Live-Refactoring a realistic codebase

The exercise I propose to you here is a raw (anonymized) code sample I recently saw at a client during a Clean Code workshop. No tests, no spec. We found ourselves discussing hours on that code, with very little need for more information, and I'd like to try it out with you folks.

Check the code out, and try to give it a run before the event:

Topics on the menu:
- Immutability
- Split Loops
- Reducing Cognitive Complexity
- DRY principle
- Abuse of FP-style coding without adopting the FP mindset
- Command-Query separation
- Naming
- Coupling

Format: I will type and debate topics with the audience, asking you how to proceed further. So you'll be in control :)

Although the code is in Java, the discussion will be generally applicable to most languages (C#, PHP, TS, Kotlin..)

About the speaker (entertainer):

[rlresende]

Hi, my name's Robert from Brazil. I'm Java developer here in Brazil and I would like to congratulate for the presentation... It was really nice!

[mohamadsharifi]

Great job. I really like your way of teaching, and kata style videos. Thanks for sharing such a great content.

[adhithyansridhar]

wow. Great insights and take aways, Thanks much

[rodelias]

Awesome presentation! Thanks a lot Victor!

[Kobayashhi]

Laugh driven development is the greatest.

[mchlg]

Well done Victor. High level as always. High 5 for U :)

[PeterGfader]

The Zen Mode should show line numbers:)
GREAT video @Victor
😊