import java.util.*;class GD6 {　　public static void main(String[] args) {ArrayList<Person> a = new ArrayList<Person>();a.add(new Person("a"));a.add(new Person("b"));a.add(new Person("c")); ArrayList<Stu> al1 = new ArrayList<Stu>();al1.add(new Stu("A"));al1.add(new Stu("B"));al1.add(new Stu("C"));printCln(a);}public static void printCln(ArrayList<Person> al){Iterator<Person> it = al.iterator();while(it.hasNext()){System.out.println(it.next().getName());}}}class Person{String name;String getName(){return this.name;}Person(String name){this.name = name;}}class Stu extends Person{String name;Stu(String name){super(name);}}