How to Effectively Restructure a Maven Multi-Module Project?

What are the best practices for restructuring a Maven multi-module project?

Restructuring a Maven multi-module project can greatly enhance the organization, maintainability, and scalability of your codebase. By following best practices and understanding the Maven project structure, you can achieve a more efficient setup that facilitates easier dependency management, build processes, and modularization.

<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 http://maven.apache.org/xsd/maven-4.0.0.xsd'>
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.example</groupId>
    <artifactId>parent-project</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>pom</packaging>
    <modules>
        <module>module-a</module>
        <module>module-b</module>
    </modules>
</project>

Causes

• Outdated project structure that doesn't reflect current requirements.
• Difficulty in managing dependencies.
• Lack of modularization leading to a monolithic approach.

Solutions

• Identify logical modules based on functionality or business domain.
• Create a new parent `pom.xml` to encapsulate all modules.
• Define module-specific `pom.xml` files to manage dependencies.
• Leverage Maven archetypes to generate new modules as needed.
• Regularly update project structure to align with evolving application needs.

Mistake: Not maintaining proper versioning of modules leading to dependency conflicts.

Solution: Use a consistent versioning strategy across modules, possibly utilizing Maven's properties.

Mistake: Creating too many modules, increasing complexity without need.

Solution: Only create modules that encapsulate distinct areas of functionality or responsibilities.

Mistake: Neglecting to update the parent `pom.xml` after adding or removing modules.

Solution: Regularly review and refine the parent `pom.xml` to keep it coherent with the current structure.