notificationManager.kt

val notificationManager = NotificationManagerCompat.from(context)

// internally it does the following

public static NotificationManagerCompat from(@NonNull Context context) {
    return new NotificationManagerCompat(context);
}

private NotificationManagerCompat(Context context) {
    mContext = context;
    mNotificationManager = (NotificationManager) mContext.getSystemService(
            Context.NOTIFICATION_SERVICE);
}