Amsterdam Java User Group

About Haoyi Li. Haoyi graduated from MIT, has built infrastructure for high-growth companies like Dropbox and Databricks, and has been a major contributor to the open source community with a focus on JVM developer tools. Haoyi has deep experience in the JVM and related technologies, and has used it professionally to build cloud infrastructure, distributed backend systems, programming languages, high-performance web applications, and much more.

This Amsterdam JUG meetup will be hosted and sponsored by JetBrains, in their office at Terrace Tower, Gelrestraat 16, 1079 MZ Amsterdam. The Event Space is located on the 3rd floor.

Agenda

• 18:00 Doors open, food, and welcome to JetBrains!
• 18:30 Talk 1: Anton Arhipov and Daniil Tsarev (JetBrains) presenting “See Through Spring in IntelliJ IDEA”
• 19:15 Break
• 19:20 Talk 2: Tom Cools (Timefold) presenting “LLMs Can't Optimize Schedules, But AI Can!”
• 19:50 Talk 3: Rijo Sam (ABN AMRO) presenting "Java Beyond Frameworks: Avoiding Lock-In with Agnostic Design"
• 20:20 Break
• 20:30 Talk 4: by Kadi McKean and Charlie Jones (ReversingLabs) presenting "Navigating Compliance: What Developers Can Learn From Driving"
• 21:00 End

Information about the talks:

Talk 1: "See Through Spring in IntelliJ IDEA" by Anton Arhipov and Daniil Tsarev (JetBrains)

Some developers say Spring Boot is magic—but it's not. It's a well-structured, ergonomic framework that takes care of the heavy lifting so you can focus on what matters. But when things don't behave as expected, understanding why can be a challenge.

That's where the Spring Debugger in IntelliJ IDEA comes in.

With Spring Debugger, you get deep, real-time insights into your running application, right inside your IDE. No more digging through logs or guessing what's happening under the hood.

Find answers to questions like:

• Where does this property value come from? Is it overridden somewhere?
• Why is this bean being injected, and which candidate was chosen?
• Is there an active transaction? Who started it?
• Which database is my app connected to? Can I explore it with one click?
• How was this value resolved from profiles, config files, or environment variables?

All the context you need is right there, connected to your code, easy to follow, and just a click away.

You will learn how the Spring debugging support in IntelliJ IDEA helps to gain clarity, troubleshoot issues faster, and turn Spring Boot's inner workings into an open book.

Talk 2: “LLMs Can't Optimize Schedules, But AI Can!" by Tom Cools (Timefold)

LLMs have made remarkable progress, which might suggest they're the answer to everything. However, when it comes to everyday tasks like creating work schedules they tend to fall short. As a result, humans often end up creating a schedule manually, which is usually far from optimal.

Fortunately, there’s a lesser-known branch of AI that excels at complex scheduling. In this talk, we’ll discuss Timefold, a Java based open-source AI solver, and you'll discover how it leverages magic (aka math) to generate optimized schedules.

With a series of live demos, you’ll see this form of AI in action and walk away equipped with a powerful new tool for your problem-solving toolbox.

Talk 3: “Java Beyond Frameworks: Avoiding Lock-In with Agnostic Design" by Rijo Sam (ABN AMRO)

The Problem: Modern Java applications often become prisoners of their frameworks. While tools like Spring Boot and Quarkus accelerate development, they create hidden costs: vendor lock-in, bloated dependencies and rigid architectures. What happens when your project outgrows your framework—or a new, better tool emerges?

The Solution: This talk introduces a layered approach to Java development, isolating framework dependencies while keeping core logic pure with Java and Jakarta EE.

Through examples, you’ll see:

1. How to decouple business logic using JSR standards
2. Strategies to replace framework-specific annotations
3. Cloud integration without framework coupling.

Trade-Offs: Yes, this demands more upfront effort—writing custom persistence layers, rigorous tests, and meticulous docs. But the payoff is code that’s adaptable, testable, and maintainable across frameworks, teams, and decades.

Key Takeaways:

1. Practical patterns for agnostic design.
2. When (and when not) to adopt this approach.
3. Tools to ease the transition.

Join me to rethink Java development: less framework magic, more future-proof code.

Talk 4: “Navigating Compliance: What Developers Can Learn From Driving" by Kadi McKean and Charlie Jones (ReversingLabs)

When driving on a highway, you have to follow the rules of the road. You need a valid license, stick to the speed limit, signal when changing lanes, and stop at red lights to ensure safety for everyone. Skipping these steps risks crashes, fines, and sometimes, jail time.

In open source development, compliance with government regulations is a detour, slowing innovation and creativity. But just like a busy highway, these rules exist to keep us safe, organized, and moving toward our destinations. In this talk, we’ll explore the parallels between the rules of the road and software compliance and how all rules are created equally.

Shedding light on how understanding and adhering to regulatory requirements can empower developers rather than hinder them.

We’ll delve into key government mandates shaping the software landscape, from cybersecurity frameworks to supply chain transparency. We’ll also discuss how ignoring compliance can lead to “accidents” like data breaches and legal penalties and how proactive adoption can create a smoother, safer, and least costly route for innovation.