Encapsulation: Encapsulation is the bundling of data and methods that operate on the data into a single unit, often a class. It restricts direct access to some components, enhancing security and modularity. Example: In a class Car, attributes like speed and fuel are kept private and accessed through public methods like getSpeed() or refuel(). Inheritance: Inheritance allows a class (child) to inherit attributes and methods from another class (parent), promoting code reusability and hierarchical relationships. Example: A class ElectricCar can inherit from a parent class Car and add specific methods like chargeBattery(). Polymorphism: Polymorphism allows objects of different classes to be treated as objects of a common super class. It also enables methods to have the same name but behave differently based on the object. Example: A method startEngine() could behave differently for Car and ElectricCar objects. Abstraction: Abstraction hides implementation details and exposes only essential features of an object. Abstract classes and interfaces are used to implement this principle. Example: An interface Vehicle may define methods like start() and stop() without specifying how they work.