Dublin Java User Group

In time honoured fashion, our first DubJUG events of the year are linked with the jChampions Conference, and today we're announcing our first visiting Java Champions of 2026, Cay Horstmann.

TALK ONE: Effective Pattern Matching in Java
Since Java 14, the Java switch and instanceof statements have been enhanced, in multiple phases, to support pattern matching and a "data-oriented" programming style.

In this presentation, Cay explores when this programming style is beneficial, and why. (Spoiler: Not as often as one might think from Oracle's presentations, but when it does apply, it is truly useful.)
Cay describes the syntax of pattern matching, as it has evolved, and shows how it will be further enhanced in upcoming versions of Java. He warns of corner cases of the switch syntax where modern usage clashes with legacy behavior.

The talk concludes with a set of rules when to use pattern matching and "data orientation" now, how to prepare for future enhancements, and when to stay away.

TALK TWO: Virtual Threads, Structured Concurrency, Extent Locals: When to Use Them, and How.
Project Loom introduces a lightweight threading model to the Java platform.

At first, the blogosphere erupted in displays of denial. Why do we need something new when threads and reactive programming have served us well? The next stage was anger. People tried to use virtual threads with use cases for which they were definitely not designed, and were upset that the results were bad.

The purpose of this talk is to help the audience skip the next two stages of grief and skip ahead to acceptance. Cay will analyse typical concurrent programming tasks and show how to assess their Loom-friendliness. He will dig into the new concepts of structured concurrency and extent locals and give examples of when to use them, and when to stick with existing practice.

As a result, attendees should be able to walk away with a more nuanced understanding of when and how to employ virtual threads in their systems.

OFFICIAL SEATS >>>>>
Check your schedule first (it's not cool to not show!)
https://ti.to/dublin-java-user-group/2601-jchampions-cay-horstmann

In time honoured fashion, our first DubJUG events of the year are linked with the jChampions Conference, and today we're announcing our second visiting Java Champions of 2026, Tom Cools.

TALK ONE: Optimizing Santa's travels in Java with Timefold
Every Christmas Eve, Santa faces a monumental challenge: delivering gifts to millions of children around the world in just one night. There’s no time for detours, and a well-crafted plan is essential!

Tom has helped Santa find the optimal travel route for his journey using Timefold, an open-source AI solver. By setting up some basic domain classes, he's been able to tackle vehicle routing problems without getting lost in the magic (aka math).

Through a series of live demos using our favourite programming language (ahem, Java!), Tom will show you practical examples in action and which ensured everyone got their presents under the Christmas tree!

And you will leave with a powerful new tool in your problem-solving toolbox.

TALK TWO: Braving the Change: Recalibrating to new realities
Change is the only constant in our industry’… but they never told us it would go this fast. With the recent evolutions in AI, ‘change’ has shifted from a ‘constant’ to something better described as ’exponential,’ sparking excitement for some and existential dread for others.

In this session, Tom will discuss some insights into dealing with change inspired by the real big changes in our lives, exploring the emotional aspects of change, contextualize our relation to change and discuss the three essential skills needed to deal with evolving landscapes.

After leaving this session, you’ll be better prepared for whatever change might come on your path, whatever shape that change might be.

OFFICIAL SEATS >>>>>
Check your schedule first (it's not cool to not show!)
https://ti.to/dublin-java-user-group/2603-jchampions-tom-cools