What are Encapsulation, Inheritance and Polymorphism?

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Encapsulation is the mechanism that binds together code and data it manipulates and keeps both safe from outside interference and misuse. Inheritance is the process by which one object acquires the properties of another object. Polymorphism is the feature that allows one interface to be used for general class actions.

In Java, Encapsulation, Inheritance, and Polymorphism are three fundamental concepts of object-oriented programming (OOP). Here’s a brief explanation of each:

  1. Encapsulation:
    • Definition: Encapsulation is the bundling of data (attributes) and methods (functions) that operate on the data into a single unit, often referred to as a class. It is a protective barrier that keeps the data safe within the object and prevents unauthorized access from outside the object.
    • Key Points:
      • Data hiding: Encapsulation allows hiding the implementation details and exposing only what is necessary.
      • Access modifiers (public, private, protected) are used to control access to the members of a class.
  2. Inheritance:
    • Definition: Inheritance is a mechanism that allows a new class (subclass or derived class) to inherit properties and behaviors (attributes and methods) from an existing class (superclass or base class). The subclass can then extend or override the inherited functionality.
    • Key Points:
      • Reusability: Inheritance promotes code reuse by allowing the reuse of existing class features in a new class.
      • “IS-A” relationship: The subclass is a specialized version of the superclass.
  3. Polymorphism:
    • Definition: Polymorphism allows objects of different types to be treated as objects of a common type. It enables a single interface to represent different underlying types or forms. There are two types of polymorphism: compile-time (method overloading) and runtime (method overriding).
    • Key Points:
      • Compile-time polymorphism: Achieved through method overloading, where multiple methods with the same name but different parameter lists can coexist in the same class.
      • Runtime polymorphism: Achieved through method overriding, where a subclass provides a specific implementation for a method that is already defined in its superclass.

In summary, encapsulation focuses on bundling data and methods together, inheritance enables the creation of new classes based on existing ones, and polymorphism allows objects to be treated as instances of their superclass, providing flexibility and extensibility in object-oriented designs.