Introduction

Package JVM applications into self-contained binaries. No JVM installation required to run the output.

What is jbundle?

jbundle transforms JVM applications (Clojure, Java, Kotlin, Scala, Groovy) into self-contained binaries. Think of it as the Go/Rust distribution experience for the JVM world.

# Build your app
jbundle build --input ./my-app --output ./dist/my-app

# Run anywhere (no Java required)
./dist/my-app

Why jbundle?

The conventional deployment approach requires both a JAR and a JVM on the target machine. GraalVM native-image is an alternative, but presents challenges: slow compilations, complex reflection configuration, and library incompatibilities.

jbundle offers a practical solution: bundle a minimal JVM runtime with your uberjar into a single executable. The result is a single file, no external dependencies, with full JVM compatibility.

Key Features

Feature	Description
Single binary	One file to distribute, like Go or Rust
No JVM required	Runtime is bundled inside the binary
Fast startup	AppCDS + profiles achieve ~200-350ms startup
Full compatibility	Everything that works on JVM works here
Multiple languages	Clojure, Java, Kotlin, Scala, Groovy
Smart caching	Layers cached independently by content hash

How It Works

detect → build uberjar → download JDK → jdeps → jlink → pack

1. Detect — Identifies your build system (deps.edn, project.clj, pom.xml, build.gradle)

2. Build — Runs the appropriate build command to create an uberjar

3. Download JDK — Fetches JDK from Adoptium (cached locally)

4. Analyze — Uses jdeps to detect required modules

5. Minimize — Creates minimal runtime with jlink (~30-50 MB)

6. Package — Bundles everything into a single executable

Quick Comparison

Aspect	jbundle	GraalVM native-image
Compatibility	100% JVM compatible	Requires reflection config
Build time	Fast	Slow (AOT compilation)
Startup	~200-350ms (AppCDS)	~10-50ms
Setup	Just jbundle	GraalVM + native-image + config

Next Steps

• Installation — Get jbundle on your system

• Quick Start — Build your first binary

• Configuration — Customize with jbundle.toml