Quarkus Meets Leyden at the JVM Performance Edge

Project Leyden raises a hard question for Quarkus: can we benefit from faster JVM startup and warm-up without undoing the assumptions that make Quarkus fast today? After years of optimizations to reduce startup costs, profiling JVM Quarkus applications still points to familiar hotspots: class loading and reading from JAR files.

Quarkus has already pushed hard in these areas through build-time processing, custom packaging, and class loading strategies. Leyden promises a major shift for JVM applications, but combining it with Quarkus is not just about enabling a new feature. Some of Leyden’s current constraints interact directly with optimizations Quarkus relies on, forcing us to question where responsibilities should sit between the framework, the JVM, and the application packaging model.

This talk shares findings from experimenting with Project Leyden inside Quarkus, and you will learn what to watch for when fine-tuning startup and warm-up behavior, and how to reason about the trade-offs between Quarkus’ existing optimizations and Leyden’s emerging JVM-level capabilities. Expect concrete findings, performance observations, current limitations, experimental prototypes, and practical lessons for developers who want to prepare their Quarkus applications for the next generation of JVM startup optimization.