What’s New?

October 2025: Check out the latest early-access build implementing value classes and objects! We encourage Java developers to try it out on their real-world applications and report their experiences.

To get started, you can review this short introduction at inside.java. Learn more with a presentation by Frederic Parain about the JVM optimizations applied to value objects.

New Features

The anticipated Valhalla language and performance features will not be delivered all at once, but through a steady stream of enhancements across multiple JDK releases.

There are five distinct feature sets under development:

1. Value Classes and Objects, introducing objects that lack identity and thus can have optimized encodings

2. Null Checking at both compile time and run time to manage the flow of null references through programs

3. Array Enhancements to support properties like immutability and safe initialization, and to facilitate interop between primitive and reference arrays

4. Unifying Primitives and Classes by improving the use of boxing for method invocations and generics, and by expanding features like conversions and operators to work with value classes

5. Parametric JVM, specializing and optimizing generic class and method parameterizations at run time

Background Documents & Presentations

These documents and presentations provide a more holistic view of the Valhalla project’s goals and design considerations.

• Frederic Parain: Value Classes & Heap Flattening (JVM Language Summit 2025)

• Brian Goetz: Growing the Java Language (JVM Language Summit 2025)

• Dan Smith: A New Model for Java Object Initialization (JavaOne 2025)

• Brian Goetz: Valhalla—Where Are We? (JVM Language Summit 2024)

• Dan Smith: Value Objects in Valhalla (JVM Language Summit 2023)

• The State of Valhalla (December 2021)
  • 1. The Road to Valhalla
  • 2. The Language Model
  • 3. The JVM Model
• Parametric JVM
  • Background: How We Got the Generics We Have (June 2020)
  • The Saga of the Parametric VM (April 2021)

Implementation

Development takes place in a public OpenJDK repository, with occasional early-access builds being published.

Interested developers are encouraged to experiment with these early releases.

• Early-Access Builds
• GitHub repository

Branches in the repository include lworld (the main line of Valhalla development), master (tracking main-line OpenJDK), and various others prototyping proposed features.

Project JEPs

Each enhancement to the Java platform is described and tracked with a JDK Enhancement Proposal (JEP). The following JEPs are under active development or have been delivered.

Legacy Links

See the legacy page for links to earlier proposed JEPs, design documents, presentations, and prototypes.