HashSet<String> hashSet = new HashSet<String>();

        Iterator<String> iterator = hashSet.iterator();

        while(iterator.hasNext())
        {
            System.out.println(iterator.next());
        }

        HashMap<String, Integer>hashMap=new HashMap<String, Integer>();
        Set<Entry<String,Integer>> entradas = hashMap.entrySet();

        Iterator<Entry<String,Integer>>iterator2 = entradas.iterator();

        while (iterator2.hasNext())
        {
            Entry<String,Integer> aux = iterator2.next();
            System.out.println(aux.getKey());
            System.out.println(aux.getValue());
        }