DragonX Blog

Object-Oriented Programming: The Core Concepts

OOP isn’t just theory — it’s the backbone of maintainable software in Java, Python, and many other languages. Here are the four pillars that make OOP so powerful:

🧱 1. Encapsulation

Encapsulation means bundling data and the methods that operate on it into a single unit (class), and restricting direct access to some of the object's components.

// Java
class User {
  private String name;

  public User(String name) {
    this.name = name;
  }

  public String getName() {
    return name;
  }
}
      

# Python
class User:
    def __init__(self, name):
        self.__name = name  # private variable

    def get_name(self):
        return self.__name

🧬 2. Inheritance

Inheritance lets one class inherit the properties and methods of another. It's the backbone of code reuse.

// Java
class Animal {
  void speak() {
    System.out.println("I make noise.");
  }
}

class Dog extends Animal {
  void speak() {
    System.out.println("Bark!");
  }
}

# Python
class Animal:
    def speak(self):
        print("I make noise.")

class Dog(Animal):
    def speak(self):
        print("Bark!")

🎭 3. Polymorphism

Polymorphism allows methods to behave differently based on the object calling them.

// Java
Animal myDog = new Dog();
myDog.speak(); // Output: Bark!

# Python
animal = Dog()
animal.speak()  # Output: Bark!

🧠 4. Abstraction

Abstraction hides complex logic and shows only the relevant details.

// Java
abstract class Shape {
  abstract void draw();
}

class Circle extends Shape {
  void draw() {
    System.out.println("Drawing Circle");
  }
}

# Python
from abc import ABC, abstractmethod

class Shape(ABC):
    @abstractmethod
    def draw(self):
        pass

class Circle(Shape):
    def draw(self):
        print("Drawing Circle")

These four pillars — Encapsulation, Inheritance, Polymorphism, and Abstraction — are essential to writing scalable and reusable code. Once you master OOP, writing maintainable code becomes second nature.

Got questions about OOP or want to see how I use it in real projects? Hit me up!