How to Detect and Resolve Maven Dependency Conflicts Efficiently

Source: https://segmentfault.com/a/1190000017542396

1. What is a dependency conflict?

Maven is a powerful dependency management tool, but its mechanism can cause JAR conflicts. If two dependencies A and B both require library C in different versions (e.g., 1.0 and 2.0), Maven downloads both and selects one based on the shortest dependency path, leaving the other unused—this is a dependency conflict.

Usually the conflict does not break the system because Maven picks one version, but it can lead to ClassNotFound exceptions under certain conditions, so it is advisable to resolve conflicts.

2. How to resolve conflicts

The typical solution is to use Maven's <exclusion> element inside the <exclusions> section of a <dependency>. Example:

<dependency>
    <groupId>org.apache.logging.log4j</groupId>
    <artifactId>log4j-core</artifactId>
    <version>2.10.0</version>
    <exclusions>
        <exclusion>
            <artifactId>log4j-api</artifactId>
            <groupId>org.apache.logging.log4j</groupId>
        </exclusion>
    </exclusions>
</dependency>

In this example, log4j-core depends on log4j-api, but another module also brings in a different version of log4j-api. By adding the exclusion, Maven will not download the conflicting log4j-api version, ensuring only one version remains in the project.

3. Maven Helper plugin

The Maven Helper plugin for IntelliJ IDEA provides a Dependency Analyzer view that lists conflicting JARs. After installing the plugin, open pom.xml and click the “Dependency Analyzer” tab at the bottom.

Click the entry, locate the conflict, right‑click and choose Exclude to remove the unwanted version.

4. Additional tip

You can also use IntelliJ’s built‑in Maven Dependency Diagram (Ctrl+Alt+Shift+U) to visualize the dependency tree. Red solid lines indicate conflicts, while blue lines represent normal dependencies.