Topic 13. The Java module system, the Maven and Gradle build systems, unit testing with JUnit

Goal: learn to separate modules, reproduce builds through the Wrapper, and verify class contracts with JUnit tests.

Lecture contents

1. Classpath and JPMS modules — From separate files to a reproducible project · Classpath and JPMS · Example 1. Two converter modules
2. Building with Maven — Maven: coordinates and lifecycle · Example 2. A Maven project for a loan calculator
3. The same project in Gradle — Example 3. The same code in Gradle
4. Testing with JUnit — JUnit: verifying behavior · Example 4. A parameterized validator · IDE, reports, and coverage · Common problems

Practice and review

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