Oracle announces 'Project Detroit' to embed JavaScript engine V8 and Python runtime CPython into Java

Oracle announced Project Detroit as an OpenJDK project proposal at JavaOne 2026.

Detroit aims to embed V8 and CPython into Java to improve interoperability between Java, JavaScript, and Python.

The effort revives work that began in 2018 to embed a JavaScript engine, which was discontinued in 2019.

The implementation envisions embedding V8 and CPython source code into Java, keeping language compatibility while allowing each runtime to be maintained independently by its community.

Java and each runtime will run with separate heaps for security and be accessible via the Java ScriptEngineAPI; future support for other languages may be added, and GraalVM announced in September 2025 it would focus on other runtimes and may not keep up with Java versioning.