Push уведомления

public class PostService extends Service {
 
 
 
private final int NOTIFICATION_ID=127;
 
    NotificationManager nm;
 
    @Override
    public void onCreate() {
        super.onCreate();
        nm = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
    }
 
    public int onStartCommand(Intent intent, int flags, int startId) {
 
        sendNotif();
        return super.onStartCommand(intent, flags, startId);
    }
 
    void sendNotif() {
 
        Notification.Builder builder = new Notification.Builder(getApplicationContext());
        AlarmManager am = (AlarmManager) getSystemService(ALARM_SERVICE);
 
        Intent intent = new Intent(this, MainActivity.class);
        PendingIntent pIntent = PendingIntent.getActivity(this, 0, intent, 0);
 
        am.setRepeating(AlarmManager.ELAPSED_REALTIME,
                SystemClock.elapsedRealtime() + 3000, 5000, pIntent);
 
 
        builder
                .setContentIntent(pIntent)
        .setSmallIcon(R.drawable.ic_launcher)
        .setLargeIcon(BitmapFactory.decodeResource(getApplication().getResources(),R.drawable.ic_launcher))
        .setTicker("Новый месадж")
        .setWhen(System.currentTimeMillis())
        .setAutoCancel(true)
        .setContentTitle("Привет")
        .setContentText("Много плюх");
 
        Notification notification = builder.build();
 
 
        nm.notify(NOTIFICATION_ID, notification);
    }
 
 
 
 
    public PostService() {
    }
 
    @Override
    public IBinder onBind(Intent intent) {
        // TODO: Return the communication channel to the service.
        throw new UnsupportedOperationException("Not yet implemented");
    }
}

int NOTIFICATION_ID = 0;
void sendNotif() {
        NOTIFICATION_ID ++;
        Notification.Builder builder = new Notification.Builder(getApplicationContext());
        AlarmManager am = (AlarmManager) getSystemService(ALARM_SERVICE);
 
        Intent intent = new Intent(this, MainActivity.class);
        PendingIntent pIntent = PendingIntent.getActivity(this, 0, intent, 0);
 
        am.setRepeating(AlarmManager.ELAPSED_REALTIME,
                SystemClock.elapsedRealtime() + 3000, 5000, pIntent);
 
 
        builder
                .setContentIntent(pIntent)
        .setSmallIcon(R.drawable.ic_launcher)
        .setLargeIcon(BitmapFactory.decodeResource(getApplication().getResources(),R.drawable.ic_launcher))
        .setTicker("Новый месадж")
        .setWhen(System.currentTimeMillis())
        .setAutoCancel(true)
        .setContentTitle("Привет")
        .setContentText("Много плюх");
 
        Notification notification = builder.build();
        nm.notify(NOTIFICATION_ID, notification);
    }

Random random = new Random();
int rand_id = random.nextInt();
nm.notify(rand_id , notification);