Encapsulation in Java Classes: Hiding Internal Details, Exposing Only Necessary Interfaces

This article introduces the core of Java encapsulation: hiding internal class details and only exposing necessary interfaces to ensure data security and logical rationality. Encapsulation is implemented through access modifiers: using `private` to hide attributes (such as a student's `name` and `age`), which cannot be directly modified from outside; exposing interfaces through `public` methods (such as `setName` and `setAge`), with logical validation added within the methods (e.g., age cannot be negative). By comparing a wrong example (directly exposing attributes leading to illegal modifications) with a correct implementation (private attributes + validated methods), encapsulation can prevent data chaos (e.g., maintaining age within a reasonable range), achieve modularization (separation of internal and external), and enhance maintainability (internal logic changes do not affect the outside). Encapsulation is a foundation of Java's object-oriented programming. By hiding details and exposing secure interfaces, it ensures code robustness and is a key factor in writing high-quality code.