R2021 - SEMESTER III CS3391 OOP UNIT - I TOPIC -3: FEATURES OF OBJECT ORIENTED PROGRAMMING

1. P1WU
UNIT – I: INTRODUCTION TO OOP AND JAVA
TOPIC -3: FEATURES OF OBJECT ORIENTED
PROGRAMMING
AALIM MUHAMMED SALEGH COLLEGE OF ENGINEERING
DEPARTMENT OF INFORMATION TECHNOLOGY
SEMESTER – III
UNIT I INTRODUCTION TO OOP AND JAVA

2. UNIT I INTRODUCTION TO OOP AND JAVA
1. Overview of OOP
2. Object oriented
programming paradigms
3. Features of Object
Oriented
Programming
4. Java Buzzwords
5. Overview of Java – Data Types,
Variables and Arrays
6.Operators
7.Control Statements
8.Defining classes in Java
9.Constructors
10.Methods
11. Access specifiers
12.Static members
13. JavaDoc comments
AALIM MUHAMMED SALEGH COLLEGE OF ENGINEERING
DEPARTMENT OF INFORMATION TECHNOLOGY
SEMESTER – III
UNIT I INTRODUCTION TO OOP AND JAVA

3. FEATURES OF OBJECT ORIENTED PROGRAMMING
AALIM MUHAMMED SALEGH COLLEGE OF ENGINEERING
DEPARTMENT OF INFORMATION TECHNOLOGY
SEMESTER – III
UNIT I INTRODUCTION TO OOP AND JAVA

4. FEATURES OF OBJECT ORIENTED PROGRAMMING
• The Object–Oriented Programming principles are defended with
concepts of Object–Oriented Systems (OOPS)
1. Object
2. Class
3. Encapsulation
4. Abstraction
5. Polymorphism
6. Inheritance
AALIM MUHAMMED SALEGH COLLEGE OF ENGINEERING
DEPARTMENT OF INFORMATION TECHNOLOGY
SEMESTER – III
UNIT I INTRODUCTION TO OOP AND JAVA

5. a) Object
• An object is a real-world element in an object–oriented
environment that may have a physical or a conceptual existence.
Each object has −
• Identity that distinguishes it from other objects in the system.
• State that determines characteristic properties of an object as well
as values of properties that the object holds.
• Behavior that represents externally visible activities performed by
an object in terms of changes in its state.
AALIM MUHAMMED SALEGH COLLEGE OF ENGINEERING
DEPARTMENT OF INFORMATION TECHNOLOGY
SEMESTER – III
UNIT I INTRODUCTION TO OOP AND JAVA

6. a) Object
• Objects can be modeled according to the needs of the application.
• An object may have a physical existence, like a customer, a car, etc.;
or an intangible conceptual existence, like a project, a process, etc.
• Object means a real word entity such as pen, chair, table etc.
• Any entity that has state and behavior is known as an object.
AALIM MUHAMMED SALEGH COLLEGE OF ENGINEERING
DEPARTMENT OF INFORMATION TECHNOLOGY
SEMESTER – III
UNIT I INTRODUCTION TO OOP AND JAVA

7. a) Object
• Object can be defined as an instance of a class.
• An object contains an address and takes up some space in
memory.
• Objects can communicate without knowing details of :
• each other's data or code,
• the only necessary thing is that the type of message accepted and
• type of response returned by the objects.
AALIM MUHAMMED SALEGH COLLEGE OF ENGINEERING
DEPARTMENT OF INFORMATION TECHNOLOGY
SEMESTER – III
UNIT I INTRODUCTION TO OOP AND JAVA

8. a) Object
• An object has three characteristics:
• state: represents data (value) of an object.
• behavior: represents the behavior (functionality) of an
object such as deposit, withdraw etc.
• identity: Object identity is typically implemented via a
unique ID.
• The value of the ID is not visible to the external user. But, it
is used internally by the JVM to identify each object
uniquely.
AALIM MUHAMMED SALEGH COLLEGE OF ENGINEERING
DEPARTMENT OF INFORMATION TECHNOLOGY
SEMESTER – III
UNIT I INTRODUCTION TO OOP AND JAVA

9. b) Class
• A class represents a collection of objects having same
characteristic properties that exhibit common behavior.
• It gives the blueprint or the description of the objects that can be
created from it.
• Creation of an object as a member of a class is called instantiation.
• Collection of objects is called class.
• It is a logical entity.
AALIM MUHAMMED SALEGH COLLEGE OF ENGINEERING
DEPARTMENT OF INFORMATION TECHNOLOGY
SEMESTER – III
UNIT I INTRODUCTION TO OOP AND JAVA

10. b) Class
• A class can also be defined as a blueprint from which you can
create an individual object.
• A class consists of Data members and methods.
• The primary purpose of a class is to hold data/information.
• The member functions determine the behavior of the class,
• i.e. provide a definition for supporting various operations on data held in
the form of an object.Class doesn’t store any space.
AALIM MUHAMMED SALEGH COLLEGE OF ENGINEERING
DEPARTMENT OF INFORMATION TECHNOLOGY
SEMESTER – III
UNIT I INTRODUCTION TO OOP AND JAVA

11. b) Class
• Thus, an object is an instance of a class.
• The constituents of a class are −
1. A set of attributes for the objects that are to be instantiated
from the class.
• Generally, different objects of a class have some difference in the values of the
attributes.
• Attributes are often referred as class data.
2. A set of operations that portray the behavior of the objects of
the class. Operations are also referred as functions or
methods
AALIM MUHAMMED SALEGH COLLEGE OF ENGINEERING
DEPARTMENT OF INFORMATION TECHNOLOGY
SEMESTER – III
UNIT I INTRODUCTION TO OOP AND JAVA

12. b) Class
• Example
• Let us consider a simple class, Circle, that represents the
geometrical figure circle in a two–dimensional space.
• The attributes of this class can be identified as follows −
• x–coord, to denote x–coordinate of the center
• y–coord, to denote y–coordinate of the center
• a, to denote the radius of the circle
AALIM MUHAMMED SALEGH COLLEGE OF ENGINEERING
DEPARTMENT OF INFORMATION TECHNOLOGY
SEMESTER – III
UNIT I INTRODUCTION TO OOP AND JAVA

13. b) Class
• Some of its operations can be defined as follows −
1. findArea(), a method to calculate area
2. findCircumference(), a method to calculate circumference
3. scale(), a method to increase or decrease the radius
AALIM MUHAMMED SALEGH COLLEGE OF ENGINEERING
DEPARTMENT OF INFORMATION TECHNOLOGY
SEMESTER – III
UNIT I INTRODUCTION TO OOP AND JAVA

14. c) Encapsulation
• Encapsulation is
• the process of binding both attributes and methods together within a
class.
• Encapsulation in java is a process of wrapping code and data
together into a single unit,
• for example capsule i.e. mixed of several medicines.
• Through encapsulation, the internal details of a class can be
hidden from outside.
AALIM MUHAMMED SALEGH COLLEGE OF ENGINEERING
DEPARTMENT OF INFORMATION TECHNOLOGY
SEMESTER – III
UNIT I INTRODUCTION TO OOP AND JAVA

15. c) Encapsulation
• It permits
• the elements of the class
to be accessed from
outside only through the
interface provided by the
class.
• A java class is the
example of
encapsulation.
AALIM MUHAMMED SALEGH COLLEGE OF ENGINEERING
DEPARTMENT OF INFORMATION TECHNOLOGY
SEMESTER – III
UNIT I INTRODUCTION TO OOP AND JAVA

16. d) Abstraction
• Abstraction is
• a process of hiding the implementation details and showing
only functionality to the user.
• Example:
• phone call, we don't know the internal processing.
• In java, we use abstract class and interface to achieve
abstraction.
AALIM MUHAMMED SALEGH COLLEGE OF ENGINEERING
DEPARTMENT OF INFORMATION TECHNOLOGY
SEMESTER – III
UNIT I INTRODUCTION TO OOP AND JAVA

17. e) Polymorphism
• Polymorphism is originally a Greek word that means the ability to
take multiple forms.
• Ploy  Many
• Morphism  Form
• In object-oriented paradigm, polymorphism implies:
• using operations in different ways, depending upon the
instances they are operating upon.
AALIM MUHAMMED SALEGH COLLEGE OF ENGINEERING
DEPARTMENT OF INFORMATION TECHNOLOGY
SEMESTER – III
UNIT I INTRODUCTION TO OOP AND JAVA

18. e) Polymorphism
• Polymorphism allows
• objects with different internal structures to have a common
external interface.
• Use:
• Polymorphism is particularly effective while implementing
inheritance.
AALIM MUHAMMED SALEGH COLLEGE OF ENGINEERING
DEPARTMENT OF INFORMATION TECHNOLOGY
SEMESTER – III
UNIT I INTRODUCTION TO OOP AND JAVA

19. e) Polymorphism : Example
• Let us consider two classes,
• Circle class
• Square class
• Look for Poly- method called findArea().
• Here, Circle and Square, each with a method findArea().
AALIM MUHAMMED SALEGH COLLEGE OF ENGINEERING
DEPARTMENT OF INFORMATION TECHNOLOGY
SEMESTER – III
UNIT I INTRODUCTION TO OOP AND JAVA

20. e) Polymorphism : Example
• Though the name and purpose of the methods in the
classes are same, the internal implementation,
• i.e., the procedure of calculating an area is different for each
class.
• When an object of class Circle invokes its findArea()
method,
• the operation finds the area of the circle without any conflict
with the findArea() method of the Square class.
AALIM MUHAMMED SALEGH COLLEGE OF ENGINEERING
DEPARTMENT OF INFORMATION TECHNOLOGY
SEMESTER – III
UNIT I INTRODUCTION TO OOP AND JAVA

21. e) Polymorphism : Example
• When one task is performed
by different ways i.e. known
as polymorphism.
• For example: to convince the
customer differently, to draw
something e.g. shape or
rectangle etc.
AALIM MUHAMMED SALEGH COLLEGE OF ENGINEERING
DEPARTMENT OF INFORMATION TECHNOLOGY
SEMESTER – III
UNIT I INTRODUCTION TO OOP AND JAVA

22. Types of Polymorphism
• Polymorphism is classified into two ways:
1) Method Overloading(Compile time Polymorphism)
2) Method Overriding(Run time Polymorphism)
AALIM MUHAMMED SALEGH COLLEGE OF ENGINEERING
DEPARTMENT OF INFORMATION TECHNOLOGY
SEMESTER – III
UNIT I INTRODUCTION TO OOP AND JAVA

23. 1) Method Overloading(Compile time Polymorphism)
• Method Overloading is a feature that allows
• a class to have two or more methods having the same name
but the arguments passed to the methods are different.
• Compile time polymorphism refers to
• a process in which a call to an overloaded method is resolved at
compile time rather than at run time.
AALIM MUHAMMED SALEGH COLLEGE OF ENGINEERING
DEPARTMENT OF INFORMATION TECHNOLOGY
SEMESTER – III
UNIT I INTRODUCTION TO OOP AND JAVA

24. 2) Method Overriding(Run time Polymorphism)
• If subclass (child class) has the same method as declared
in the parent class, it is known as method overriding in
java.
• If subclass provides the specific implementation of the
method that has been provided by one of its parent class,
it is known as method overriding.
AALIM MUHAMMED SALEGH COLLEGE OF ENGINEERING
DEPARTMENT OF INFORMATION TECHNOLOGY
SEMESTER – III
UNIT I INTRODUCTION TO OOP AND JAVA

25. f) Inheritance
• It is a mechanism that permits
• new classes to be created out of existing classes by extending and refining
its capabilities.
Scenario: Having / implementing more than one class
• The existing classes are called the base classes/parent
classes/super-classes, and
• the new classes are called the derived classes/child
classes/subclasses.
AALIM MUHAMMED SALEGH COLLEGE OF ENGINEERING
DEPARTMENT OF INFORMATION TECHNOLOGY
SEMESTER – III
UNIT I INTRODUCTION TO OOP AND JAVA

26. f) Inheritance
• Facility from inherit property:
• The subclass can inherit or derive the attributes and methods of
the super-class (es) provided that the super-class allows so.
• Besides, the subclass may add its own attributes and methods and
may modify any of the super-class methods. Inheritance defines a
“is – a” relationship.
AALIM MUHAMMED SALEGH COLLEGE OF ENGINEERING
DEPARTMENT OF INFORMATION TECHNOLOGY
SEMESTER – III
UNIT I INTRODUCTION TO OOP AND JAVA

27. f) Inheritance
• What is an Inheritance?
• Inheritance can be defined as the procedure or mechanism of
acquiring all the properties and behavior of one class to another,
i.e., acquiring the properties and behavior of child class from the
parent class.
AALIM MUHAMMED SALEGH COLLEGE OF ENGINEERING
DEPARTMENT OF INFORMATION TECHNOLOGY
SEMESTER – III
UNIT I INTRODUCTION TO OOP AND JAVA

28. f) Inheritance
• When one object acquires all the properties and behaviours of
another object, it is known as inheritance.
• It provides code reusability and establishes relationships between
different classes.
• A class which inherits the properties is known as Child Class(sub-
class or derived class) whereas a class whose properties are
inherited is known as Parent class(super-class or base class).
AALIM MUHAMMED SALEGH COLLEGE OF ENGINEERING
DEPARTMENT OF INFORMATION TECHNOLOGY
SEMESTER – III
UNIT I INTRODUCTION TO OOP AND JAVA

29. f) Inheritance
• Types of inheritance
• Types of inheritance in java:
1. single,
2. multilevel and
3. hierarchical inheritance.
• Multiple and hybrid inheritance is supported through interface
only.
AALIM MUHAMMED SALEGH COLLEGE OF ENGINEERING
DEPARTMENT OF INFORMATION TECHNOLOGY
SEMESTER – III
UNIT I INTRODUCTION TO OOP AND JAVA

30. f) Inheritance
• Example
• From a class Mammal, a number of classes can be derived such as
Human, Cat, Dog, Cow, etc. Humans, cats, dogs, and cows all have
the distinct characteristics of mammals.
• In addition, each has its own particular characteristics.
• It can be said that a cow “is – a” mammal.
AALIM MUHAMMED SALEGH COLLEGE OF ENGINEERING
DEPARTMENT OF INFORMATION TECHNOLOGY
SEMESTER – III
UNIT I INTRODUCTION TO OOP AND JAVA

31. Features of object oriented programming paradigm
1. Programs are divided into simple elements referred to as object
2. Focus is on properties and functions rather than procedure.
3. Data is hidden from external functions.
4. Functions operate on the properties of an object.
5. Objects may communicate with each other through a function
called messaging.
6. Follow the bottom-up approach in oop design
AALIM MUHAMMED SALEGH COLLEGE OF ENGINEERING
DEPARTMENT OF INFORMATION TECHNOLOGY
SEMESTER – III
UNIT I INTRODUCTION TO OOP AND JAVA

32. THANK YOU
AALIM MUHAMMED SALEGH COLLEGE OF ENGINEERING
DEPARTMENT OF INFORMATION TECHNOLOGY
SEMESTER – III
UNIT I INTRODUCTION TO OOP AND JAVA

33. AALIM MUHAMMED SALEGH COLLEGE OF ENGINEERING
DEPARTMENT OF INFORMATION TECHNOLOGY
SEMESTER – III
UNIT I INTRODUCTION TO OOP AND JAVA