package slidenerd.javaoop; /** * Created by Microsoft on 10/6/2015. */ public class SuperClassReferenceVariable { public static void main(String[] args) { Person p1 = new Person(); Person p2 = new Person(); Student s1 = new Student(); Student s2 = new Student(); // All info of Person present in Student Person p3 = new Student(); // Without typecast // But all info of Student needed is // not present in Person class Student s3 = (Student) p3; // works System.out.println(s3); } } class Person { String name; int age; String address; } class Student extends Person { int rollnumber; int marks; }