Javaforum Göteborg

Welcome to Javaforum Q4 2025

17:00 Registration / mingle / sandwich

17:30 Intro

17:35 Dependency Hell is a Real Place (45 min, English)
Package managers such as Maven, NPM, NuGet and Cargo have made it absolutely trivial to reuse other peoples code, and the result is often interpreted as a productivity boom. But dependencies are not all sunshine and rainbows. They are resources with risks! Come and listen to rants and wisdoms about dependencies, and how Maven is uniquely designed to help Java developers avoid burning in dependency hell!

Emanuel Palm is today Competence Lead within Java and Cloud at Nexer. He has previously worked as doctoral researcher, software architect, fullstack developer, backend developer and mobile app developer. He cares deeply about software craftsmanship and the software industry at large. You can read his thoughts on his blog, systemsandsociety.com

18:25 Java Performance Update 2025; from JDK 21 to JDK 25 (45 min, English)
JDK 25 has just been released and is packed with performance improvements compared to JDK 21, allowing your unchanged application code to run even faster. In this talk, we will take a closer look at 13 concrete performance improvements made between JDK 21 and JDK 25 involving both the standard Java libraries, the JIT compiler, and the garbage collectors.

Among these improvements is the newly introduced 'Stable Value' preview feature, which allows a field to share the benefits of both mutable and immutable fields simultaneously.

We will learn how this new feature works, how much performance can be improved, and how your code can take advantage of it already today. We will also explore some of the design considerations made, the importance of developer feedback, and how the JDK engineers evaluate performance in a world of conflicting optimization criteria and varying platform properties.

Per Minborg works in the Java Core Library team at Oracle and is also a member of the Panama project team. He is an inventor and developer with more than 20 years of Java coding experience. He has been a frequent contributor to various open-source projects, is a regular speaker at events, Oracle JavaOne alumnus, and co-author of the publication Modern Java.

19:15 Modern Java Puzzlers (45 min, English)
Since JDK 9, Java, as a language, has evolved faster than at any point in its 30-year history. For developers, this is great as it means we get more new features to make our code more concise, yet hopefully, easier to read and understand.

All new language features also bring their quirks and possibly unseen consequences.

In this fun interactive session, we’ll examine a range of recent language features and pose questions to the audience about how the code works and what it does.

We’ll cover many of the new language features from recent releases, including switch expressions, sealed classes and pattern matching. We’ll even look at some curious ways special characters can be used in unexpected ways.

The answers will most definitely not always be as you expect.

Simon Ritter is the Deputy CTO of Azul. Simon joined Sun Microsystems in 1996 and spent time working in both Java development and consultancy. He has been presenting Java technologies to developers since 1999 focusing on the core Java platform as well as client and embedded applications. At Azul, he continues to help people understand Java and Azul's JVM products.

Simon is a Java Champion and two time recipient of the JavaOne Rockstar award. In addition, he represents Azul on the JCP Executive Committee, the OpenJDK Vulnerability Group as well as the JSR Expert Group since Java SE 9.

20:00 After the talks some snacks and drinks will be served. A perfect occasion to mingle with other developers