JCON EUROPE 2025 in Cologne, Germany, was a vibrant gathering of the Java community, featuring over 100 sessions, engaging workshops, and a diverse group of attendees from around the world. Representing Karakun, we were actively involved in showcasing our work and solutions, such as OpenWebStart, while engaging with the community to capture the current pulse of Java development.

Java: Time-Tested and Continually Evolving

Our survey, commemorating Java’s 30th anniversary, revealed that Streams remain a favourite among developers. Close contenders included Records, Virtual Threads, and Type Inference. The community values features that enhance pragmatism and modernity in their development workflows.

When it comes to Java version usage, a significant portion of developers have transitioned to newer Long-Term Support (LTS) versions. Java 17 is widely adopted, with nearly half of developers already using Java 21. However, older versions like Java 8 and 11 still see considerable usage, indicating a gradual migration trend within the community. We talked even to people that are maintaining applications build on Java 1.4 and Java 1.5 showing the long term capabilities of this platform!

Frontend Technologies: A Spectrum of Preferences

In the realm of frontend development, React leads the pack, followed by Vue and Vaadin. Notably, HTMX is gaining traction. However, many participants expressed a primary focus on backend development, highlighting the specialized roles within the developer ecosystem.

AI Tools: Enhancing Developer Productivity

Artificial Intelligence is increasingly becoming an integral part of the developer’s toolkit. Our observations align with broader industry trends, where tools like GitHub Copilot and ChatGPT are commonly used for tasks such as code completion, refactoring, and debugging. These tools are not only boosting productivity but also reshaping development workflows.

Interestingly, developers are adopting multiple AI tools simultaneously to leverage their unique strengths. This multi-tool approach allows for a more versatile and efficient development process.

Beyond Java: A Polyglot Developer Landscape

While Java remains central, many developers at JCON EUROPE 2025 reported using additional programming languages in their daily work. JavaScript and TypeScript were among the most commonly used, especially for frontenddevelopment. Python also featured prominently, particularly in areas like data analysis and scripting. Other languages, such as Kotlin, Rust, C# and Go, were mentioned, reflecting the diverse and polyglot nature of modern software development.

Community Engagement and Networking

Our booth, situated between the conference halls and the complimentary beverage area, became a hub for meaningful interactions. Discussions ranged from technical topics to career opportunities and shared experiences within the Java community. We were particularly pleased to see a significant representation of women and a mix of attendees ranging from students to seasoned professionals.

Diverse Sessions Reflecting a Dynamic Landscape

The conference agenda encompassed a wide array of topics, including Cloud-Native Java, Microservices, AI Integration, and Performance Optimization. The lineup featured a mix of speakers from major corporations like Oracle and IBM, alongside independent experts and active community members. We were happy to contribute to the outstanding schedule with the talk “From Bugs to Brilliance: Testing Toolbox in Action” by our expert François Martin.

Conclusion

JCON EUROPE 2025 highlighted the dynamic and diverse nature of the Java community. With a blend of established practices and innovative approaches, Java continues to be a cornerstone in software development and with this virbrant, open and innovative community a safe option for modern software development. Many conversations and talks from the conference schedule proved that Java is surely safe for “AI age” both by having frameworks and libraries making it easy to leverage from the capabilites availabe through the technology and also having the proven track record of long term maintainabilty.

We’re already looking forward to the next edition and the continued evolution of our community.