Topic 5. Classes and objects: fields, methods, constructors, encapsulation, and packages

Goal: design validated classes with private state, constructors, and methods; use packages, static members, and defensive copies.

Lecture contents

1. Classes, fields, and constructors — A class combines data and rules · Fields, references, and memory · Constructors and this
2. Initialization, access, and static members — Initialization order and modern constructors · Access and encapsulation · Static members and factories
3. Packages, classpath, and JAR — Packages and paths · Compilation, classpath, and JAR
4. Utility classes and code quality — Utility classes and static imports · Javadoc, IDE, and quality checks

Practice and review

• Practice — 3 worked examples with complete code
• Tasks — 30 variants, each with tasks at three difficulty levels
• Summary — conclusions and self-check questions