Help! I Inherited Legacy Code – What Now?

We’re happy to announce our next CodeLab!
Join us for a hands-on workshop: “Help! I Inherited Legacy Code – What Now?”

What exactly is legacy code? Ask five developers and you’ll get five different answers – and none of them are wrong. In this workshop, we define legacy code as code without tests. Why? Because without tests, making changes becomes risky and error-prone. To refactor safely, we first need to build a solid understanding of what the code does, and write tests around it.

This session explores practical techniques to make legacy code more testable and maintainable, so you can work with it more confidently.

This workshop will be organized on-site in cooperation with the NS - Nationale Spoorwegen (Utrecht)!

Introduction:
During the workshop, you'll get hands-on experience with several techniques to bring legacy code under test. We'll also cover how to add new, tested features to untested codebases.
The workshop blends practical exercises with theoretical principles from Michael Feathers' Working Effectively with Legacy Code. We’ll emphasize interaction, peer learning, and lots of space for discussion.

What you’ll learn (objectives):

• Understand what characterization tests are and how they can help
• Learn techniques to break dependencies and isolate code for testing
• Practice adding safe, tested features to legacy code
• Give names to techniques you might already use instinctively, so you can better communicate about them
• Gain confidence working in legacy systems without fear of breaking things

Who should attend?
Software developers (Java/Kotlin developers) who work with existing codebases and want to strengthen their legacy code handling skills.

What you’ll need:

• Basic understanding of object-oriented programming and unit testing
• Your own laptop + charger
• Make sure you can build Java 17 with Maven (and that you are able to run unit tests)
• Recommended: IntelliJ IDEA. Other IDEs are welcome, but IDE-specific issues are your own responsibility ;-)

Agenda:
16:00 - Walk-in & Food
17:00 - Start workshop
20:00 - End of the workshop
20:00-20:30 - Closing & Drinks

Location:
NS - Nationale Spoorwegen
Katreinetoren - 'De Kookstudio'
Stationshal 17
3511 CE Utrecht

Registration:
A valid ID is required to enter the building