Encapsulation in Java

Encapsulation is a fundamental concept in Object-Oriented Programming (OOP) that involves bundling the data (attributes) and methods that operate on the data into a single unit, or class, and restricting access to some of the object’s components. This is typically achieved through the use of private variables, which are only accessible within the same class, and public methods, known as getters and setters, which are used to read and modify these variables.

Why Encapsulation Is Needed

  1. Data Hiding: Encapsulation allows sensitive data to be hidden from the users. By making the class variables private and providing public getter and setter methods, the internal state of an object is shielded from outside direct access, protecting the integrity of the object.
  2. Increased Flexibility and Maintainability: With encapsulation, the implementation details of a class can be changed at any point without affecting the classes that use it, as long as the interface remains the same. This makes the code more flexible and maintainable.
  3. Control over Data: Encapsulation provides control over the data by allowing validation to be performed within the setter methods. This ensures that only valid data is stored in the object.

Encapsulation with Validation Code Examples

Let’s illustrate encapsulation with a simple Person class, where we control the age of the person to ensure it’s always a positive integer.

Demonstrating Encapsulation with Validation


In this example, the Person class encapsulates the name and age attributes, providing public getter and setter methods to access and modify these properties. The setter method for age includes validation logic to ensure that only positive integers are accepted, demonstrating control over the data and protecting the integrity of the Person object.

This approach to encapsulation with validation not only ensures data integrity within an object but also enhances the security, flexibility, and maintainability of the code, making it a cornerstone of effective OOP design.

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