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Start GraalVM with access to NodeJS modules from Java/Kotlin

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NodeJVM

This tool starts up GraalVM in a way that gives you access to a genuine NodeJS instance. GraalVM is a variant of OpenJDK with a fast, modern JavaScript engine capable of running all NodeJS modules. GraalVM gives you a version of NodeJS that can access Java classes, but what if you want the other way around - Java code accessing NodeJS modules?

NodeJVM is a thin wrapper script and JAR that sets up the JVM with full access to NodeJS. It provides a simple API for calling in and out of the Node event loop thread, in a thread-safe way. It also provides a Kotlin API that offers many conveniences.

Note: NodeJVM is not a new JVM. It's just a way to start up GraalVM, which is a JVM produced by Oracle with a set of patches on top of OpenJDK.

Why use NPM modules from Java?

  • Gain access to unique JavaScript modules, like the DAT peer to peer file sharing framework shown in the sample.
  • Combine your existing NodeJS and Java servers together, eliminating the overheads of REST, serialisation, two separate virtual machines. Simplify your microservices architecture into being a polyglot architecture instead.
  • Use it to start porting NodeJS apps to the JVM world and languages, incrementally, one chunk at a time, whilst always having a runnable app.

Documentation

📚 Access the documentation site

What does it look like?

IntelliJ Ultimate edition users can get integrated "language injection", in which a single editor tab can use syntax highlighting/code completion/refactoring support from multiple languages simultaneously. Combined with Kotlin's multi-line string syntax, it looks like this:

Screenshot of language injection

TODO

  • Gradle plugin?
  • Windows support when GraalVM has caught up.
  • Can node_modules directories be packaged as JARs?

License

Apache 2.0