Abstract class extended form and called by object of its class

abstract class A { abstract void display(); } class B extends A { void display() { System.out.println("display in B"); } } class C extends A { void display() { System.out.println("display in C"); } } class D extends A { void display() { System.out.println("display in D"); } } class Eleven { public static void main(String args[]) { B obj1=new B(); obj1.display(); C obj2=new C(); obj2.display(); D obj3=new D(); obj3.display(); } }