Android Tutorials : Firebase Push Notification Tutorial.
You need to paste your google-servies.json file under "androidbash_firebase_push_notifications/app/" folder before you try out the application. You can get it from Firebase console.
Visit Tutorial : http://androidbash.com/firebase-push-notification-android/
Firebase cloud messaging (FCM) is a new version of Google Cloud Messaging (GCM). Using FCM you can send notification messages to your client application in order to drive user engagement. With FCM, you can send two types of messages to the client app: Notification messages and Data messages, A notification message is the more lightweight option, with a 2KB limit and a predefined set of user-visible keys. Data messages let developers send up to 4KB of custom key-value pairs. Notification messages can contain an optional data payload, which is delivered when users tap on the notification. Use notification messages when you want Firebase cloud messaging (FCM) to handle displaying a notification on your client app’s behalf. Use data messages when you want to process the messages on your client app.
Visit Tutorial : http://androidbash.com/firebase-push-notification-android/