Get The Most Out of Virtual Threads in Java 25 - A Deep Dive into the Latest Achievements of Virtual Threads, Structured Concurrency and ScopedValues

Structured Concurrency and ScopedValues are available as preview features since Java 21. But since then virtual threads and Structured concurrency have changed a lot and the small amount of remaining issues and shortcomings where finally fixed in Java 24 and Java 25.

To be able to get a deep understanding of how we can use them to their full potential, we will start with an empty Java application. In a live coding session, we will iteratively update it together to a fully functioning, concurrent web application by combining Virtual threads with StructuredTaskScope and ScopedValue.
During the process we will see why we should use ScopedValues instead of ThreadLocals when possible and how to build our own StructuredTaskScopes tailored to our needs with the latest features added by Java 25.

The goal of this talk is to provide to everyone who attends a deep understanding of how these new features work and how they can be used in a real life scenario.

Devoxx

A conference talk covering Java 25 improvements to virtual threads, structured concurrency, and scoped values. Key topics include the fix for the synchronized pinning issue (resolved in Java 24), the redesigned StructuredTaskScope API in Java 25 with the new Joiner interface, and scoped values as a thread-safe alternative to ThreadLocal when using virtual threads across multiple child threads. Practical demos show building a Spring Boot endpoint that runs concurrent blocking calls using StructuredTaskScope, implementing a custom Joiner for flexible subtask result handling, and replacing ThreadLocal with ScopedValue to propagate context across forked virtual threads.

Get The Most Out of Virtual Threads in Java 25: A Deep Dive by Christian Wörz