Maven Lifecycle and Dependency Scope

About

Maven organizes the build process into well-defined phases, allowing structured execution of tasks like compilation, testing, packaging, and deployment.

Maven has three primary lifecycles:

• Clean: Removes previous build artifacts.

• Default (Build): Compiles, tests, packages, and deploys the project.

• Site: Generates documentation.

Among these, the default lifecycle consists of the following key phases:

Phase	Description
validate	Ensures the project is correct and necessary information is available.
compile	Compiles source code of the project.
test	Runs unit tests using a testing framework (e.g., JUnit, TestNG).
package	Bundles compiled code into a distributable format (JAR, WAR, etc.).
verify	Runs integration tests to ensure package correctness.
install	Installs the package in the local repository (~/.m2) for use by other projects.
deploy	Uploads the package to a remote repository for sharing with others.

Dependency Scope vs. Lifecycle Phases

Maven dependencies are activated based on their scope at different phases of the build lifecycle.

1. compile Phase

• Converts .java source files to .class bytecode.

• Dependencies in compile, provided, and system scope are available.

• test and runtime dependencies are not available.

Example:

mvn compile

Available Scopes: compile, provided, system Ignored Scopes: test, runtime

2. test Phase

• Executes unit tests using JUnit/TestNG.

• Requires compiled source code from compile phase.

• Dependencies in compile, provided, runtime, and test scopes are available.

Example:

mvn test

Available Scopes: compile, provided, runtime, test Ignored Scopes: system (not propagated)

Example pom.xml:

<dependency>
    <groupId>junit</groupId>
    <artifactId>junit</artifactId>
    <version>4.13.2</version>
    <scope>test</scope>
</dependency>

• JUnit is available only during test execution.

• It won't be included in the final JAR/WAR.

3. package Phase

• Packages compiled code into a JAR/WAR/ZIP.

• Dependencies in compile, runtime scope are included in the package.

• provided and test dependencies are not included.

Example:

mvn package

Available Scopes: compile, runtime Ignored Scopes: test, provided

4. verify Phase

• Runs integration tests to verify the packaged application.

• Often used with frameworks like Selenium, Cucumber, or REST Assured.

• Dependencies in compile, runtime, test scopes are available.

Example:

mvn verify

Available Scopes: compile, runtime, test Ignored Scopes: provided, system

5. install Phase

• Deploys the built JAR/WAR into the local Maven repository (~/.m2).

• Useful for sharing dependencies across local projects.

• Dependencies in compile, runtime scope are packaged.

Example:

mvn install

Available Scopes: compile, runtime Ignored Scopes: test, provided, system

6. deploy Phase

• Uploads the package to a remote repository (like Nexus, Artifactory, or Maven Central).

• Used in CI/CD pipelines for distributing artifacts.

• Dependencies in compile, runtime scope are deployed.

Example:

mvn deploy

Available Scopes: compile, runtime Ignored Scopes: test, provided, system