Notes – Object Oriented Programming in Java

Java is known as a pure object-oriented programming language, meaning it is designed around the concept of objects and classes.

Let’s explore what this means in simple terms.

OOP is a programming style where real-world entities like person, car, bank account are represented as objects.
These objects contain data (fields/attributes) and behavior (methods/functions).

Example:

class Car {
    String color;
    void drive() {
        System.out.println("Car is moving");
    }
}

Concept	Description
Encapsulation	Wrapping data (variables) and code (methods) together in one unit, i.e., a class.
Inheritance	One class (child) can reuse the features of another class (parent).
Polymorphism	One function behaves differently in different scenarios.
Abstraction	Hiding internal details and showing only the essential features.

Everything in Java revolves around classes and objects.
Java uses OOP to structure code for better reusability, scalability, and maintenance.

Term	Description
Class	Blueprint of an object; defines properties and methods.
Object	Instance of a class; occupies memory.
Method	A function defined inside a class.
Constructor	Special method used to initialize objects.
Access Modifiers	Keywords like `public`, `private`, and `protected` to control visibility.

Class: Dog
Object: Your pet dog, Max
Data (fields): name = “Max”, breed = “Labrador”
Behavior (methods): bark(), sleep()

class Dog {
    String name;
    void bark() {
        System.out.println(name + " is barking");
    }
}

Java is object-oriented because:

It supports all core OOP principles (Encapsulation, Inheritance, Polymorphism, Abstraction).
Programs are structured using classes and objects.
It improves modularity, reusability, and real-world modeling in programming.