In case of Apple, device token is same for all apps in device. It just differentiate it with certificate. But what in case of android? Is device token for all apps is same or different?
No, Google Cloud Messaging device tokens (or more accurate Registration IDs or Registration Tokens) are different for each app on the same device.
BTW, even though I haven't tested it myself, I read that iOS device tokens are also different for each app on the same device starting in iOS7.