This content originally appeared on DEV Community and was authored by Manasi Patil
The four pillars of Object-Oriented Programming (OOP) are fundamental principles that enable developers to build organized, reusable, and scalable software. Here’s an in-depth explanation of each pillar:
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- Encapsulation** Definition: Encapsulation is the technique of bundling data (variables) and methods (functions) that operate on that data into a single unit or class. It also restricts direct access to some of the object’s components, which means that object’s internal state is hidden from the outside.
Why It’s Important:
It protects the integrity of data by preventing outside interference and misuse. It is achieved in Java through access modifiers (private, protected, public) and getter/setter methods.
Real-World Example:
Think of a capsule or medicine bottle where the contents are hidden and only the necessary information (like dosage) is exposed.
2. Inheritance
Definition:
Inheritance allows a new class (child/subclass) to inherit fields and methods from an existing class (parent/superclass). This supports code reusability and establishes a natural hierarchy.
Why It’s Important:
It helps reduce redundancy, promotes extensibility, and allows polymorphic behavior.
Real-World Example:
A “Car” class can inherit from a “Vehicle” class, gaining all its properties while adding its own unique features.
3. Polymorphism
Definition:
Polymorphism means “many forms.” It allows objects of different classes related by inheritance to be treated as objects of a common superclass. The same method can perform different behaviors based on the object that it is acting upon.
Types:
Compile-time (Method Overloading): Same method name with different parameters.
Runtime (Method Overriding): Subclass provides a specific implementation of a method defined in superclass.
Why It’s Important:
Polymorphism enables flexibility and scalability, allowing one interface to be used for a general class of actions.
Real-World Example:
A “draw()” method might draw different shapes like circles, squares, or triangles, depending on the object.
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- Abstraction** Definition: Abstraction is the concept of hiding complex implementation details and showing only the necessary features to the user. It focuses on what an object does instead of how it does it.
Why It’s Important:
It reduces complexity by hiding irrelevant details and allows focusing only on essential characteristics.
Real-World Example:
Using a TV remote control—you press buttons without needing to understand the internal workings of the electronics.
This content originally appeared on DEV Community and was authored by Manasi Patil