JBang - Unleash the Power of Java

Run any JAR or Java source file directly. JBang handles JDK downloads, dependency resolution, compilation, and caching so you can use the full Java ecosystem without the ceremony.

Get started

curl -Ls https://sh.jbang.dev | bash -s - app setup
jbang init --template=cli hello.java
jbang hello.java Max!

Or install via SDKMan (sdk install jbang), Homebrew (brew install jbangdev/tap/jbang), Chocolatey (choco install jbang), or Scoop (scoop install jbang).

See the installation docs for all options.

What JBang does

At its simplest, JBang runs JARs and Java source files directly from the command line. Point it at a GAV coordinate, a URL, or a local .java file and it takes care of the rest: downloading a JDK if needed, resolving dependencies, compiling, caching, and running.

For single-file programs you declare dependencies with //DEPS comments instead of a build file. That is enough to pull anything from Maven Central (or your own repos) and have it on the classpath.

JBang also works with .jsh (JShell), .kt (Kotlin), .groovy, and .md (Markdown with embedded Java).

Examples

Run any JAR from Maven Central by its GAV coordinate:

jbang com.github.lalyos:jfiglet:0.0.9 "Hello JBang!"

A plain Java file with a naked main (Java 25+):

///usr/bin/env jbang "$0" "$@" ; exit $?
//JAVA 25+

void main(String[] args) {
    System.out.println("Hello " + (args.length > 0 ? args[0] : "World"));
}

A CLI app with a dependency pulled from Maven Central:

///usr/bin/env jbang "$0" "$@" ; exit $?
//DEPS info.picocli:picocli:4.6.3
//JAVA 25+

import picocli.CommandLine;
import picocli.CommandLine.Command;
import picocli.CommandLine.Parameters;

@Command(name = "hello", mixinStandardHelpOptions = true)
class hello implements Runnable {
    @Parameters(index = "0", description = "The greeting to print")
    private String greeting;

    void main(String[] args) {
        new CommandLine(new hello()).execute(args);
    }

    public void run() {
        System.out.println("Hello " + greeting);
    }
}

A web server in a single file:

///usr/bin/env jbang "$0" "$@" ; exit $?
//DEPS io.javalin:javalin:7.1.0
//DEPS org.slf4j:slf4j-simple:2.0.17
//JAVA 25+

import io.javalin.Javalin;

void main() {
    Javalin.create(config -> {
        config.useVirtualThreads = true;
        config.router.mount(router -> {
            router.get("/", ctx -> ctx.result("Hello from JBang!"));
        });
    }).start(8000);
}

What else you can do

jbang edit myapp.java              # Open in IDE with full IntelliSense
jbang --debug myapp.java           # Run with debug port open for your IDE
jbang --native myapp.java          # Compile to native binary via GraalVM
jbang app install myapp.java       # Install as a system command
jbang export maven myapp.java      # Export to a Maven project
jbang alias add myapp myapp.java   # Create a short alias
jbang https://gist.github.com/...  # Run scripts from URLs

App Store

JBang can run any Java application packaged as a JAR. The App Store has community-contributed scripts and tools you can run directly.

Documentation

Full user documentation is at jbang.dev/documentation.

There is also an AI-generated technical reference at deepwiki.com/jbangdev/jbang built from the source code.

Community

• Zulip chat

• GitHub Issues

• Example scripts

• App Store

Contributing

Contributions are welcome. See CONTRIBUTING.adoc for details.

Thanks

JBang was inspired by kscript by Holger Brandl.

JBang is a Commonhaus Foundation project, released under the MIT License.