Inside Java

Java projects that want to reduce their launch times need to look into Java's new ahead-of-time capabilities. A training run is used to populate a cache that, in production, allows the JVM to short-circuit many operations, like class loading and linking, profile gathering, and - probably soon - JIT compilation. To get the most out this feature, a good training run is essential. Netflix approach is pretty much the ideal one: use a canary deployment of a new version to collect training data and create the cache for the remaining deployments from that. But, from time scales to checkpointing, from managing to inspecting cache files, there are a number of details to consider.
In this "Input/Output" episode of the Inside Java Podcast, recorded during JavaOne 2026, Nicolai Parlog talks to Martin Chalupa, Senior Performance Engineer at Netflix and John Rose, JVM Architect at Oracle and Lead of OpenJDK's Project Leyden.
"Input/Output" is our new show, where we talk to people outside of OpenJDK to bring you their perspectives and insights into what's happening in the Java ecosystem. This special episode comes with an OpenJDK architect to boot.
Show notes:
JDK 27: https://jdk.java.net/27
Project Leyden: https://openjdk.org/projects/leyden/
Martin's talk at JavaOne 2026: https://www.youtube.com/watch?v=4kEh8hxAP4U

Java 27 is heading for release on September 15th. As with every release of the JDK there are a host of changes that will impact developers, from new features, to changes in behavior of existing features. In this episode of the Inside Java Newscast we will be "declassifying" all the developer impacting changes in Java 27.

OpenJDK's Project Valhalla is improving Java's support for custom numerical types. That goes beyond value types and also encompasses explorations into operator support. While Java is extremely unlikely to ever allow arbitrary operator definitions, it may well support limited operator overloading, so custom value types could be added or multiplied with plus or multiplication signs instead of annoying method calls.
In this "Ask the Architects" episode of the Inside Java Podcast, recorded during JavaOne 2026, Nicolai Parlog talks to Joe Darcy, Valhalla committer in the Java Platform Group at Oracle.
"Ask the Architects" is our podcast show, where we talk to experts in OpenJDK about their work on the Java language, API, and runtime.

JEP 540 proposes to incubate a simple JSON API and is currently proposed to target JDK 28. The pull request for Project Valhalla's JEPs 401 and 539 were merged and value types are available as a preview feature in the latest JDK 28 early-access builds. Oracle plans to backport post-quantum cryptography to Oracle JDKs with LTS (25, 21, 17, 11, and 8) and move Java to monthly security updated (currently quarterly).
JDK 28 EA builds: https://jdk.java.net/28/
Dan's mail re values: https://mail.openjdk.org/archives/list/core-libs-dev@openjdk.org/thread/Y72NRXM7KYBX43OKYBQMVKOZDWKG4MHS/
Angelos' mail re primitive patterns: https://mail.openjdk.org/archives/list/amber-spec-experts@openjdk.org/thread/WSXW4QMJ3EBIHIULEB25HUAMR5JB767H/
JEP 540: https://openjdk.org/jeps/540
JEP 496: https://openjdk.org/jeps/496
JEP 497: https://openjdk.org/jeps/497
JEP 572: https://openjdk.org/jeps/572
Blog post in PQC in LTS: https://blogs.oracle.com/java/post-quantum-cryptography-in-long-term-support-jdk-releases
Accelerated Vulnerability Detection and Response: https://blogs.oracle.com/security/accelerating-vulnerability-detection-and-response-at-oracle
More frequent Oracle JDK releases:  https://blogs.oracle.com/java/transitioning-java-to-more-frequent-security-updates
More Frequent OpenJDK releases: https://mail.openjdk.org/archives/list/jdk-updates-dev@openjdk.org/thread/SVHDNJDY62MX6YBEA4FSMW4U72H77F6S/
JDK 27 RC pushed back: https://mail.openjdk.org/archives/list/jdk-dev@openjdk.org/thread/EYKJPUAZ4BX4DXD7H4C5ETWJFNQZBFO5/
OpenJDK Mail Search: https://openjdk.barlasgarden.com/