MyFirebaseMessagingService.onNewToken() is never called

[i--storm]

According to FCM documentation:
"On initial startup of your app, the FCM SDK generates a registration token for the client app instance. If you want to target single devices or create device groups, you'll need to access this token by extending FirebaseMessagingService and overriding onNewToken."
You will not receive token in onNewToken inside MyFirebaseMessagingService if in already generated for your app.
Routine inside MainActivity should be implemented to get current token
https://firebase.google.com/docs/cloud-messaging/android/first-message#retrieve-the-current-registration-token