Package encapsulation with Spring Modulith && Solving issues with OpenTelemetry

We're excited to announce our next meetup Dec 3rd, 2024! As usual, we'll take care of food, drinks and awesome sessions - you just need to bring you ;-)

This meetup will feature two talks aimed at (Java) developers:

• Jos Roseboom will kick off and save our brains cognitive load by sharing with us how he simplified their code using package encapsulation with Spring Modulith.
• Next, Cees Bos wil explain to us how he solved production issues with OpenTelemetry.

All sessions will be presented in English; RSVP now for an evening of learning and fun!
The meetup will be at the OpenValue office in Utrecht (directions: https://route.openvalue.eu), enough free parking spaces available.

Agenda
17:30 Walk in
18:00 Food
18:30 Talk 1 (see below)
19:30 Break
19:45 Talk 2 (see below)
20:45 Drinks

First talk: How package encapsulation with Spring Modulith simplified our code
Have you ever felt there is too much relevant code for your current task to fit into your brain? Resulting in some StackOverflow in your head: a brain explosion.

Multiple factors contribute to this, one of them being the package structure of the code. In this talk I will explain why we wanted to refactor our package structure from horizontal (grouped by technical role like ‘controller’, ‘service’) to vertical (grouped by subject like ‘order’, ‘product’). I will show you how Spring Modulith can restrict access between packages and how you can gradually introduce it. On top of that, I will show some refactorings that we often used to break dependencies.
After this talk you will know why vertically slicing your packages might be a good idea and how you can use Spring Modulith to help you with that.

About Jos
Jos gets a smile on his face when he makes other people happy by letting a computer do what they don’t like to do. He has been trying to do so professionally for the past 16 years. Nowadays with Java and sometimes with Javascript, but wasn’t afraid of other languages like Ruby, Objective C and PHP in the past.

In his spare time, Jos likes to play tennis. He is a trainer/coach for kids playing the typical Dutch sport korfball.

Second talk: How I solved production issues with OpenTelemetry (and how you can too)
In today's fast-paced world, ensuring the reliability of your Java applications is critical. But how do you effectively identify and resolve production issues before they escalate? With cloud-native applications, it can be even more difficult because you can't log into the system to get some of the data you need. The answer lies in observability - and more specifically, OpenTelemetry.

In this session, I'll take you behind the scenes of several production problems I've solved using OpenTelemetry. You'll learn how I uncovered critical problems that were invisible without the right telemetry data - and how you can do the same. From tracking down elusive bugs with traces to uncovering system bottlenecks with metrics, OpenTelemetry provides the tools you need to truly understand what's happening in your application in real time.

A key concept in all this are traces, especially in microservices landscapes. That's because architecture diagrams often don't tell the whole story. I'll show you how these traces can help you build a service graph and save you hours in a crisis. A service graph gives you the overview and helps you to pinpoint where to look for problems.
Whether you're new to observability or an experienced professional, this session will give you the practical insights and tools to dramatically improve the observability of your application - and change the way you handle production issues. Solving problems is much easier when you have the right data at your fingertips.

About Cees
Observability enthusiast and Grafana Champion, always looking for ways to improve software with better observability and what new insights can be gained. Delivering reliable software is always my priority. Combining existing tools often results in new ways to get an even better view. I work for OpenValue as a software & observability engineer and SRE.