COMPUTER APPLICATIONS
Tutorial
on JAVA
Dheeraj Mehrotra
City Montessori School & Degree College
Lucknow (India)
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Concept of OOP
o OOP
stands
for
Object
Oriented
Programming. It is the latest trend in
programming languages supported by C++
and Java and has had the revolutionary
success in the race of OOP. The limitations
of the Procedure Oriented Programming
(POP) languages, have given place to the
development of the OOP.
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CLASSES & OBJECTS
Object :
An object is an identifiable entity with some characteristic and behaviour. o
Class :
A Class is a group of objects that share common properties and relationships.
The Objects are variables of type Class eg.
If animal has been defined as a Class, then the statement; o
animal dog;
will create an Object featuring dog belonging to the class animal.
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CORE CONCEPTS OF OOP
o The basic concepts of Object Oriented
Programming (OOP) are :
n Abstraction
n Encapsulation
n Inheritance
n Polymorphism
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Features of OOP
Abstraction refers to the act of representing essential features without including the background details or explanations. o
Encapsulation is an act of wrapping up of data and methods into a single unit (called class). It is one of the most fundamental concepts of the Object Oriented programming. The very insulation of the data from direct access by the program is termed as Data Hiding. Encapsulation, is hence, just a way to implement Abstraction.
Inheritance is the process by which objects of one class acquire the properties of objects of another class. This further provides an important extension to the idea of reusability. i.e. a particular programmer can make use of an existing class and without any further modifications, add additional features and capabilities to it, by deriving a new class from the existing one, through inheritance.
