Intent service = new Intent(getApplicationContext(), MyService.class);
getApplicationContext().startService(service);

public class MyService extends Service {

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        // TODO do something useful
        HFLAG = true;
        //smsHandler.sendEmptyMessageDelayed(DISPLAY_DATA, 1000);
        return Service.START_NOT_STICKY;
    }

    @Override
    public IBinder onBind(Intent intent) {
        // TODO for communication return IBinder implementation
        return null;
    }
}

<service
    android:name=".MyService"
    android:icon="@drawable/ic_launcher"
    android:label="@string/app_name" >
</service>

public int onStartCommand(Intent intent, int flags, int startId) {
        return START_STICKY;
}

Intent intent = new Intent(this, PowerMeterService.class);
startService(intent);

public class MyBinder extends Binder {
        public MyService getService() {
                return MyService.this;
        }
}

private ServiceConnection m_serviceConnection = new ServiceConnection() {
        public void onServiceConnected(ComponentName className, IBinder service) {
                m_service = ((MyService.MyBinder)service).getService();
        }

        public void onServiceDisconnected(ComponentName className) {
                m_service = null;
        }
};

Intent intent = new Intent(this, MyService.class);
        bindService(intent, m_serviceConnection, BIND_AUTO_CREATE);

private void addNotification() {
        // create the notification
        Notification.Builder m_notificationBuilder = new Notification.Builder(this)
                .setContentTitle(getText(R.string.service_name))
                .setContentText(getResources().getText(R.string.service_status_monitor))
                .setSmallIcon(R.drawable.notification_small_icon);

        // create the pending intent and add to the notification
        Intent intent = new Intent(this, MyService.class);
        PendingIntent pendingIntent = PendingIntent.getActivity(this, 0, intent, 0);
        m_notificationBuilder.setContentIntent(pendingIntent);

        // send the notification
        m_notificationManager.notify(NOTIFICATION_ID, m_notificationBuilder.build());
}

android:launchMode="singleTop"

startForeground(NOTIFICATION_ID, m_notificationBuilder.build());

<service
  android:name="WordService"
  android:process=":my_process"
  android:icon="@drawable/icon"
  android:label="@string/service_name"
  >
</service>

public int onStartCommand(Intent intent, int flags, int startId) {
    return START_STICKY;
}

android:launchMode="singleTop"