object orientation in java

1class Person {
2 void walk() {
3  System.out.println(“Can Run….”);
4 }
5}
6class Employee extends Person {
7 void walk() {
8  System.out.println(“Running Fast…”);
9 }
10 public static void main(String arg[]) {
11  Person p = new Employee(); //upcasting
12  p.walk();
13 }
14}