Amsterdam Java User Group

Join in with the latest Amsterdam JUG Meetup at BeFrank, De Entree 99-197, 1101 HE Amsterdam.

Agenda

17:00 - Doors Open (And Food!)
17:30 - 18:00 Talk 1: "When the Currents Take You: Why Teams Must Take Ownership of Technical Debt" by David Veen
18:00 - 18:30 Talk 2: "From CRUD to Durable: Adding Temporal Workflows to the Spring Pet Clinic" by Geertjan Wielenga
18:30 Short Break
18:45 - 19:15 Talk 3: "Stop Building AI Tools Backwards" by Jonas Jebing
19:30 - End

Talk 1: "When the Currents Take You: Why Teams Must Take Ownership of Technical Debt" by David Veen

Technical debt is one of the most widely used metaphors in software engineering — and one of the most poorly understood. Since Ward Cunningham coined the term in 1992, the concept has drifted far from its original meaning, becoming a catch-all for anything wrong with a codebase. This imprecision has consequences: when everything is tech debt, nothing is prioritized.

This talk draws on Lou Franco's excellent book Swimming in Tech Debt (2025) and the author's first-hand experience with a startup where accumulated technical debt ultimately contributed to the decision to shut down operations. Franco's framework of forces and dimensions offers a structured, data-driven starting point for analyzing, communicating, and addressing tech debt that moves beyond vague appeals for "refactoring time."

We examine what tech debt is, why it is chronically underprioritized in organizations, and what development teams can do about it. Giving teams the tools to take ownership is key: to make debt visible, tie it to business outcomes, and advocate for targeted investment. The alternative is not some abstract risk of stagnation. The speaker's startup experience illustrates what happens when tech debt goes unmanaged for too long: when the moment comes to adapt, the codebase won't let you.

Talk 2: "From CRUD to Durable: Adding Temporal Workflows to the Spring Pet Clinic" by Geertjan Wielenga

Spring Boot applications excel at handling synchronous CRUD operations, but what happens when you need to send appointment reminders days in advance, manage multi-year vaccination schedules, or orchestrate complex payment workflows that must survive server restarts?

In this talk, we'll transform the classic Spring Pet Clinic application by integrating Temporal.io -- the free and open source durable execution platform that makes long-running processes reliable by default.

You'll learn how to:

• Identify which operations benefit from Temporal (and which don't)
• Implement appointment reminders that survive server restarts
• Build multi-year vaccination schedules with Signals and Queries
• Apply the Saga pattern for reliable payment processing
• Test workflows with Spring Boot's testing framework
• Deploy workers separately from your web tier

We'll start with a 5-minute "Hello World" workflow, then progressively build real Pet Clinic features, showing complete code examples you can use in your own applications.

By the end, you'll understand when and how to add Temporal to Spring Boot apps, with practical patterns for background jobs, scheduled reminders, and complex orchestration.

Talk 3: "Stop Building AI Tools Backwards" by Jonas Jebing

Many current AI tools are designed in ways that inadvertently hinder human learning and skill development by removing critical reasoning loops. Instead of empowering practitioners, these tools often prioritize immediate outcomes over the process of understanding.

This talk explores how we can shift our approach to building AI tools that act as instructors rather than "junior co-workers." We will delve into the theory of Retrieval Practice and introduce the EDGE framework (Explain, Demonstrate, Guide, and Enhance) to design AI interactions that reinforce human learning, facilitate social reasoning, and encourage team-based cumulative iteration. Join us to learn how to build AI-augmented workflows that accelerate human execution in-process rather than replacing it.

The talk is based on this blog post with the same title “Stop building AI tools backwards” by Hazel Weakly. In addition to what the blog post covers, we’re going to take a deeper look at when and how these patterns can be applied.

Join in with the latest Amsterdam JUG Meetup at IBM, Johan Huizingalaan 765, 1066 VH Amsterdam.

Note: All participants can park their car for free at the IBM parking in front of the office. There are two electric charging stations too for those that drive an electric car.

Agenda

18:00 - Doors Open
18:00 - 18:30 - Food/Drinks and networking
18:30 - 19:15 - The Missing Protocol: How MCP Bridges LLMs and Data Streams
—Viktor Gamov
19:15 - 20:00 - Bootiful Spring AI—Josh Long and James Ward
20:00 - 21:00 - Networking drinks

Abstracts

The Missing Protocol: How MCP Bridges LLMs and Data Streams
—Viktor Gamov

Nobody’s talking about this: MCP isn’t just another way to build chatbots. It’s the bridge we’ve been missing between AI reasoning and real-time data systems.

Teams build AI applications that work great in demos but fall apart with production data. Your agents analyze historical reports but can’t tell what’s happening in your Kafka streams. They’re blind to schema changes and disconnected from events that matter to your business. Instead of treating streaming platforms like black boxes, you expose them directly to your agents via MCP protocol. Suddenly, your AI doesn’t just read about data—it lives inside your data flows.

Learn what becomes possible when you stop thinking about AI as an external service and start treating it as part of your streaming architecture. We’ll build systems where agents subscribe to real-time events, reason about evolving schemas, and make decisions that ripple through your data platform.

Bootiful Spring AI—Josh Long and James Ward

The age of artificial intelligence (because the search for regular intelligence hasn't gone well..) is nearly at hand, and it's everywhere! But is it in your application? It should be. AI is about integration, and here the Java and Spring communities come second to nobody.

In this talk, we'll demystify the concepts of modern day Artificial Intelligence and look at its integration with the white hot new Spring AI project, a framework that builds on the richness of Spring Boot to extend them to the wide world of AI engineering.

Bios

Viktor Gamov is a Principal Developer Advocate at Confluent, founded by the original creators of Apache Kafka®. With a rich background in implementing and advocating for distributed systems and cloud-native architectures, Viktor excels in open-source technologies. He is passionate about helping architects, developers, and operators craft systems that are not only low-latency and scalable but also highly available.As a Java Champion and esteemed speaker, Viktor is known for his insightful presentations at top industry events such as JavaOne, Devoxx, Kafka Summit, and QCon. His expertise spans distributed systems, real-time data streaming, JVM, and DevOps. Viktor has co-authored “Enterprise Web Development” and “Apache Kafka® in Action”. Follow Viktor on X - @gamussa to stay updated with Viktor’s latest thoughts on technology, his gym and food adventures, and insights into open-source and developer advocacy.

Josh Long (@starbuxman) has been the first Spring Developer Advocate since 2010. Josh is a Java Champion, author of 7 books (including "Reactive Spring") and numerous best-selling video training (including "Building Microservices with Spring Boot Livelessons" with Spring Boot co-founder Phil Webb), and an open-source contributor (Spring Boot, Spring Integration, Axon, Spring Cloud, Activiti, Vaadin, etc), a Youtuber (Coffee + Software with Josh Long as well as my Spring Tips series ), and a podcaster ("A Bootiful Podcast").

James Ward is a Professional software developer since 1997, with much of that time spent helping developers build software that doesn't suck. A Typed Pure Functional Programming zealot who often compromises on his ideals to just get stuff done. Currently a Developer Advocate for AWS.