Event Sourcing and JCast!

BeJUG is back in May and we're heading to Ghent this time!

A big thank you to Inetum for hosting us again!

We have two great speakers ready to share some knowledge: Hannes Lowette is going to talk to us about Event Sourcing and JCast podcaster Maarten Casteels is going to tell us more about his Java podcast journey!

Come join us for this next event!

Schedule

• 18:00: Doors open + Food and Drinks
• 18:45: Intro and BeJUG updates
• 18:50: Talk 1
• 19:35: Little break
• 19:45: Talk 2
• 20:30: Mingling + Drinks

Topics

Event Sourcing: dealing with an eventful past
"At a certain level of abstraction, all complex systems are message passing systems." - Grady Booch. In software, we are often passing messages around between components, services and even systems. We do so in synchronous and asynchronous ways. The second half of Grady's tweet talks about how societies use memes to pass information across time. In software, we use the state of our system to do the same: everything we write to storage is, in essence, a message for our future system.

If we use Event Sourcing as our persistence pattern, we are making this message passing in time much more explicit in our software. And there are other benefits too! For instance, we are sacrificing a lot less information compared to classical relational databases. We also enable point-in-time capabilities for our entities. And we are much more likely to be able to fulfill future business requests based on old data.

Does that sound complex? It doesn't have to be. In this talk, I will given an introduction to what Event Sourcing is, how to fit it into a CQRS architecture, and what design patterns you can use to unlock its full potential.

About Hannes
Hannes is a developer, a coach and a father of 3.

In software development, he has always had a passion for performance, databases, distributed systems and large scale applications. He's always weighing every solution's benefits against its drawbacks, reducing friction where possible.

As a coach, he is enthusiastic about knowledge sharing, personal growth and building careers. Building a company culture around learning is what gets him out of bed.

In his free time, when he’s not building LEGO® castles with his kids, he likes to spend time building guitars, playing chess, mountain biking and doing all round geeky stuff.

You can often find him on stage at the conference afterparty, especially as the guitarist of Dylan Beattie & the Linebreakers.

When the Spark Shows Up, Don’t Ignore It
Most ideas don’t fail. They just never get started.
I had been thinking about starting a podcast for a long time, but like many ideas, it stayed in the background until the spark showed up.

When Oumaima and Viktor brought up the idea for JCast, something clicked. We didn’t overanalyze it. We didn’t wait for the perfect setup. We just went for it.
In this talk, I’ll share how that one decision turned into something much bigger than expected. Not because we had a perfect plan, but because we followed the energy, accepted the trade-offs, and kept going.

JCast is the story, but the lesson is broader: sometimes the most important thing you can do is recognize the moment and act on it.

About Maarten
Maarten Casteels is a Java developer passionate about clean code, TDD, and continuous learning. He is one of the co-creators of JCast, a podcast he started with Oumaima and Viktor, driven by curiosity, conversation, and a willingness to follow a spark when it appears.

Additional notes:

• This meetup includes food. Please keep your RSVP status up to date so we do not waste any of our food.
• Some pictures might be made. If you feel uncomfortable about this, please mention this to the organizers (or anyone with a camera).