Configuring Maven

Configuring your Local Repository

The location of your local repository can be changed in your user configuration. The default value is ${user.home}/.m2/repository/.

<settings>
  ...
  <localRepository>/path/to/local/repo/</localRepository>
  ...
</settings>

Note: The local repository must be an absolute path.

Configuring a Proxy

Proxy configuration can also be specified in the settings file.

For more information, see the Guide to using a Proxy.

Configuring Parallel Artifact Resolution

By default, Maven 2.1.0+ will download up to 5 artifacts (from different groups) at once. To change the size of the thread pool, start Maven using -Dmaven.artifact.threads. For example, to only download single artifacts at a time:

mvn -Dmaven.artifact.threads=1 verify

You may wish to set this option permanently, in which case you can use the MAVEN_OPTS environment variable. For example:

export MAVEN_OPTS=-Dmaven.artifact.threads=3

Security and Deployment Settings

Repositories to deploy to are defined in a project in the <distributionManagement> section. However, you cannot put your username, password, or other security settings in that project. For that reason, you should add a server definition to your own settings with an id that matches that of the deployment repository in the project.

In addition, some repositories may require authorization to download from, so the corresponding settings can be specified in a server element in the same way.

Which settings are required will depend on the type of repository you are deploying to. As of the first release, only SCP deployments and file deployments are supported by default, so only the following SCP configuration is needed:

<settings>
  ...
  <servers>
    <server>
      <id>repo1</id>
      <username>repouser</username>
      <!-- other optional elements:
        <password>my_login_password</password>
        <privateKey>/path/to/identity</privateKey> (default is ~/.ssh/id_dsa)
        <passphrase>my_key_passphrase</passphrase>
      -->
    </server>
  ...
  </servers>
  ...
</settings>

To encrypt passwords in these sections, refer to Encryption Settings.

Using Mirrors for Repositories

Repositories can be declared inside a project, which means that if you have your own custom repositories, those sharing your project easily get the right settings out of the box. However, you may want to use an alternative mirror for a particular repository without changing the project files. Refer to Guide to Mirror Settings for more details.

Profiles

Repository configuration can also be put into a profile. You can have multiple profiles, with one set to active so that you can easily switch environments. Read more about profiles in Introduction to Build Profiles.

Optional configuration

Maven will work for most tasks with the above configuration, however if you have any environmental specific configuration outside of individual projects then you will need to configure settings. The following sections refer to what is available.