Classpath problems JPMS solves
On This Lesson 4 topics
This lesson is planned. The outline below lists the topics it will cover. The full lesson has not been published yet.
In this lesson
explain why the Java Platform Module System (JPMS) exists.
Planned topics
- The classpath is a flat list of JARs; any public class is reachable by anyone.
- Problems: missing dependencies found only at runtime, split packages, version conflicts, no real encapsulation.
- JPMS (Java 9) adds explicit dependencies and strong encapsulation.
- The JDK itself is modularized; internal packages are no longer open by default.
- Adoption in application backends is uneven.
Draft outline details
Demonstration
a diagram: classpath (one flat bag) vs modules (boxes with arrows).
Check your understanding
What does public mean without JPMS?
Show answer
Visible to everything on the classpath.
Practice
Apply this lesson with the module's lab, exercises and quiz.
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