When I first started attending conferences, I diligently tried to write down notes and publish them. It forced me to actively listen to the talks I was attending. With the number of conferences rising, I couldn’t keep the rhythm. When I switched my career path to Developer Advocate, I drastically diminished the number of talks I attended in favor of the hallway track. As a result, the last conference “report” I wrote was JPrime’s in 2022.
This week, I was privileged to speak at DevOps Days Kansas City. The event was co-located with and part of KCDC. It was my first edition for both. As I’m returning to engineering, the number of conferences I’ll attend in the near future will probably be very low, if not zero. Hence, I wanted to revive the tradition of note-taking, as well as give my opinion on the conference.
The Talks
At conferences, I attended talks depending on several goals:
- I want to deep-dive into a subject I already know, and hope to learn a couple of new things. I’ll judge the talk positively if there’s only one, but negatively if I learned nothing.
- I’ve heard about something and want to learn more about general concepts.
- I go to a talk that I know absolutely nothing about, to reduce the number of unknown unknowns.
Here are the talks I attended. When possible, I link to a recorded edition of the talk or the slides.
Home Lab – Private Cloud on a Budget
I stopped at the part before the dash, and expected a talk on Home Automation. The talk was instead about creating your own “cloud” at home, as the name states. I guess jet lag hit me more than I expected. Despite my mistake, the talk felt engaging, touching on some parts of what I’m doing at home, albeit in a much more “build” fashion (as opposed to “buy”).
Loom is More Than Virtual Threads: Structured Concurrency and Scoped Values
I haven’t coded with Java virtual threads yet, and the last talk I attended on the subject was probably more than one year ago. The speaker delivered and refreshed my memory. TIL: Structured Concurrency won’t be released as part of Java 25, but will still be in preview state.
15 Productivity Tips to Accelerate Your Apache Maven Builds
I’ve been using Maven for a long time, and I wanted a deep dive. Case in point, TIL: forkCount.
Take the Polar Plunge: A Fearless Introduction to Apache Iceberg®
I heard about Apache Iceberg before; I think I even read a post about it. Yet, I’m unable to tell what it is for, what role it plays, and in which context. I decided to go to this talk to get an introduction.
If there’s one thing to remember, it’s that Iceberg is a data format for Data Lakehouses, composed of:
- data files
- manifest files
- manifest files lists
- metadata files
https://mirrors.dotsrc.org/fosdem/2025/ub5132/fosdem-2025-4701–replacement-take-the-polar-plunge-a-fearless-introduction-to-apache-iceberg-.av1.webm?embedable=true
Epic App Performance Starts with the Database
This talk is targeted at developers. I believe the concepts explained in the talk are fundamental for any programmer worth their salt.
You can improve your app code as much as you want, but you won’t be able to improve the database performance. Therefore, it’s important to know a couple of tricks to get the best out of the database. The speaker tells a story about adding a database index that solved a huge performance bottleneck.
Tables work a lot like written address books. When you don’t have an index, you need to search; you must search everywhere, known as full table scans. An index is like grouping an address book by letter: it reduces the search space.
From a developer’s point of view, conditional querying with no index is like a loop, with conditions. Querying with an index is akin to a hash table lookup.
- Focus on filters and relations
- Expect only one index to be used per table in a query
- Avoid
SELECT *and specify fileds - Field order is important when creating indexes, as they will need to match the queries
WHEREclause
Follows a demo, which uses OpenTelemetry to measure performance! The demo goes through the points seen above, improving a query’s performance step by step.
Here’s the recording and here are the slides.
The Amazing Features of Modern Java
The talk is from Venkat Subramaniam. Venkat’s talks are based on code, not slides. This presentation compares “Java of the past” to the more modern ways Java takes on specific features. Here’s the list of features he went through in this talk.
switchexpressions, as opposed toswitchstatements- Text blocks
- Records. TIL: compact constructors
- Sealed classes
Typescript can do that?
Even though I love the idea of typed JavaScript, the only time I wrote Typescript was for my OpenTelemetry demo. I read a post about TypeScript not so long ago, and it blew my mind. I wanted to know more about the language allowed, beyond the regular tutorials.
Jet lag hit me hard during the talk, and I can’t remember what was said. Check the slides if you’re interested.
82 Bugs I Collected in a Year You Won’t Believe Made It to Production
The talk doesn’t lend itself very well to note-taking, as it is very visual.
The Side Activities
No conference would be considered as such if it didn’t offer side activities. At KCDC, we were literally showered with activities. We started on Wednesday with a speakers’ dinner, make-your-own-burger, and ice creams included. On Tuesday, we started with (light) board games, then we went to the attendee party.
At this point, I need to mention that we also organized unofficial activities. I’m happy to have found fellow board gamers at conferences by chance years ago, and now we play when we get the occasion. I want to give my heartfelt thanks to Micah Silvermann, who not only brought his games on the plane but also took time to set up two sessions and explain the rules.
The Wednesday session was dedicated to Clank!: Catacombs. I’m a big fan of Clank!, and I found this new version even better. One of the downsides of Clank! is the fixed dungeon. If you’re lucky, you get a two-sided board, but it still makes it easy for experienced players to plan their route. In Catacombs, you build the dungeon as you go!
We played Return to the Dark Tower on Thursday. It’s a cooperative game, and Micah’s version has beautiful material. In general, I’m not fond of cooperative games, and this one fit the bill. Worse, we lost to the enemy!
On Friday, the conference finished with a huge prize draw. I remember my first end-of-conference prize draw in the US at DevNexus: the stage was full of amazing prizes. This one was very similar. Unfortunately, I won nothing.
After dinner, we went to the Crown Jewels, a master task copycat. Some participants who agreed were given silly tasks the days before, and they were recorded. During the evening, a judge had to rank them. Unfortunately, I had to leave early because of the accumulated lack of sleep from previous days. It allowed me to wake (very) early and to enjoy a run at 5 AM in Kansas City; it was already 25°C, and the air was quite wet. I went slowly, but I achieved my target of 10k.
Summary
It was my first edition of KCDC, and I loved it. KCDC is a community-organized event, and it shows: you feel that volunteers care for you and are always happy to help.
I’d recommend that you attend, either as an attendee or a speaker.
Originally published at A Java Geek on August 17th, 2025
