In this 4-day intensive course, you'll learn all relevant innovations introduced in Java versions 12 to 21 – compactly, clearly, and with a strong focus on practical application in everyday project work.
Discover how modern language features like Records, Switch Expressions, Text Blocks, Pattern Matching for instanceof, and Sealed Classes can make your code more elegant and maintainable.
You'll also explore valuable additions like Helpful NullPointerExceptions and new methods in core APIs such as String, Stream, and Files.
We’ll also cover Garbage Collection improvements (G1, Parallel GC, ZGC, Shenandoah) and performance enhancements like CDS Archives and specialized TreeMap implementations.
In the second part, you’ll explore features introduced in Java 18 to 21 – including Virtual Threads, Record Patterns, and Pattern Matching for switch, enabling more concise and expressive logic.
You’ll also get to know the Sequenced Collections API, UTF-8 by default, the Simple Web Server, and more improvements across standard APIs.
Once again, we’ll dive into Garbage Collector enhancements (especially Generational ZGC) and performance features like alternative locking mechanisms.
Through practical exercises based on real-life scenarios, you’ll immediately apply what you’ve learned and anchor your knowledge.
The course concludes with a look at preview features in Java 21: Structured Concurrency, Scoped Values, the Foreign Function & Memory API, and the Vector API – a glimpse into Java’s exciting future.
This course is for Java developers who want to stay current – hands-on, accessible, and packed with “aha” moments.
Whether you're planning a migration to Java 17 or 21, or you already have first-hand experience – this combo course gives you a comprehensive understanding of the latest LTS versions.
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:
Additional Features:
Bugfixes:
API Enhancements:
Garbage Collection:
Performance:
Deprecations & Removals:
Looking Ahead:
I’m a Java expert with over 20 years of experience – as a developer, architect, CTO, performance coach, and trainer.
I’ve designed enterprise-scale systems for companies like 1&1, IONOS, and ICE Services, modernized legacy apps, and helped teams build robust, maintainable, and high-performance Java software.
With HappyCoders.eu, I’ve built one of the most widely read Java blogs in the German-speaking world. I speak at conferences and Java User Groups – and often receive praise for making complex technical topics easy to understand.
What you’ll get from my courses:
I don’t just teach features – I show you how to develop better software with a deep understanding of Java.