Java 25 is the new LTS version – and brings the most exciting new features since Java 21: finalized Stream Gatherers, Unnamed Variables & Patterns, and a stable Foreign Function & Memory API. For teams that base their Java upgrades on LTS versions, now is the right time.
In two days, this course brings your team up to the level Java 25 makes possible – clearly explained and immediately applicable.
In this two-day course, you’ll learn all the key enhancements introduced in Java versions 22 through 25 – compact, in-depth, and focused on practical use in real-world projects.
We’ll take a close look at modern language features like Unnamed Variables & Patterns, which improve code readability, and the new Foreign Function & Memory API, enabling secure and efficient access to native libraries. You’ll discover how to use Scoped Values for thread-safe context propagation and how Markdown Documentation Comments help you write more structured, readable documentation.
One of the highlights is the new Stream Gatherers API, which significantly simplifies complex stream aggregations. You’ll also learn how Compact Source Files and the new Instance Main Method make it easier to start new projects quickly.
Of course, we’ll also cover numerous API enhancements and important under-the-hood performance improvements, including how to synchronize virtual threads without pinning – a major step toward building highly scalable applications.
In hands-on exercises, you’ll directly apply the new features and gain a deep understanding of how to use them effectively in your projects.
At the end of the course, you’ll get a preview of what’s coming next – including Primitive Types in Patterns, instanceof, and switch, Stable Values, the Vector API, and a redesigned Structured Concurrency API.
You’ll find a complete overview of all features in my Java 25 features article.
This course is designed for Java developers who want to stay ahead of the curve – with a clear, practical, and well-structured approach.
Whether you’re upgrading from Java 17 or already working with Java 21 or later and want to systematically explore the features up to Java 25 – this course provides the knowledge you need to future-proof your project.
If you want to tackle Java 21 and 25 together, you’ll find the right combined course here.
We won’t follow the listed order strictly. Instead, we’ll alternate between major features, smaller topics, and theory – keeping the course engaging and balanced, and helping you better retain the material.
Major Features:
Other New Features:
API Enhancements:
Garbage Collection:
Performance / Memory Footprint:
Deprecations & Removals:
Looking Ahead:
I’ve been working with Java for over 20 years – as a developer, CTO, trainer, author, and speaker.
In that time, I’ve helped companies modernize complex systems, write performant code, and develop their teams.
With HappyCoders.eu, I’ve built one of the most widely read Java blogs in the German-speaking world – thousands of developers read my articles on the Java 25 features every day.
My goal: to teach complex topics in a way that is understandable, practical, and immediately applicable.
This training can only be booked for teams. If you’d like to attend as an individual, I offer two courses (in German) through ppedv:
I recommend a maximum of 12 participants per training – that way I can give everyone individual attention. There is no minimum: I charge per training, not per person.
The easiest way is the request form or an email to schulung@happycoders.eu. Right after submitting, you can book a video call via Calendly, where we discuss the details. You’ll then receive a concrete offer from me.
Ideally, you’re familiar with Java 21. If you’ve worked with Java 17, you’ll be fine too – the most important differences are put into context during the course. In general, I recommend at least two years of practical Java experience.
All participants need an up-to-date IDE with at least Java 25 – I use IntelliJ IDEA myself. Java 25 or later should also be installed in the terminal, as we’ll run some of the exercises there.
Each day has six hours of net training time – usually with two short breaks and a longer lunch break in between. We align the exact schedule with your working hours – that’s flexible.
About half theory, half practice: a short theory phase is followed directly by applying it to code – with examples from real projects. Listening alone doesn’t help much; the knowledge has to be used immediately for it to stick.
Yes, that’s no problem. Dropping topics or weighting them differently – as long as I don’t have to restructure the training materials, there are no extra costs.
If you need more extensive changes – for example, combining content from different courses or adding entirely new topics – I’ll be happy to prepare an individual offer.
Within the existing agenda, the weighting can be adjusted: shortening topics, setting priorities, changing the order. That’s free of charge.
Beyond that, more far-reaching adjustments are possible – such as combining content from different courses or completely new topic blocks. This involves extra effort, so I’ll prepare an individual offer for it.
We usually use Zoom. If you prefer your own platform – for example, Microsoft Teams or Google Meet – I’m happy to work with that. Just let me know in advance.
Yes. Before the training, you’ll receive the exercises as a Git repository so you can get started right away. After the training, you’ll also receive the slides – including all solutions to the exercises.
Travel expenses are charged as a flat rate – depending on the training location and the number of overnight stays required. The exact amount is part of the individual offer I’ll send you.
Yes. For multiple booked trainings or follow-up bookings, I can offer a volume discount. We’ll discuss this in the video call, and I’ll include it in the offer.
Just write to me – I usually reply within 24 hours.
Or book a free video call right away, and we’ll discuss everything important.