Project Valhalla, Explained: How a Decade of Work Arrives in JDK 28
Scored daily by a customisable AI persona to surface the most relevant engineering leadership news.
Project Valhalla deep dive in JDK 28 is highly technical, novel, and directly relevant to JVM and platform engineering.
Project Valhalla's JEP 401 (Value Classes and Objects) has been integrated into OpenJDK targeting JDK 28, adding over 197,000 lines across 1,816 files. The feature, disabled by default and in preview, allows user-defined classes to behave with the memory efficiency of primitives—eliminating pointer indirection, object headers, and heap fragmentation for dense, cache-friendly layouts. Brian Goetz cautions this is only the first part, with the community already shifting from 'they'll never ship it' to 'they didn't ship the most important part.'
Artur Skowronski — Head of Java / Kotlin Engineering at VirtusLab