1 package sample.vector; 2 3 public class Sample extends java.util.Vector { add(X e)4 public void add(X e) { 5 super.addElement(e); 6 } 7 at(int i)8 public X at(int i) { 9 return (X)super.elementAt(i); 10 } 11 } 12 13 class X { 14 } 15