import java.util.Set; import java.util.HashSet; import java.util.List; import java.util.ArrayList; import java.util.Collection; import java.util.ListIterator; public class HelloWorld { public static void main(String []args) { Set <String>mySet = new HashSet<String>(); mySet.add("first string"); mySet.add("second string"); mySet.add("third string"); mySet.add("first string"); for (String s: mySet) System.out.println(s); List <String>myList = new ArrayList<String>(); myList.add("first string"); myList.add("second string"); myList.add("third string"); myList.add(0, "new first string"); myList.add("second string"); System.out.println("--------------------"); for (ListIterator <String>it = myList.listIterator(); it.hasNext();) System.out.println(it.next()); System.out.println("--------------------"); for (ListIterator <String>it = myList.listIterator(myList.size()); it.hasPrevious();) System.out.println(it.previous()); } }