CopyOnWriteArraySet Vs just toArray()

[siteuser]

Hi Experts,

I would like to know your opinion on which one is better or preferred to invoke callback methods see below example.

Also is CopyOnWriteArraySet better than toArray(T[] ts) for this example, I feel toArray(T[] ts) is better.

What's your opinion?

interface SomeListener {
    void callBack();
}
//////////////
class AbstractService {
    protected List<SomeListener> listenerList;
    abstract init();
    addSomeListener(SomeListener listener) {
        listenerList.add(listener);
    }
    removeSomeListener(....) {...}
    abstract fireCallBack();
}
///////////////
class ToArrayService extends AbstractService {
    init() {
        listenerList = new ArrayList<SomeListener>();
    }

    fireCallBack() {
         SomeListener[] listeners = new SomeListener[listenerList.size()];
         listeners = (SomeListener[])listenerList.toArray(listeners);
        for(SomeListener listener : listeners) {
            listener.callBack();
        }
    }
}
/////////////
class CopyOnWriteArraySetService extends AbstractService {
    init() {
        listenerList = new CopyOnWriteArraySet<SomeListener>();
    }

    fireCallBack() {
        for(SomeListenerlistener : listenerList) {
            listener.callBack();
        }
    }
}

thanks in advance
siteuser

[siteuser]

I found my answer after reading the following:
http://book.javanb.com/java-threads-...-8-SECT-2.html

cheers