Explain subclasses and polymorphism, JAVA Programming

Assignment Help:

Explain Subclasses and Polymorphism ?

Car and Motorcycle are subclasses of MotorVehicle. If you instantiate a Car or a Motorcycle along with new, you can use in which object anywhere you can use a MotorVehicle, since cars are motor vehicles. As same you can use a Motorcycle anywhere you can use a MotorVehicle. This use of a subclass object in place of a superclass object is the starting of polymorphism. I'll say more about polymorphism later.

The converse is not true. While all cars are motor vehicles, not all motor vehicles are cars. A few are motorcycles. Thus if a method expects a Car object you shouldn't provides it a MotorVehicle object instead.

Remember that I said you shouldn't provide a method in which expects a Car a MotorVehicle. I didn't say you couldn't. Objects can be cast into their subclasses. This is useful while using data structures like Vectors that only handle generic objects. It's up to the programmer to remain track of what kind of object is stored in a Vector, and to use it accordingly.

The proper choice of classes and subclasses is a skill learned primarily by experience. There are often different ways to define classes.
toString() as example of polymorphism


Related Discussions:- Explain subclasses and polymorphism

Convert an existing flash file into html5, REQUIREMENT: We are seeking a si...

REQUIREMENT: We are seeking a simple tool that will convert an existing flash file (.SWF) into HTML5. Our purpose is to convert small flash games into html5 games. Please NOTE: We

What is dispatchaction, The DispatchAction class is used to group related a...

The DispatchAction class is used to group related actions into single class. Using this class, you can have a method for every logical action compared than a one executes method. T

How to returning multiple values from methods, How to Returning Multiple Va...

How to Returning Multiple Values From Methods ? It is not probable to return more than one value from techniques. You cannot, for example, return the licensePlate, speed and m

What is a proxy, A proxy is an object that is formed after applying advice ...

A proxy is an object that is formed after applying advice to a target object. When you think of client objects the target object and the proxy object are the similar.

Define the difference between stringbuffer and string class, Define the dif...

Define the difference between StringBuffer and String class ?

Explain pop, SMTP (Simple Mail Transfer Protocol) permits two mail servers ...

SMTP (Simple Mail Transfer Protocol) permits two mail servers to communicate using a easy language, and gives a step-by-step protocol for exchanging information. SMTP delivers m

Design a program for robot, Assume all the obstacles are of height 4 units ...

Assume all the obstacles are of height 4 units and the blocks are of heights 1 (bottom), 2 (top), 1 and 2 (top) units respectively.  Complete the control() method of the RobotContr

Develop an e-commerce website, Develop an E-commerce website I prefer th...

Develop an E-commerce website I prefer this website to be coded with JAVA since I have heard this is safer than PHP is. Though, if this is not possible I am willing to go with P

On bluej, I need to write a program to assign values to the variable age an...

I need to write a program to assign values to the variable age and print the reason as major or minor.

Array, public class Tester { static void test(int[] a) { int[] b = new in...

public class Tester { static void test(int[] a) { int[] b = new int[2]; a = b; System.out.print(b.length); System.out.print(a.length); } public static void main(String[] arg

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd