Introduction to OOP using Java
Saugata BoseIntroduction to OOP using Java
Different Programming Paradigms
Structured Programming
Object Oriented Programming
Java is an Object Oriented Language
ObjectsClassInheritanceEncapsulation
Example of a Java Codeclass Hello {public static void main(String[] args) {System.out.println(Hello World !!!); }}Hello.javaC:\javac Hello.java
C:\java HelloClass NameHello.class
OS/Hardwaremachine code
C source codehello.cgcchello.exe
Platform Dependent JVM
Java source codehello.javajavachello.class
OS/HardwarePlatform Independent
Objects Everywhere
NameHeightWeightEye ColormrBeanmyLamp
ColorHeight
IdentityProperties
Objects have state
Objects have behavior
Then what are objects .
How to interact with program?Service Provider
A class represents a concept, and an object represents the embodiment of a class
Objects and Classes
Bank AccountJohns Bank AccountBalance: $5,257Bills Bank AccountBalance: $1,245,069datamethods
Java Software
Person
Sakib
TamimTamimSakib: Say your nameclass Person{String askName(Person obj){System.out.println("My name is "+obj.toString());}}
class Main{public static void main(String[] args){Person shakib=new Person();Person tamim=new Person();shakib.askName(tamim);}}
Inheritance
Class Hierarchy
Generalization and Specialization
Encapsulation
Separation Why Java then?ModularityInformation Hiding class A{ int noOneCanSeeMe=5; int display(){System.out.println("Anyone can see me");}}Access Modifierspublicprivatepublic
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