A Complete Guide on Maven Lifecycle

Maven is a build automation tool for Java projects. It streamlines dependency management, code compilation, testing, and packaging while ensuring consistency across teams.

This article provides an in-depth understanding of the Maven lifecycle, its key phases, Maven goals and plugins, and more.

What is Maven Lifecycle

The Maven lifecycle is a core concept in software development using Maven. It provides a structured and standardized sequence of steps for building, testing, and deploying projects. It defines how tasks (goals) are executed to automate and simplify the build process.

• Maven organizes the build process into lifecycles, consisting of multiple phases representing different stages of a project’s development.
• Each phase is responsible for tasks such as compiling code, running tests, or packaging artifacts.
• When a specific phase is executed, all preceding stages in the lifecycle are also executed in sequence.
• Tasks, also called goals, are executed using plugins, the core building blocks of Maven functionality.

Objectives of Maven

Maven is designed to help developers automate and manage the build lifecycle of Java-based projects.

The core objectives of Maven include:

• Automating and simplifying the build process
• Managing project dependencies and external libraries
• Enforcing a standardized project structure and lifecycle
• Providing consistent project information through metadata and reports
• Encouraging best practices in project management and development

Features of Maven

Maven provides several core features that support efficient project management and build automation. These features include:

• A consistent project structure and lifecycle for all builds
• Automatic dependency resolution, including transitive dependencies
• Multi-module project support for managing related components together
• Access to a central repository with updated libraries and metadata
• Predefined output formats such as JAR, WAR, and ZIP without custom scripting
• A plugin-based architecture that supports extensions in Java and scripting languages
• Minimal configuration needed to integrate new tools or features

Benefits of Maven Lifecycle

Below are the core benefits of Maven lifecycle:

• Consistency: Ensures all developers follow a standard build process.
• Automation: Reduces manual effort by automating repetitive tasks.
• Extensibility: Plugins allow adding custom goals for specific requirements.
• Reliability: Sequential execution prevents errors and ensures reliable results.
• Documentation: The site lifecycle generates detailed reports and documentation.

By following the Maven lifecycle, development teams can streamline their workflows and maintain a uniform, error-free build process.

Built-in Maven Lifecycles

The Maven lifecycle phases include: Clean, Default (Build), and Site. Each phase represents a specific stage in the build process.

1. Maven Clean Lifecycle

The Maven Clean Lifecycle phase ensures that a project is built from a clean state, eliminating any remnants from previous builds that might cause inconsistencies. It comprises three distinct phases: pre-clean, clean, and post-clean.​

Use the command mvn clean to invoke the Clean Lifecycle and run all its phases. This runs the pre-clean, clean, and post-clean phases to perform a full cleanup before the next build.

• Pre-Clean Phase: This initial phase is intended for tasks that should occur before the actual cleaning process begins. For example, it can back up existing build directories or notify the team that a clean operation is about to occur. By default, this phase does not perform any actions unless explicitly configured in the project’s pom.xml file.​

• Clean Phase: The core of the Clean Lifecycle involves deleting the project’s build output directory, typically the target directory. This action removes all files generated by the previous build, such as compiled classes, JAR/WAR files, and other artifacts. Executing this phase ensures that the next build starts without any leftover files that could lead to errors or inconsistencies.​
• Post-Clean Phase: Following the cleaning process, the post-clean phase is executed. This phase is suitable for tasks that need to occur after the cleaning, such as logging the completion of the clean operation or performing additional cleanup tasks not handled by the clean phase. Like the pre-clean phase, it does not perform any actions unless configured.​

2. Maven Build Lifecycle

The Maven Build Lifecycle consists of several phases, each representing a step in the build process. These Maven phases are executed in order, each serving a specific function in preparing the project for the next step.

• validate
  Ensures the project is correctly structured and all necessary information is available.
  Example: Checks for missing or invalid dependencies in the pom.xml.
  Why it’s important: If the project setup is incorrect, the build will not progress, saving time and avoiding downstream errors.
• initialize
  Initializes the build environment, setting up variables and configurations.
  Example: Defines project properties and sets up paths.
  Why it’s important: Prepares the necessary environment for the build to run smoothly.
• generate-sources
  Generates any source files needed for the build.
  Example: Generates code from annotations or templates.
  Why it’s important: Ensures all required source files are available before the compilation phase.
• process-sources
  Processes source files before compilation.
  Example: Performs code checks or formatting.
  Why it’s important: Ensures the source code is correctly prepared for the compilation stage.
• generate-resources
  Generates any resources needed by the project.
  Example: Generates configuration files, images, etc.
  Why it’s important: Ensures all necessary resources are available before processing and being included in the build.

