Illustrate inheritance and composition?, JAVA Programming

Assignment Help:

The 'is a' relationship is used with inheritance and 'has a' relationship is used with composition. Both composition and inheritance allow you to perform sub-objects inside your new class. Two of the main techniques for code reuse are object composition and class inheritance.

378_Untitled.png

 

Inheritance is single-directional. For example man is a human. But human is not a man. Inheritance needs extends key word. Composition: is used when Man has an eye. It is incorrect to say man is an eye. Composition simply defines using instance variables that refer to other objects. The class man will have an instance variable, which refers to an eye object.

 

 Which one to favor, inheritance or composition? The guide is that inheritance could be only used when subclass 'is a' superclass.

1. Don't use inheritance just to get programming code reuse. If there is no 'is a' relationship then require composition for code reuse. Overuse of implementation inheritance will divide all the subclasses, if the superclass is changed.

 

2. Do not add inheritance just to get polymorphism. If there is no 'is a' relationship and all you need is polymorphism then use interface inheritance with composition, which provides you code reuse.

 


Related Discussions:- Illustrate inheritance and composition?

Want a page to store emails when click as save, Want a page to store emails...

Want a page to store emails when click as save, then pass along to another page with the emails in the URL Project Description: I have a page that populates with listing; the

What is an introduction in aop, An introduction permits the user to add new...

An introduction permits the user to add new methods or attributes to an existing class. This can then be explained to an existing class without having to change the structure of th

What is jms client, An application or procedure that produces and/or receiv...

An application or procedure that produces and/or receives messages.

What is externalizable interface, What is Externalizable interface? Ext...

What is Externalizable interface? Externalizable is an interface which have two methods readExternal and writeExternal. These methods give you a control over the serialization

Assignment 1, student are required to construct classes for circle,triangle...

student are required to construct classes for circle,triangle,trapezium and kite.

Explain instance variable, What will be the default values of all the eleme...

What will be the default values of all the elements of an array explained as an instance variable? If the array is an array of primitive types, then all the elements of the arr

What are the implicit objects in jsp, Implicit objects are formed by the we...

Implicit objects are formed by the web container and have information related to a particular request, page, or application. They are request, response, pageContext, session, appli

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