Get Maven dependencies locations without any effort

With Apache Maven, it is quite common to have to reference dependency location and not just its coordinates. The most common and known examples are:

• For javaagents (-javaagent:/path/to/agent.jar)
• For application specific usage (-Dapp.extensions=/path/config.jar)
• For test environment (for instance in arquillian.xml you will point to a container zip)
• Etc...

The solution I saw the most often was to use the local repository path. It ends up on configurations looking like:

-javaagent:${settings.localRepository}/my/groupId/artifactId/version/artifactId-version.jar

With very simple groupId and properties for the artifactId and version it is not that bad but often the groupIds are long and it ends up on a very long line not readable and with duplication which is quite error prone.

The alternative I like to use is to rely on the maven dependency plugin to give me the location:

<plugin>
  <groupId>org.apache.maven.plugins</groupId>
  <artifactId>maven-dependency-plugin</artifactId>
  <version>3.1.1</version>
  <executions>
    <execution>
      <goals>
        <goal>properties</goal>
      </goals>
    </execution>
  </executions>
</plugin>

This will be enough to let the plugin to register in the project properties all the dependencies location under the key groupId:artifactId:type[:classifier].

For instance if you want the javaagent for Aspectj, add as dependency (even in scope test):

<dependency>
    <groupId>aspectj</groupId>
    <artifactId>aspectjweaver</artifactId>
    <version>1.5.4</version>
</dependency>

And then you can access the location of the weaver with the property ${aspectj:aspectjweaver:jar}. Back to our previous example we would now write:

-javaagent:${my.groupId:artifactId:jar}

Easier no? :)