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samskivert Allow thread pool to be sized with -Dthread_pool_size.
Also use num processors minus one instead of num processors.
Latest commit 0f5622d Oct 3, 2018

What is it?

Getdown (yes, it's the funky stuff) aims to provide a system for downloading and installing a collection of files on a user's machine and upgrading those files as needed. Though just any collection of files would do, Getdown is mainly intended for the distribution and maintenance of the collection of files that make up a Java application.

It was designed as a replacement for Java Web Start due to limitations in Java Web Start's architecture which are outlined in the rationale section.

How do I use it?

A tutorial and more detailed specification are available from the Documentation page. Questions can be posted to the OOO Libs Google group.

How does it work?

The main design and operation of Getdown is detailed on the design page. You can also browse the javadoc documentation and source code if you're interested in implementation details.

Where can I see it in action?

Getdown was originally written by developers at OOO for the deployment of their Java-based massively multiplayer games. Try out any of the following games to see it in action:

Getdown is implemented in Java, but certainly can be used to deploy non-Java-based applications. Doing so would be a little crazy since you may have to install a JVM on the user's machine (if they don't already have one installed), which is a ~7MB download. This isn't so bad if you're already installing a Java application and must have a JVM, but it's a little crazy if the JVM is only used for your installer. It is probably possible to compile Getdown with GCJ, which would make Getdown a viable choice for non-Java applications.

Release notes

See for release notes.

Obtaining Getdown

The latest version of Getdown can be obtained thusly:

  • Download the pre-built jar file from Maven Central: getdown-1.7.1.jar
  • Obtain the jar artifact via Maven with the following identifier: com.threerings:getdown:1.7.1.
  • Check out the code and build it yourself.

You can also:

JVM Version Requirements

  • Getdown version 1.7.x requires Java 7 VM or newer.
  • Getdown version 1.6.x requires Java 6 VM or newer.
  • Getdown version 1.5 and earlier requires Java 5 VM or newer.


Getdown is built with Maven in the standard ways. Invoke the following commands, for fun and profit:

% mvn compile  # builds the classes
% mvn test     # builds and runs the unit tests
% mvn package  # builds and creates jar file
% mvn install  # builds, jars and installs in your local Maven repository


Feel free to pop over to the OOO Libs Google Group to ask questions and get (and give) answers.