Maven, a popular build automation and project management tool, supports the creation of multi-module projects. This approach allows you to break down a complex system into smaller, manageable modules. In this article, we will explore the configuration of a multi-module Maven project and understand how to structure the pom.xml files for effective modularization.

What is a Multi-Module Maven Project?

A multi-module Maven project is a project that consists of multiple modules, each represented by its own subdirectory and containing its own set of source code, resources, and configuration. Modules can have dependencies on each other, enabling better organization and separation of concerns in large-scale projects.

Structure of a Multi-Module Project

The structure of a multi-module project typically looks like the following:

• The root directory contains the main pom.xml file for the entire project.
• Each module has its own subdirectory, and within each module directory, there is a pom.xml file specific to that module.

Configuring the Root pom.xml

The root pom.xml file serves as the aggregator for all modules in the project. It specifies the modules to be included and may contain other configurations relevant to the entire project.

Here is a minimal example of a root pom.xml:

Explanation:

• The <modules> section lists all the modules to be included in the project.
• The <packaging> element is set to pom to indicate that this project is an aggregator.

Configuring Module pom.xml Files

Each module within the project has its own pom.xml file. This file contains module-specific configurations, dependencies, and build instructions.

Here’s an example of a module pom.xml:

Explanation:

• The <parent> section specifies the parent project, indicating that this module is part of a multi-module project.
• The <artifactId> element uniquely identifies the module within the project.

Building and Running Modules

To build the entire project, navigate to the root directory and execute:

This command will build and install all modules in the correct order, considering dependencies.

To build and run an individual module, navigate to the module directory and execute:

This will build and install the specific module.

Conclusion

Organizing a project into multiple modules with Maven provides several benefits, including better code organization, reusability, and maintainability. Understanding how to configure the pom.xml files for a multi-module project is crucial for effective development and collaboration. Use the provided examples as a starting point, and tailor them to suit the specific requirements of your project.