NLJUG – Nederlandse Java User Group NLJUG – de Nederlandse Java User Group – is opgericht in 2003. De NLJUG verenigt software ontwikkelaars, architecten, ICT managers, studenten, new media developers en haar businesspartners met algemene interesse in alle aspecten van Java Technology.
The day before JFall 2024 sixty-two enthusiastic Java developers got together in Veenendaal for Masters of Java: the annual coding challenge for Java Developers of all levels. The event was organized by NLJUG, with First8 Conclusion as the main sponsor responsible for the software and challenges.
The developers had signed up in 34 teams. For some, it felt like an annual reunion, while for others it was their first time – exciting! What kind of challenges would there be? What knowledge would be needed? They would soon find out.
The Rules of Masters of Java
Each year, the participants are presented with five diverse challenges. For every challenge they are given 30 minutes to submit a solution. Hardcore Java skills are essential, and the tasks range from developing algorithms to using well-known and less common Java APIs. Google searches aren’t allowed, but teams are provided with an extra keyboard. Participants can only use the standard Java SDK, with no framework knowledge required.
For each task, participants were given a concise Java project, usually allowing changes to just one file. working on a task, teams can verify their solutions through tests and occasionally earn bonus points completing extra tests. Hidden tests may be executed after submission to double check the solutions.
For correct submissions, teams earn the remaining time as points, plus a bonus.
This Years Challenges
The team at First8 had yet again prepared a great set of challenges, carefully curated in several iterations.
- Roman Numerals – A warm-up exercise to ease into the Masters of Java. This task involved converting Roman numerals to our decimal system.
- Hierarchical Timing Wheels – An algorithmic challenge requiring participants to complete an HTW algorithm, enabling efficient handling of numerous timers across different types of clocks (e.g., our 24-hour clock or Mars’ clocks).
- Hacking the Server – Participants needed to “hack” an old CI/CD server to get it running. Did anyone spot the Wolfenstein3D and other retro references?
- Emoji Palindrome Finder – Perhaps the most hated and discussed challenge 😊 (we say this proudly). Participants had to find palindromes in text including emojis, for which all skin tones were considered equal.
- Disappearing Tasks – The ultimate bug hunt: Why were certain tasks disappearing in this implementation?
The Winners
The competition was fierce, with the top 5 positions changing after every challenge. The final decision came down to the last assignment! After the Disappearing Task challenge this top 3 of talented Masters of Java teams were presented with First8’s great Board Game Packages:
- Thomas Withaar and Maarten van der Zwaart | Team OVSoftware | 8,262 points
- Jasper van Merle | Team camel_case | 7,198 points
- Johan de Jong | Team EatSleepCodeRepeat | 6,313 points
Congratulations to all the winners on this fantastic achievement!
To all other participants: thank you for joining, and we hope to see you again at Masters of Java 2025!
Curious about the challenges?
You can check out all the challenges from 2016 onwards on GitHub – First8/mastersofjava