Encapsulation

Definition

Encapsulation is a core concept in object-oriented programming that bundles data and the methods that operate on that data within a single unit, restricting direct access from the outside. It protects the internal state of an object and only exposes a controlled interface through methods.

Where you hear it

- In code reviews when discussing data hiding and visibility modifiers. - During system design discussions about keeping internal class details private. - In software architecture interviews focusing on object-oriented principles.

Examples

• The bank account class hides the raw balance variable and provides a deposit method to safely update the funds.
• We use private fields in the user service to prevent other modules from modifying state directly.