Building Maven

Why would I want to build Maven?

Building Maven yourself is for one of two reasons:

  • to try out a bleeding edge feature or bugfix (issues can be found in JIRA),
  • to fix a problem you are having and submit a patch to the developers team.

Note, that you don't need to bootstrap Maven for day to day use, or to develop plugins. While we encourage getting involved and fixing bugs that you find, for day to day use we recommend using the latest release.

Checking out the sources

All of the source code for Maven and its related libraries is in managed in the ASF source code repositories. Current development of the core of Maven, and some other components, are in git. Other pieces (and older versions) are in Subversion. For details, see

To build Maven 3 (the current stable branch), you need the HEAD of the maven module. To check that out, run the command:

git clone maven

To build Maven 2, you need the maven-2.2.x branch. To check that out from a cloned repository, run the command:

git checkout maven-2.2.x

Other Modules

Other modules you might be interested in related to Maven development are:

  • maven-integration-testing - git clone
  • plugins/trunk - The sources of the Maven plugins. These can be individually installed, or built together.
  • plugin-tools/trunk - Set of tools for Maven plugins like test harness.
  • release/trunk - Release manager and plugin.
  • site/trunk - The Maven website.
  • skins/trunk - Skins for generated site used by site plugin.
  • Some Maven sub projects
    • wagon - Maven Wagon, used by the artifact code and others for providing the transport layer to get and put artifacts in a repository. git clone
    • scm - Maven SCM, a generic API to communicate with various different SCM providers, used by Continuum and the release and SCM plugins. git clone
    • doxia/trunk - The Doxia site generation library used by several report plugins and site plugin.
    • surefire/trunk - The Surefire test runner. git clone
  • shared/trunk - Collection of shared libraries like file/path handling.
  • sandbox/trunk - Sandbox codes.
  • Plexus - the IoC container used by Maven.

If you're looking at the trunks directory with ViewVC, there is seemingly nothing there. We use externals definitions to link together all the trunks into one logical location for convenience. If you want to see what is being linked into one logical location you can use the following command:

svn propget svn:externals

Building Maven

Building Maven With Maven Installed

If you already have Maven installed, it can be faster to build a new version with Maven, rather than a clean bootstrap.

To do this, run from the maven-3 or maven-2.2.x directory:

mvn install

Optionally, you can use the following to run the full (long) suite of integration tests; see below.

The assemblies will be created in apache-maven/target for Maven 2.0.x or maven-distribution for Maven 2.1, and can be unzipped to the location where you'd like Maven installed.

Running the full integration tests

Before checking in a change or submitting a patch, it's a good idea to run the integration tests. These live in their own directory in subversion, as noted above: core-integration-testing/trunk. Using your local build of Maven, run:

mvn install -Prun-its

Building Maven Without Maven Installed

If you do not have Maven installed, you can use Apache Ant to build Maven.

Once you have checked out the code, change into the maven-3 or maven-2.2.x directory that was created.

Set the M2_HOME environment variable to the location that should contain Maven. This directory must be named after the Maven version you want to build and install, for example /usr/local/maven-2.2-SNAPSHOT.

export M2_HOME=/usr/local/maven-2.2-SNAPSHOT


set M2_HOME=c:\maven-2.2-SNAPSHOT
set PATH=%M2_HOME%\bin;%PATH%

From this, run the ant command:


This will download dependencies, build Maven, and install it into the directory you specified as M2_HOME above.

If you have any problems or get any failures during the run, please report them to the Maven Developers List.

For more information, consult the project help in the Ant build file.

ant -projecthelp

The result is included here for convenience:

Buildfile: build.xml

    The first time you build Maven from source, you have to build Maven without
    Maven. This Ant script builds a minimal Maven, just enough to re-launch
    Maven again in this directory and generate an installation assembly. Then we
    extract the assembly and re-run the Maven build one more time, this time
    with the full generated Maven.

    To run this script, you must set the M2_HOME environment variable or the
    maven.home property to the location that should contain Maven. This
    directory *must* be named after the maven version you want to install, e.g.

    You can set the maven.repo.local property to specify a custom location for
    your local repository for the bootstrap process.

Main targets:

 classpath-pre     constructs a classpath reference containing our dependencies,
                   and verifies that all files are present

 clean-bootstrap   cleans up generated bootstrap classes

 compile-boot      compiles the bootstrap sources

 extract-assembly  extracts the maven assembly into maven.home

 generate-sources  generates Java sources from Modello mdo model files

 maven-assembly    generates the Maven installation assembly using the bootstrap

 maven-compile     compiles Maven using the bootstrap Maven, skipping automated

 pull              copies all required dependencies from the Maven remote
                   repository into your local repository.  Set the 'skip.pull'
                   property to skip this step, but only if you're sure you
                   already have all of the dependencies downloaded to
                   your local repository

 run-full-maven    runs the full extracted Maven, now with tests

Default target: all