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Challenge: Java Advanced Language Features - Using Sealed Interfaces and Records

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Path Info

Duration

14m

Last updated

Jun 24, 2025

Challenge

Use a Sealed Interface and Records
Interface Transaction is a sealed interface with two subclasses: Purchase and Refund.

Class TransactionService contains a method calculateNetAmount to calculate the net amount of a list of purchase and refund transactions.
Solution
```
You can find the solution to this exercise in the **CompletedExercise** directory in the filetree.
```
To run your methods, click the **Run** button in the bottom right of the terminal to run the code in `App.java`.

Author

Jesper de Jong

Jesper de Jong is an independent, experienced software developer and architect who designs and builds efficient, scalable, and high-quality server-side software for the JVM in Java and Scala. He loves the creativity of inventing and building software systems and loves to teach and share his knowledge with the software development community.

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