Android Question Keep service running without wake lock

[Devv]

i need my service to keep running even when the device sleep (so i can send commands to my device using httputlis), so i searched around and i found that wake lock would not let the device sleep, which worked for me but it made the battery empty very fast.

how could apps like whatsapp not use wake lock and you can still revive whatsapp messages when your device is at sleep mode ?

 

[DonManfred]

how could apps like whatsapp

They uses GCM push notifications

 

[Devv]

They uses GCM push notifications

GCM requires Google services, it tried whatsapp on more than one device without google services and it worked perfectly, so i don't think whatsapp uses GCM

 

[b4auser1]

According the article
http://gizmostorm.com/how-to-fix-whatsapp-push-notification-delay-on-android/
whatsapp uses Google’s Cloud Messaging Service.