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

Describe what is meant by a constructor in java, Question: (a) Describe...

Question: (a) Describe what is meant by a ‘constructor' in Java. Use a simple example to illustrate your answer. (b) Differentiate between a class method and an instance me

Create child processes, Using Fork() and Exec() or Clone(), create four ch...

Using Fork() and Exec() or Clone(), create four child processes. Load the same "Hello" program in each process after creation. This program should behave differently in each pro

String, in java string is a

in java string is a

What is the string concatenation, What is the String Concatenation + Op...

What is the String Concatenation + Operator is employed to concatenate strings - System.out.pritln ("Hello" + "World") will print Hello World on console String concatenat

What is a java applet, Question 1: (a) What are the disadvantages of u...

Question 1: (a) What are the disadvantages of using HTML Frames in your web pages? (b) Give five examples of controls used inside HTML forms and the situation in which the

Confidentiality and privacy - security, The confidentiality and privacy may...

The confidentiality and privacy may be accomplished through encryption. Encryption may be: Private-key or symmetric: This is based on a single key. This needs the sender and the

Statements and operators, Operator Functionality E x...

Operator Functionality E x ample/Explanation = Sets one value equal to another counter=0  Sets the counter to equivale

Difference between object declaration and object creation, Question: (a...

Question: (a) (i) Describe the purpose of comments when writing programs in Java. (ii) Name the types of comments available and illustrate with simple examples. (b) (i)

What are the design goals of java, What are the Design Goals of Java Ma...

What are the Design Goals of Java Massive growth of the Internet and World-Wide Web leads us to a completely new way of looking at development of software which can run on diff

Write a note on random access files, Question 1 What are the different typ...

Question 1 What are the different types of data types in java? Question 2 Write a note on Operator Precedence Question 3 Write a note on Random access files

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