iterator사용법

//한 타입만 넣을수있다. Integer를 집어넣거나 하면 안됨, JDK1.5이상

            Collection<String> collection = new ArrayList<String>();

            collection.add("hello");

            collection.add("world");

            collection.add("!!");

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

            while(iterator.hasNext()){

                  String str =  iterator.next();

                  System.out.println(str);

                 

            }