Android: How to avoid that clicking on a Notification calls onCreate()

In my application I notify the user with notifications, if something special happens:

public void triggerNotification(String msg) {
        notificationManager = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
        Intent contentIntent = new Intent(this, ABC.class);
        Notification notification = new Notification(R.drawable.icon, msg, System.currentTimeMillis());
        notification.setLatestEventInfo(this, "ABC", msg, PendingIntent.getActivity(this.getBaseContext(), 0, contentIntent, PendingIntent.FLAG_CANCEL_CURRENT));
        notification.flags = Notification.FLAG_AUTO_CANCEL;
        notificationManager.notify(notificationCounter, notification);
        notificationCounter++;
}

If the user clicks on the Notification, the onCreate() method is called. But I want that a specific method in my app is called, or if the app is not in the foreground, that it is brought back to the foreground.

I know there are lots of tutorials that explain how to handle notifications, but I just don't understand them completely and wasn't ever able to implement the things like I'd like to.