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TypeScript Java JavaScript

doppio: A JVM in TypeScript

doppio is a double shot of espresso. In this case it's also a JVM written in TypeScript.

To try doppio now, head to the live demo page.

To learn more, head to the doppio wiki, or read our academic paper (alt. link w/ no paywall) published at PLDI 2014!

You can also get in touch via our mailing list or via the IRC channel #plasma-umass on Freenode.

Integrating Into Your Site

Check out our Developer Guide for information on how you can integrate doppio into your website!

Getting & Building the Code

Before attempting to build doppio, you must have the following installed:

  • Node v0.10 or higher
  • NPM packages grunt-cli and bower installed globally
    • npm install -g grunt-cli bower
  • Java 8 JDK

If you are on Windows, you will need the following installed:

  • Git (must be on your PATH)
  • Python (must be on your PATH)
  • A version of Visual Studio

Run the following commands to build doppio. Note that your first time building may take some time, as the build script will download the entire Java Class Library.

git clone
cd doppio
npm install
bower install
grunt release      # For browser integration.
grunt release-cli  # For command-line use.


Run the full test suite using node.js:

grunt test

Run the full test suite in a web browser:

grunt test-browser

Run a specific test by invoking the test runner manually:

node build/dev-cli/console/test_runner.js classes/test/Strings

Command-line Usage

Run doppio with node.js (after grunt release-cli):

./doppio classes.demo.Fib 7
./doppio -jar my_application.jar
./doppio -cp my/class/path SomeClass

Automated Rebuilding

To automatically rebuild doppio while you modify files, run the following command:

grunt release watch

This will perform a complete build of doppio, and then will watch files to trigger partial rebuilds.

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