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Example: A TV remote controls the TV by sending signals when you press buttons. However, you do
not need to understand how these signals are generated or how the TV processes them. The internal
circuitry and the way the buttons are wired are hidden from you. You only interact with the remote
by pressing the buttons provided.

Abstraction: Abstraction is the process of simplifying complex reality by modelling classes
appropriate to the problem. It focuses on exposing only the essential features and behaviours of an
object while hiding the internal details. The goal is to reduce complexity and allow the programmer

to focus on interacting with the object rather than worrying about how it works internally.
Example: When you drive a car, you interact with the steering wheel, pedals and gear shift. You
don’t need to know how the fuel injection system works, how the engine converts fuel into motion
or how the braking system operates. All those details are abstracted away so that you can drive the
car without understanding its internal mechanics.

Inheritance: Inheritance is a mechanism where a new class (called a subclass or derived class)
is created from an existing class (called a superclass or base class). The new class inherits all the

features (attributes and methods) of the base class and can also have additional features of its own.
This allows for code reuse and the creation of a hierarchy of classes.
Example: The Vehicle is a general category for all vehicles with common features like brand, model,
speed and essential functions (starting, stopping, accelerating). Specific types of vehicles—bikes,
cars, buses and trucks—inherit these basic features from Vehicle. Each type then adds its own unique
attributes, such as handlebars for bikes, doors and trunks for cars, large seating for buses and cargo

areas for trucks.

Vehicle

Bikes Cars Buses Trucks

Polymorphism: Polymorphism allows objects of different classes to be treated as objects of a

common superclass. In Object-Oriented Programming , polymorphism allows objects to be treated
as instances of their parent class rather than their actual class. This means that a single function or
method can operate on different types of objects, making the code more flexible and reusable.

Example: As a family car, it’s equipped with extra seats and space for luggage, making it suitable
for personal trips. When used as a taxi, it features a fare meter and a taxi sign for transporting
passengers. As a pool car for students, it includes extra safety seats and a schedule to manage
shared transportation. Despite these different uses, the car remains fundamentally the same,
demonstrating how one object can fulfil multiple roles.

Java Programming 111