Quarkus 3.35 - JAR tree-shaking, PGO for native, Semeru AOT, @Transactional for Hibernate Reactive, and more

A new experimental quarkus.package.jar.tree-shake option enables build-time dependency tree-shaking. When set to classes, Quarkus performs bytecode reachability analysis to identify and exclude unused classes from runtime dependencies, reducing application JAR size.

The analysis traces references through supertypes, annotations, ServiceLoader entries, reflective class loading, and more.

As an example, running tree-shaking on the Quarkus CLI removes over 6,000 unreachable classes, saving around 18 MB (39.5%).

This feature supports fast-jar, uber-jar, legacy-jar, and aot-jar packaging types.

As mentioned, this new feature is experimental, and feedback is highly welcome!

You can now opt in to Profile-Guided Optimization (PGO) for native builds by setting quarkus.native.pgo.enabled=true.

Note that PGO is a feature of Oracle GraalVM and is not available in GraalVM Community Edition.

When enabled, Quarkus uses your integration tests as the workload to profile the application. The resulting PGO data is then fed into the native compilation for better runtime performance.

The implementation follows a similar pattern to the Project Leyden AOT support introduced in Quarkus 3.32.

Building on the Project Leyden AOT integration from Quarkus 3.32, Quarkus now also supports IBM Semeru’s AOT features.

In initial testing on the rest-json quickstart with IBM Semeru Runtime Open Edition 25, startup time was cut roughly in half (from ~380 ms down to ~190 ms).

For now, this is limited to building JARs with Semeru AOT, automatic container image building (as available with Leyden) is not yet supported.

Quarkus now supports the @Transactional annotation for Hibernate Reactive, thanks to a new quarkus-reactive-transactions extension.

This means you can use the familiar @Transactional annotation on methods that return Uni, and the transaction lifecycle (begin, commit, rollback) will be managed within the reactive pipeline.

A few things to keep in mind:

The management interface now has its own dedicated CORS configuration, allowing you to set CORS policies independently from the main HTTP interface.

The test infrastructure no longer uses System Properties to propagate configuration from Dev Services, Test Resources, and Test Profiles. This change opens the door for better parallel test execution (which we hope to achieve at some point in the future) and makes the Config system truly immutable.

Tests using QuarkusDevModeTest, QuarkusIntegrationTest, or QuarkusMainIntegrationTest can now declare a Config field or method parameter to access the updated configuration.

Quarkus snapshots are no longer published to Sonatype, which had reliability issues with the volume of artifacts involved. Snapshots are now published daily as GitHub Releases in the quarkusio/quarkus-ecosystem-ci repository, with version 999-SNAPSHOT. Each release contains a maven-repo.tar.gz asset with pre-built Maven artifacts that you can extract into your local Maven repository.

For CI setups, a dedicated GitHub Action is also available.

More details can be found in the Using snapshots section of the contributing guide.

We initially planned to make Jackson reflection-free serializers the default for Quarkus REST in 3.35. However, thanks to several community members who tested this feature and reported issues, we identified a number of edge cases that still need to be addressed. We decided to postpone making it the default to 3.36, so that we can fix these issues first.

We are very grateful to everyone who took the time to report problems, your feedback is what makes Quarkus better.

In the meantime, we very much welcome more testing from our community. You can enable reflection-free serializers by adding the following property to your configuration:

Please report any issues you encounter on GitHub.

Various Platform components were upgraded including: