How to Identify and Manage Multiple Versions of the Same Dependency in Maven?

How can I detect and manage multiple versions of the same dependency in Maven?

<dependencies>
    <dependency>
        <groupId>com.example</groupId>
        <artifactId>example-artifact</artifactId>
        <version>1.0.0</version>
    </dependency>
    <dependency>
        <groupId>com.example</groupId>
        <artifactId>example-artifact</artifactId>
        <version>2.0.0</version>
    </dependency>
</dependencies>

In Maven projects, it's critical to manage dependencies effectively, especially when dealing with multiple versions of the same dependency. This can lead to 'jar hell' where conflicts occur, causing runtime issues. This guide outlines methods to detect and resolve such conflicts to ensure stable project builds.

<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>com.example</groupId>
            <artifactId>example-artifact</artifactId>
            <version>2.0.0</version>
            <scope>compile</scope>
        </dependency>
    </dependencies>
</dependencyManagement>

Causes

• Transitive dependencies: When dependencies rely on other libraries that may pull in different versions of the same dependency.
• Direct dependencies: Explicitly including different versions of the same library in your project's POM file.

Solutions

• Use the 'mvn dependency:tree' command to visualize the dependency tree and spot multiple versions.
• Implement the 'dependencyManagement' section in the POM file for consistent versions across modules.
• Utilize the 'exclude' tag to prevent specific dependency versions from being included.

Mistake: Not using dependencyManagement to control versions across modules.

Solution: Use the dependencyManagement section to enforce a single version throughout your project.

Mistake: Ignoring warnings about conflicting dependencies during build.

Solution: Always resolve dependency conflicts as indicated by Maven warnings to avoid potential runtime exceptions.