package abstractKey; /* If a class is not having any abstract method * then it is possible to have no abstract method * * But if a class have one or more abstract method * then class should be abstract. * */ abstract class Car{ abstract void start();// Abstract method must be implemented // in subclasses } class Audi extends Car{ @Override void start(){ System.out.println("Audi Car "); } } class BMW extends Car{ @Override void start(){ System.out.println("BMW Car"); } } class Drive{ void drive(Car c) { c.start(); } } public class Example1 { public static void main(String[] args) { Drive d=new Drive(); d.drive(new Audi()); d.drive(new BMW()); } }