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Maven Project

Common Maven Commands

Apache Maven is one of the most popular build automation and dependency management tools in the Java ecosystem.
While Maven offers a wide range of commands, a handful of them are used daily by Java developers when building, testing, and managing projects.

In this lesson, we’ll cover the most common Maven commands:

  • mvn clean install
  • mvn package
  • mvn test
  • mvn dependency:tree

1. mvn clean install

This is probably the most widely used Maven command. It performs two significant steps:

  1. clean → Deletes the target/ directory from previous builds (removes compiled classes, JARs, reports, etc.).
  2. install → Compiles, tests, packages the project, and then installs the final artifact (JAR/WAR) into the local Maven repository (~/.m2/repository).

This makes the artifact available for reuse by other local Maven projects.

Example: 

mvn clean install

When to Use It?

  • Before deploying a project locally for use in other projects
  • In CI/CD pipelines, to ensure fresh builds without leftover files
  • When you want to test the full lifecycle: clean → compile → test → package → install

2. mvn package

The package command compiles source code, runs unit tests, and then packages the compiled code into a distributable format like:

  • .jar (Java Archive)
  • .war (Web Application Archive)
  • .ear (Enterprise Archive)

The packaged file will be placed inside the target/ folder.

Example

mvn package

When to use it?

  • When you only need to generate the final artifact (JAR/WAR) but don’t need to install it to the local repo
  • Helpful in creating build artifacts during development

3. mvn test

The test command runs all unit tests in the project using the Surefire Plugin by default.

  • Test classes are located in src/test/java
  • Test resources are in src/test/resources

Example

mvn test

When to Use It?

  • To verify your code changes are working before packaging or installing
  • As part of a CI pipeline for continuous testing
  • To ensure new features or bug fixes don’t break existing code
Tip: To skip tests, run: mvn install -DskipTests

4. mvn dependency:tree

This command shows a hierarchical view of dependencies in your project.
It helps developers:

  • See which libraries are included (direct and transitive dependencies)
  • Identify version conflicts
  • Debug dependency-related issues

Example:

mvn dependency:tree

Sample Output:

[INFO] com.example:my-app:jar:1.0-SNAPSHOT
[INFO] └─ org.springframework.boot:spring-boot-starter-web:jar:3.1.0:compile
[INFO]    ├─ org.springframework.boot:spring-boot-starter:jar:3.1.0:compile
[INFO]    ├─ org.springframework.boot:spring-boot:jar:3.1.0:compile
[INFO]    └─ com.fasterxml.jackson.core:jackson-databind:jar:2.15.2:compile

When to use it?

  • To debug dependency conflicts (multiple versions of the same library)
  • To optimize and remove unused dependencies
  • To understand transitive dependencies automatically added by Maven

Key Takeaways

  • mvn clean install → Cleans old builds and installs artifacts into the local repository
  • mvn package → Compiles and packages your project into JAR/WAR
  • mvn test → Runs unit tests with Surefire plugin
  • mvn dependency:tree → Shows dependencies and resolves conflicts

Mastering these commands will make you more efficient and help you build reliable Java applications with Maven.