Question

At the moment inside the class I have ArrayList which the objects are stored in when they are added to the club. I also have a integer which would be auto incremented once a object has been added to the ArrayList. However, I am unsure how I would be able to add the registration ID with the player object in the ArrayList.

Answer 1

It is not completely clear from your description what exactly you are trying to do, so I am guessing something like this:

public synchronized void registerPlayer(Player p)
{
    p.setRegistrationId(registrationID++);
    players.add(p);
}