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

I clicker, i am to find 75% of i clicker score.Each correct answer is worth...

i am to find 75% of i clicker score.Each correct answer is worth 2points and an incorrect 1point. Express grade as a percentage (i.e the max is 100%). e.g 1 no i clicker question

Jzebra integration into open erp web client, JZEBRA Integration into (Open ...

JZEBRA Integration into (Open ERP) Web Client Local Spooling/Printing to Local Print Device on ERP Client side Project Description: JZEBRA Integration into Open ERP Web Clien

Develop a geonetwork template, Develop a GeoNetwork Template Project Des...

Develop a GeoNetwork Template Project Description: Want a personalized GeoNetwork Template with the consideration of the logo included to this proposal and its colors. The ba

What is actionform, An ActionForm is a JavaBean that extends org.apache.str...

An ActionForm is a JavaBean that extends org.apache.struts.action.ActionForm.  ActionForm handles the session state for web application and the ActionForm object is automatically p

Java Login/Register Web CMS, I need help setting up and fleshing out a basi...

I need help setting up and fleshing out a basic outline/structure for a basic Java web app using an MVC pattern

What is constructor, What is Constructor? A constructor is used to init...

What is Constructor? A constructor is used to initialize a newly created object. It's called just after memory is allocated for the object. It can be used to initial

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.

What is a multicast delegate, What is a multicast delegate? Every deleg...

What is a multicast delegate? Every delegate object holds reference to a single method. Though, it is possible for a delegate object to hold references of and invoke multiple m

Streaming and decorator construction in java i/o, Java output and input is ...

Java output and input is described in terms of an abstract concept named a " stream ", which is a sequence of data. There are 2 types of streams. 1.      Byte streams (8 bit

How to use dispatchaction, To use the DispatchAction, follow these steps: ...

To use the DispatchAction, follow these steps: ? Make a class that extends DispatchAction (instead of Action) ? In a new class, add a method for each function you need to per

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