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?

Function and array in java script, Specifications 1. readNumberOfEntri...

Specifications 1. readNumberOfEntries → This function will ask the user for a value greater than or equal to two. The function will keep asking values as long as the user prov

Difference between ejb 2.0and ejb 1.1, EJB 2.0 has the additional advantage...

EJB 2.0 has the additional advantages over the EJB 1.1 given below 1. Local interfaces : These are beans that can be needed locally, that means by the same Java Virtual Machi

What is actionmapping, Action mapping having all the deployment information...

Action mapping having all the deployment information for a particular Action bean. This class is to verify where the results of the Action will be sent once its processing is done.

For in statement, It is a distinct type of loop, used to iterate through th...

It is a distinct type of loop, used to iterate through the properties of an object or the elements of an array. For instance assume the following statement that loops through th

Moving test, After refactor the main class to become abstract class, I want...

After refactor the main class to become abstract class, I want to move test method from tset clas of main class to subclass, how to do that?

Need java assignment for course, Need Java Assignment for course Project...

Need Java Assignment for course Project Description: I want to get an assignment done. Involves building on a minesweeper game written in Java. You subsequent code is to be u

Batch file, how to create batch files of java program

how to create batch files of java program

Developing a prototype system in php and javascript, General Overview A...

General Overview A number of organisations are using micro-blogging as a cost-effective way of communicating with customers, building online communities and releasing informati

Coarse grained soa, Coarse Grained SOA : Services are also could be coa...

Coarse Grained SOA : Services are also could be coarse grained. E.g:   You may have a purchase element with individual functions to make a purchase order, add line items, and a

What is the use of throws keyword, What is the use of throws keyword ? ...

What is the use of throws keyword ? Rather than explicitly catching an exception you can declare in which your method throws the exception. This passes the repsonsibility to h

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