/android/android-content-provider-example/

BroadcastReceiver: http://www.codexpedia.com/android/android-broadcastreceiver-example/

Services:

http://www.codexpedia.com/android/android-service/

http://www.codexpedia.com/android/android-intent-service/

http://www.codexpedia.com/android/android-bound-service/

http://www.codexpedia.com/android/android-restart-app-by-service/