This API beforehand was incubated in JDK 16 by JDK 23. It will be re-incubated in JDK 24 with no API adjustments and no substantial implementations relative to JDK 23. Targets of the proposal embrace clearly and concisely expressing a variety of vector computations in an API that’s platform-agnostic, that gives dependable runtime compilation and efficiency on x64 and AArch54 architectures, that degrades gracefully and nonetheless capabilities when a vector computation can’t be expressed at runtime, and that aligns with Mission Valhalla, leveraging enhancements to the Java object mannequin.
The primary JDK 24-targeted characteristic, formally known as “Put together to Limit the Use of JNI,” requires issuing warnings about makes use of of JNI and adjusting the international operate and reminiscence (FFM) API, featured in JDK 22, to concern warnings in a constant method. These warnings are supposed to arrange for a future launch that ensures integrity by default by uniformly proscribing JNI and the FFM API. Targets of the plan embrace preserving JNI as an ordinary strategy to interoperate with native code, making ready the Java ecosystem for future releases that disallow interoperation with native code by default, and aligning the usage of JNI and the FFM API so library maintainers can migrate from one to the opposite with out requiring builders to alter command-line choices.
The second characteristic, late barrier enlargement for the G1 rubbish collector, is meant to simplify the implementation of G1’s boundaries. The G1 rubbish collector’s boundaries document details about software reminiscence accesses, by shifting their enlargement from early within the C2 compilation pipeline to later. Targets embrace lowering the execution time of C2 compilation when utilizing the G1 collector, making G1 boundaries understandable to HotSpot builders who lack a deep understanding of C2, and guaranteeing that C2 preserves invariants concerning the relative ordering of reminiscence accesses, safepoints, and boundaries. A fourth characteristic is preserving the standard of C2-generated JIT (just-in-time)-compiled code, by way of pace and measurement.