Basic Oops concept

Basic OOP Concepts

The main Object-Oriented Programming (OOP) concepts are:

• Inheritance
• Polymorphism
• Encapsulation
• Abstraction

1. Inheritance

Inheritance is a concept where one class can acquire the properties and behaviors of another class. It helps reuse code and establish a relationship between classes.

In Java, there are two types of classes involved in inheritance:

• Parent class (also called Superclass or Base class) – the class whose properties are inherited.
• Child class (also called Subclass or Derived class) – the class that inherits properties from the parent.

A class which inherits the properties is known as Child Class whereas a class whose properties are inherited is known as Parent class.

👉Read more about Inheritance here.

Example :

class Parent {
    void show() {
        System.out.println("Parent class method");
    }
}

class Child extends Parent {
    void display() {
        System.out.println("Child class method");
    }
}

2. Polymorphism :

Polymorphism means “many forms.” It is the ability of a variable, method, or object to take on multiple forms.

In Java, polymorphism is of two types:

1. Compile-time polymorphism – achieved through method overloading.
2. Run-time polymorphism – achieved through method overriding.

👉Read more about Polymorphism here.

Example ;

class Parent {
    void show() {
        System.out.println("Parent class method");
    }
}

class Child extends Parent {
    void display() {
        System.out.println("Child class method");
    }
}

3. Encapsulation :

Encapsulation is the process of wrapping data and methods together as a single unit. It also involves hiding data to prevent unauthorized access or modification.

In Java, encapsulation is achieved by:

• Declaring variables as private.
• Providing public getter and setter methods to access and modify these variables

Example:

class Person {
    private String name;  // private variable
    
    public String getName() { return name; }
    public void setName(String name) { this.name = name; }
}  

👉Read more about Encapsulation here.

4. Abstraction :

Abstraction is the process of hiding implementation details and showing only the functionality.

In Java, abstraction is achieved using:

• Interface – provides 100% abstraction (all methods are abstract).
• Abstract class – provides 0–100% abstraction (can have both abstract and concrete methods).

Example ;

abstract class Vehicle {
    abstract void start(); // abstract method
}

interface Drivable {
    void drive(); // abstract method
}

👉Read more about Abstraction here.