How can we generate the Notifications In android

private static void generateNotification(Context context, String message,int receiverId) {
        int icon = R.drawable.on;
        long when = System.currentTimeMillis();
        NotificationManager notificationManager = (NotificationManager)
        context.getSystemService(Context.NOTIFICATION_SERVICE);
        Notification notification = new Notification(icon, message, when);
        String title = context.getString(R.string.title);
        Intent notificationIntent = new Intent(context, Activity_name.class);
        // set intent so it does not start a new activity
        notificationIntent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_SINGLE_TOP );
        PendingIntent intent =PendingIntent.getActivity(context, 0, notificationIntent,PendingIntent.FLAG_UPDATE_CURRENT);
        notification.setLatestEventInfo(context, title, message, intent);
        notification.flags |= Notification.FLAG_AUTO_CANCEL;    
        // Play default notification sound
        notification.defaults |= Notification.DEFAULT_SOUND;
        notification.defaults |= Notification.DEFAULT_VIBRATE;
        notificationManager.notify(receiverId, notification);  

    }