After customizing few modules i planned to implement firebase in the project for sending push notification.
What you need to do is
1. Go to Tools -> Firebase->Cloud Messaging -> Import / Create New Project
2. Once the project is created in the Google App Engine, you need to sync the Gradle
Whenver you run the project, the app will get the firebase token, and you can get the firebase token by FirebaseInstanceId.getInstance().getToken()
You can test it by consoling it
3. Next thing you need to do is, sending push notification on your device.
You can use send it throught the Firebase console like the image given below