Object oriented concepts with java

1. Object Oriented Concepts With
JAVA
Mehta Ishani
2nd M.E.(C.S.E)

2. Why OOP?
• Traditional Procedural-Oriented languages
– difficult to copy a function from one program and
reuse in another program because the the
function is reference the headers, global variables
and other functions.
(i.e. not well-encapsulated
as a self-contained reusable unit.)
– not suitable of high-level
abstraction for solving
real life problems.

3. Why OOP?
• Object-oriented programming (OOP)
languages
– class, which encapsulates both the static
attributes and dynamic behaviors (i.e. well-
encapsulated, easier to reuse)
– permit higher level of
abstraction for solving
real-life problems

4. Benefits of OOP
• Ease in software design
• Ease in software maintenance
• Reusable software

5. What is JAVA?
• programming language expressly designed for
use in the distributed environment of the
Internet
• Simple, Secure, Robust, Complete Object
Oriented and Platform Independent High level
Language.
• It is portable and Multi-thread technology
gives High performance.

6. JAVA
Hardware Platform
Java Platform
Software (OS) Platform
Operates and
Controls H/W
Environment
for Java
Development
JVM API

7. JAVA
How it Works:

8. JAVA
Java
Program
Virtual
Machine
Source code Bytecode
Java Compiler
Process of Compilation:
Java
Interpreter
Virtual
Machine
Real MachineBytecode

9. Object
• real word entity that has state and behavior
• contains data (instance variables)
representing its state, and instance methods,
which are the things it can do.
• instance of a class

10. Class
• Collection of objects
• template, blueprint or contract that defines
what an object’s data fields and methods will
be.

11. Abstraction
• Hiding internal details and showing
functionality
• In java, we use abstract class and interface to
achieve abstraction.

12. Encapsulation
• Binding (or wrapping) code and data together
into a single unit
• A java class
• Java bean

13. Inheritance
• When one object acquires all the properties
and behaviors of parent object
• provides code reusability.
• Used to achieve runtime polymorphism.

14. Inheritance
A
B
C
A B
C
A-1
A-2
B-1
B-2
AB
Multi-level Inheritance Multiple Inheritance
Multiple Multi-level Inheritance
Types of Inheritance:

15. Ploymorphism
• "Poly" means "many" and "morph" means
"form".
• When one task is performed by different
ways

16. Polymorphism
• same word or symbol to be interpreted
correctly in different situations based on the
context
• There are two types of polymorphism :
1.Compile-time polymorphism (Method
Overloading/Static)
2.Runtime Polymorphism (Method
Overriding/Dynamic)

17. Ploymorphism
Method Overloading:
having multiple methods with same name but
with different signature (number, type and
order of parameters).
Method Overriding:
When a subclass contains a method with the same
name and signature as in the super class then it is
called as method overriding.

18. Summery
• An object is an instance of a class.
• Using abstraction one can simulate real world objects.
• Abstraction provides advantage of code reuse
• Abstraction enables program open for extension
• Encapsulation provides the security that keeps data
and methods safe from inadvertent changes.
• Inheritance is parent-child relationship of class which is
mainly used for code reusability.
• Polymorphism definition is that Poly means many and
morphos means forms.