You don't need to convert the Map to get size() or get(). Maps and Lists are totally different. If you really want to iterate through the Map use the entrySet() method which gives a Set you can iterate through.
That is a very good suggestion, Javier; it only needs a type declaration which would be List<E>. Please keep helping, but we usually try not to post on such an old topic; we have a badly-named FAQ about that.
Please keep posting, but watch the dates on the previous posts.