Java 28 is beginning to take definitive shape. Set for release in March 2027 as a standard feature release, JDK 28 brings several substantial enhancements aimed at performance optimization, developer convenience, and modernized runtime behavior.

Here is an overview of the key proposals and features planned for the release.

Improved Startup Times via Ahead-of-Time (AOT) Compilation

A primary highlight proposed for JDK 28 is Ahead-of-Time (AOT) code compilation. Designed to significantly reduce initial warmup and application startup times, AOT compilation generates optimized native code ahead of launch.

When the Java Virtual Machine (JVM) boots up, this pre-compiled code is instantly available, allowing applications to:

• Reach peak performance much faster after startup.
• Maintain consistent throughput during workload spikes.
• Benefit from performance gains without requiring code modifications across applications, libraries, or frameworks.

5 Core Features Targeted for JDK 28

Alongside AOT compilation, five additional features are currently slated for this release:

1. Value Objects (Preview Feature)

Java is introducing immutable value objects that lack a traditional object identity. Instead of relying on memory addresses, equality operations (such as ==) evaluate value objects based strictly on the values of their fields. This allows the JVM to apply internal memory optimizations while providing developers with a robust programming model for immutable data.

2. Generational Mode for Shenandoah GC

The Shenandoah Garbage Collector is updating its operational defaults. Generational mode will now become the primary default, while non-generational mode is officially deprecated for future removal. This change consolidates development efforts around generational garbage collection and simplifies long-term GC maintenance.

3. Strictly-Initialized Fields (Preview Feature)

To enhance integrity guarantees, JDK 28 introduces strictly-initialized fields at the JVM level. These fields must be explicitly assigned prior to being read, eliminating scenarios where uninitialized defaults (such as null or 0) can be observed. Final fields declared under this rule will consistently return the same value throughout their lifecycle.

4. Native Simple JSON API (Incubator Feature)

To reduce reliance on third-party dependencies for standard data handling, Java is introducing a lightweight, built-in JSON API. The goal is to provide a standardized, zero-ceremony approach within the core JDK for parsing and generating JSON documents.

5. Native PEM Encodings for Cryptography

A new standard API will allow developers to encode cryptographic keys, certificates, and Certificate Revocation Lists (CRLs) directly into Privacy-Enhanced Mail (PEM) format, as well as decode PEM data back into Java cryptographic objects.

Deprecation & Lifecycle Updates

• Deprecation of macOS/x64 Port: Following Apple’s hardware transition to Apple Silicon (AArch64), maintenance for the macOS x86-64 architecture port ceased in JDK 27. In JDK 28, the macOS/x64 port is formally deprecated for removal in a future release.
• Release Model: Like its predecessor JDK 27, JDK 28 is a short-term, feature-oriented release (non-LTS) that will receive six months of primary support from Oracle.