How is object-oriented programming implemented in Java?

Object-oriented programming (OOP) in Java is implemented through core principles: encapsulation, inheritance, polymorphism, and abstraction.

• Classes and objects: A class is a template for creating objects, which are instances of the class.
• Encapsulation: Hiding data within a class using access modifiers (private, protected, public).
• Inheritance: Allows creating a new class based on an existing one, using the extends keyword.
• Polymorphism: The ability to use objects of different classes through a common interface or base class.
• Abstraction: Defining abstract classes and interfaces to describe common properties and behaviors.

Example:

public class Animal {
    public void sound() {
        System.out.println("Some sound");
    }
}

public class Dog extends Animal {
    @Override
    public void sound() {
        System.out.println("Bark");
    }
}

public class Main {
    public static void main(String[] args) {
        Animal myDog = new Dog();
        myDog.sound(); // Outputs "Bark"
    }
}