encapsulation

What problem does it solve?

Encapsulation helps maintain invariants by preventing external access to internal state and by routing mutations through controlled methods.

Core Features & Use Cases

• Hides internal data via private fields and exposes behavior through methods.
• Prevents invariants from being violated by external callers and supports safe evolution.
• Recommends getters/setters with validation and returns copies for collections to avoid aliasing.

Quick Start

Start by identifying public mutable state in a class, replace it with private fields, add public methods to mutate state with validation, and ensure callers use these methods rather than directly changing fields.