Phase 3 - Intermediate Engineering

Goal: Write production-quality Java. Master design patterns, testing discipline, and the tooling that professional projects use every day.

Module	Topic	Status
25	Design Patterns - creational, structural, behavioural	✅
26	Unit Testing - JUnit 5, Mockito, test design	✅
27	Integration Testing - Testcontainers, REST-assured	✅
28	Build Tools - Maven deep-dive, Gradle intro	✅
29	Logging & Observability - SLF4J, Logback, Micrometer	✅
30	Clean Code & Refactoring - SOLID, code smells, IDE tools	✅

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Table of contents

• Module 25 - Design Patterns
• Module 26 - Unit Testing
• Module 27 - Integration Testing
• Module 28 - Build Tools
• Module 29 - Logging & Observability
• Module 30 - Clean Code & Refactoring