Class Accessibility Guide

Make each class or member as inaccessible as possible.

Accessibility:

• private: code from the same class or nested classes.
• Package-private: private plus code from the same package.
• protected: package-private plus code from sub-classes.
• public: anywhere.

private and package-private are considered implementation whereas protected and public are considered exported API.

protected is rarely useful.

Package-private is useful for writing tests.