How to Detect and Clean Unused Maven Dependencies with mvn dependency:analyze

Why manage Maven dependencies?

In many Java backend projects, outdated or unnecessary JAR files increase build time, risk security vulnerabilities, and cause maintenance overhead. Regularly analyzing dependencies helps keep the project lean and secure, especially when supporting private‑cloud or client‑specific deployments.

How to analyze dependencies

Open a terminal in the project root or use IntelliJ IDEA’s built‑in Maven tool, then execute the following command: mvn dependency:analyze The plugin prints two warning sections: Used undeclared dependencies found and Unused declared dependencies found . Review each section carefully.

Used undeclared dependencies found

This warning indicates that the code references a library that is not declared directly in pom.xml. The library is usually pulled in transitively by another dependency. To fix the issue, add the missing JAR (e.g., B.jar) to the pom.xml so the dependency graph is explicit.

Unused declared dependencies found

This warning lists dependencies that are declared in pom.xml but not referenced in the source code under src/main/java or src/test/java. Removing these entries reduces the artifact size and eliminates potential attack surfaces. Before removal, back up the pom.xml and verify that the dependency is not required by configuration files or runtime extensions.

When to run the analysis

During new project initialization: choose only the necessary JARs instead of copying an old project's dependency list.

When refactoring feature code: combine refactoring with a dependency audit to catch unused libraries early.

Risks and precautions

The tool only scans Java source files; it may miss usages in XML, properties, or annotation processors.

Always back up pom.xml before deleting dependencies to avoid accidental breakage.

Because false positives can occur, run the full test suite after any change to confirm project stability.

Using IntelliJ IDEA

In IntelliJ, navigate to the directory containing pom.xml, right‑click the file, choose Maven → Analyze Dependencies, or use the Maven tool window. The IDE will display the same warnings in a graphical view, allowing you to add or remove dependencies directly.