Notificationservice.java

public class NotificationsService extends FirebaseMessagingService {
    @Override     public void onMessageReceived(RemoteMessage remoteMessage) {         if (remoteMessage.getNotification() != null) {             // 1 - Get message sent by Firebase             String message = remoteMessage.getNotification().getBody();             //2 - Show message in console             Log.e("TAG", message);         }     } }