OOPs Concepts

OOPS (Object Oriented Programming Structures)

What is Abstraction?

• Abstraction is the concept of hiding irrelevant (not related to the task) details.In other words, make complex/typical system simple by hiding the unnecessary detail from the user and make it user-friendly.
• The abstract class specifies what functionality is provided but not how that functionality is provided.
• For example, one does not want to understand how the engine works. Similarly one does not have to understand the internal implementation of the software objects.
• Abstraction provides a way to hide the less essential properties so as to reduce complexity and increase efficiency.
• Abstraction Example: Engine and Driver.

What is Encapsulation?

• Encapsulation is the technique of making the fields in a class private and providing access to the fields through public methods. Encapsulation is also called as data hiding.
• The benefits of encapsulation:
• The capability of changing\updating your code without disturbing the code of others
• Encapsulation gives maintainability, flexibility, and extensibility to our code.
• The fields of a class can be made read-only or write-only.
• A class can have total control over of what is stored in its fields.
• A class is able to change the data type, and users of the class never need to the changes of their code.

 

What is Polymorphism?

• Polymorphism is an important Object Oriented concept and widely used in all Object Oriented Programming Language.
• Polymorphism word comes from ancient Greek where poly means many.Polymorphism means many forms.
• Polymorphism in Java means the same object behave differently in a different place.
• For e.g Lady is one of the example polymorphism.Same Lady object will behave differently when she is sister, wife and mother.
• Example:-

package in.java4all.polymorphism;
public class AccountClass {
public String accountopen(){
return "Account Opened";
}
}
class SavingAccountClass extends AccountClass{
public String accountopen(){
return "Saving Account Opened";
}
}
class CurrentAccountClass extends AccountClass{
public String accountopen(){
return "Current Account Opened";
}
}

   NOTE:-

• There are two kinds of polymorphism

• Compile time polymorphism (static binding or method overloading)

• Runtime polymorphism (dynamic binding or method overriding)

What is Inheritance in Java?

• Inheritance in Java is an Object oriented or OOPS concepts, which is same as real-world Inheritance behaviour,
• Inheritance allows code reuse in Java. Along with Abstraction, Polymorphism and Encapsulation, Inheritance forms the basis of Object-oriented programming.
• Inheritance is implemented using extends keyword in Java and When one Class extends another Class it inherits all public members including fields and methods.
• Parent class called as Superclass and child class as Subclass in Java programming language.
• The class which extends another class becomes Child of the class it extends(Parent Class) and inherit all its behaviour which is not private.
• There are a lot of example of Inheritance in Object-oriented world e.g. Dog inherit properties of Animal, Car inherits properties of Vehicle etc.
• In Java programming language, Child class inherit its Parent class's property and behaviour like the real world where child inherits the property of parent.
• EXAMPLE:-

public  class Vehicle {}
public  class FourWheeler extends Vehicle {}
public  class Car extends FourWheeler{}
public  class BMW extends Car{}

• Both are in Java are two OOPs(Object Oriented Programming Structure) concepts but they are completely different to each other.
• Encapsulation:- It is a process of binding or we can say wrapping of the codes that operates on the data into a single entity. This keeps the data safe from outside users.
• Abstraction is the concept of hiding irrelevant/unnecessary details.In other words, make the complex/typical system simple by hiding the unnecessary detail from the user and make it user-friendly.