Inside Java

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/[email protected]/thread/Y72NRXM7KYBX43OKYBQMVKOZDWKG4MHS/ Angelos' mail re primitive patterns: https://mail.openjdk.org/archives/list/[email protected]/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/[email protected]/thread/SVHDNJDY62MX6YBEA4FSMW4U72H77F6S/ JDK 27 RC pushed back: https://mail.openjdk.org/archives/list/[email protected]/thread/EYKJPUAZ4BX4DXD7H4C5ETWJFNQZBFO5/ OpenJDK Mail Search: https://openjdk.barlasgarden.com/

While Java programs are deployed as bytecode, performance-relevant code will be compiled, at run time, to machine code whose performance rivals that of any other platform. In the HotSpot JVM, this is the job of the just-in-time compilers C1 and C2 and between speculation and traps, inlining and constant folding, escape analysis and scalar replacement (and many more), they apply a number of heuristics, analyses, and transformations to achieve that. This requires expertise, careful research, thorough testing, and regular reevaluations of old assumptions. In this "Ask the Architects" episode of the Inside Java Podcast, recorded during JavaOne 2026, Nicolai Parlog talks to Roberto Lozano, compiler engineer at the Java Platform Group at Oracle. In our show "Ask the Architects", we talk to experts in OpenJDK about their work on the Java language, API, and runtime.

In 2026, Java keeps evolving: Project Valhalla is gunning for merging its value types preview in the second half of this year; Babylon wants to incubate code reflection; Loom will probably finalize the structured concurrency API; Leyden plans to ship AOT code compilation; and Amber hopes to present JEPs on constant patterns and pattern assignments. And those are just the most progressed features - more are in the pipeline and discussed in this episode of the Inside Java Newscast.

In this special episode of the Inside Java Podcast, Nicolai Parlog talks to Adam Bien about scripting with Java, to Maurice Naftalin about the history and tradeoffs of the collections framework and erasure, and to Tom Cools about the innovative way the Belgian Java User Group organizes itself.