In-project Maven Repository (for private libs)

pom.xml

<!-- create "private_libs" as folder and put your private maven-dependencies there -->
<repositories>
    <!-- in project repository, mostly for private libs -->
    <repository>
        <id>in-project</id>
        <name>In Project Repo</name>
        <url>file://${project.basedir}/private_libs</url>
        <snapshots>
            <enabled>true</enabled>
            <updatePolicy>always</updatePolicy>
        </snapshots>
        <releases>
            <enabled>true</enabled>
            <updatePolicy>always</updatePolicy>
        </releases>
    </repository>
</repositories>

This is useful in cases you need to add (transitive) dependencies to your project without the need to expose too much of your infrastructure to the other party working with your projects.