The latest feature to be added, primitive types in patterns, instanceof, and switch, is intended to enhance pattern matching by allowing primitive types in all pattern contexts, and to extend instanceof and switch to work with all primitive types. Now in a fourth preview, this feature was previously previewed in JDK 23, JDK 24, and JDK 25. The goals include enabling uniform data exploration by allowing type patterns for all types, aligning type patterns with instanceof and aligning instanceof with safe casting, and allowing pattern matching to use primitive types in both nested and top-level pattern contexts. Changes in this fourth preview include enhancing the definition of unconditional exactness and applying tighter dominance checks in switch constructs. The changes enable the compiler to identify a wider range of coding errors.
With ahead-of-time object caching, the HotSpot JVM would gain improved startup and warmup times, so it can be used with any garbage collector including the low-latency Z Garbage Collector (ZGC). This would be done by making it possible to load cached Java objects sequentially into memory from a neutral, GC-agnostic format, rather than mapping them directly into memory in a GC-specific format. Goals of this feature include allowing all garbage collectors to work smoothly with the AOT (ahead of time) cache introduced by Project Leyden, separating AOT cache from GC implementation details, and ensuring that use of the AOT cache does not materially impact startup time, relative to previous releases.
The eleventh incubation of the Vector API introduces an API to express vector computations that reliably compile at run time to optimal vector instructions on supported CPUs. This achieves performance superior to equivalent scalar computations. The incubating Vector API dates back to JDK 16, which arrived in March 2021. The API is intended to be clear and concise, to be platform-agnostic, to have reliable compilation and performance on x64 and AArch64 CPUs, and to offer graceful degradation. The long-term goal of the Vector API is to leverage Project Valhalla enhancements to the Java object model.
