Build Multiple Independent Projects with Maven

<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0
            https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>org.codehaus.mojo</groupId>
    <artifactId>project-all-build</artifactId>
    <version>2.0</version>
    <packaging>pom</packaging>

    <modules>

        <!-- folder is a dir inside my project (root) dir -->
        <!-- this pom should be at root level to see all the subfolders -->
        <module>folder/project-dir-root</module>

        <!-- dir graph -->

        <!--

        - projects (root)
        |
        |_______ java
        |       |
        |       |______ hello_world
        |       |______ jpa
        |
        |_______ java-1
        |       |
        |       |_____ arraylist_sample
        |
        |_______ pom.xml

        -->

        <!-- maven builds the project in the following order -->

        <module>java/hello_world</module>

        <module>java-1/arraylist_sample</module>

        <module>java/jpa</module>


    </modules>
</project>