🎯 Object-Oriented Programming (OOP) Concepts in Java
🚀 Overview
Object-Oriented Programming (OOP) in Java allows developers to create reusable, modular, and scalable code by structuring it around objects and classes.
🌟 Core Concepts
1. 🎭 Class and Object
- Class: A blueprint for creating objects.
- Object: An instance of a class.
☕JAVA
// Class definition
public class Car {
String brand;
String model;
// Constructor
public Car(String brand, String model) {
this.brand = brand;
this.model = model;
}
// Method
public void displayDetails() {
System.out.println("Brand: " + brand + ", Model: " + model);
}
}
// Creating an object
Car myCar = new Car("Tesla", "Model S");
myCar.displayDetails();
2. 🔒 Encapsulation
- Restricts access to certain parts of an object.
- Uses private fields with getter and setter methods.
☕JAVA
public class BankAccount {
private double balance;
// Constructor
public BankAccount(double balance) {
this.balance = balance;
}
// Getter method
public double getBalance() {
return balance;
}
// Setter method
public void deposit(double amount) {
balance += amount;
}
}
3. 🧬 Inheritance
- Enables one class (child) to inherit fields and methods from another class (parent).
☕JAVA
// Parent class
public class Vehicle {
public void startEngine() {
System.out.println("Engine started!");
}
}
// Child class
public class Car extends Vehicle {
public void playMusic() {
System.out.println("Playing music!");
}
}
// Usage
Car myCar = new Car();
myCar.startEngine();
myCar.playMusic();
4. ⚡ Polymorphism
- Allows methods to take different forms (overloading and overriding).
☕JAVA
// Overloading
public class Calculator {
public int add(int a, int b) {
return a + b;
}
public double add(double a, double b) {
return a + b;
}
}
// Overriding
class Animal {
public void sound() {
System.out.println("Animal makes a sound");
}
}
class Dog extends Animal {
@Override
public void sound() {
System.out.println("Dog barks");
}
}
5. 🏗️ Abstraction
- Hides implementation details and exposes only essential features.
☕JAVA
abstract class Animal {
abstract void sound(); // Abstract method
public void sleep() { // Concrete method
System.out.println("Sleeping...");
}
}
class Cat extends Animal {
@Override
void sound() {
System.out.println("Cat meows");
}
}
// Usage
Animal cat = new Cat();
cat.sound();
cat.sleep();
📌 Key Benefits of OOP
- 📦 Reusability: Reuse code through inheritance.
- 🔍 Data Security: Encapsulation hides sensitive data.
- 🚀 Scalability: Easily extend features using polymorphism.
- 🛠️ Maintainability: Abstraction simplifies code updates.