• process-resources
  Copies and processes resources for inclusion in the build.
  Example: Copies properties files and other resources into the target directory.
  Why it’s important: Ensures that resources are available for use by the application and packaged correctly.
• compile
  Compiles the source code into bytecode.
  Example: Transforms .java files into .class files.
  Why it’s important: Converts the source code into executable bytecode that can be run on the Java Virtual Machine (JVM).
• process-classes
  Post-processes compiled classes.
  Example: Optimizes bytecode or applies transformations.
  Why it’s important: Ensures the compiled classes are in the correct format for the subsequent phases.
• generate-test-sources
  Generates any test code needed for the project.
  Example: Creates unit test files based on source code changes.
  Why it’s important: Ensures test code is available for the testing phase.
• process-test-sources
  Processes the test source code before compilation.
  Example: Validates or formats test files.
  Why it’s important: Prepares the test sources for compilation and execution.
• generate-test-resources
  Generates any additional resources required for testing.
  Example: Creates mock data or test configurations.
  Why it’s important: Ensures that all testing resources are available.
• process-test-resources
  Copies and processes resources required for testing.
  Example: Copies test configuration files into the target directory.
  Why it’s important: Ensures test resources are included and available during testing.
• test-compile
  Compiles the test code into bytecode.
  Example: Transforms test .java files into .class files.
  Why it’s important: Prepares the test code for execution during the testing phase.
• process-test-classes
  Post-processes compiled test classes.
  Example: Applies optimizations to test bytecode.
  Why it’s important: Ensures that test classes are ready for execution.
• test
  Runs the unit tests on the compiled code.
  Example: Executes tests using frameworks like JUnit.
  Why it’s important: Ensure the project functions correctly before moving to packaging.
• prepare-package
  Prepares the project for packaging.
  Example: Finalizes metadata and prepares the build output.
  Why it’s important: Prepares all necessary files for the final packaging step.
• package
  Packages the compiled code and resources into a distributable format (e.g., JAR, WAR).
  Example: Creates a .jar file for a Java application.
  Why it’s important: Generates the output artifact that will be deployed or shared.
• pre-integration-test
  Prepares for integration tests.
  Example: Initializes services or databases needed for integration tests.
  Why it’s important: Sets up the environment for integration testing, ensuring it’s properly configured.
• integration-test
  Runs integration tests to verify interactions between project components.
  Example: Tests database connections and external service interactions.
  Why it’s important: Validates that the components of the project work together as expected.

• post-integration-test
  Cleans up after integration tests.
  Example: Stops services or clears test data.
  Why it’s important: Ensures the test environment is properly cleaned after tests are complete.
• verify
  Verifies that the project is correctly built, including checking for errors.
  Example: Runs final checks on test results, code quality, and the build output.
  Why it’s important: Ensures the integrity of the project before deployment.
• install
  Installs the packaged artifact into the local repository.
  Example: Saves the built .jar file to the local Maven repository for reuse.
  Why it’s important: Make the artifact available for other projects or local testing.
• deploy
  Deploys the artifact to a remote repository for sharing with other developers or systems.
  Example: Uploads the .jar to a central repository like Nexus or Artifactory.
  Why it’s important: Makes the artifact available for integration in other projects or environments.

3. Maven Site Lifecycle

The Maven Site Lifecycle manages the project documentation’s generation, customization, and deployment. It includes four main Maven phases: pre-site, site, post-site, and deploy.

1. pre-site

This phase sets up the project environment before documentation is generated. It ensures that all required resources, tools, or configurations are ready before Maven builds the site.

Example: A custom plugin creates a directory structure for storing multilingual documentation or prepares static assets like logos or custom CSS files that will be included in the final site.

Why it’s important: Skipping this phase can result in missing resources or broken links in the final output. It ensures that everything needed for accurate and styled documentation is in place before site generation begins.

2. site

This is the primary phase that generates the documentation site using the Maven Site Plugin and other reporting plugins. It compiles reports, metrics, and structured content into HTML format.

Example:

Generates technical documentation such as:

• API references and method summaries
• Unit test summaries and pass/fail statistics
• Code structure and code coverage overviews
• Project metadata, including dependencies and licenses

Why it’s important: This phase provides a full snapshot of the project’s structure, quality, and health. Teams use it for audits, internal reviews, or external publication to inform users and contributors.

3. post-site

This phase runs after site generation and is used to finalize the output. It can include branding updates, injecting additional HTML or scripts, or packaging the site for deployment.

Example: A script adds organization-specific headers or injects analytics tracking code into the HTML files. It may also zip the site folder for later distribution.

Why it’s important: It allows teams to tailor the final output to organizational standards or deployment needs to ensure the site reflects the project’s branding and is technically ready for hosting.

4. deploy

This phase publishes the final site to a remote location, such as an Apache web server, GitHub Pages, or an internal documentation portal.

Example: The site:deploy goal pushes the generated site to a remote SCP location configured in the distributionManagement section of the pom.xml.

Why it’s important: Documentation is only helpful if it’s accessible. This phase ensures stakeholders can view the latest reports and information through a centralized, shareable location.

Package-Specific Lifecycles

While most projects follow the default lifecycle, certain packaging types trigger specialized workflows to meet the needs of that artifact type.

1. JAR (Java Archive)

JAR packaging creates a compressed archive that includes compiled Java classes and associated resource files. It is used to package Java libraries or standalone applications. This format allows easy reuse of Java code across different projects and is the default packaging type in Maven when none is specified.

For example, when you run mvn package on a project with JAR packaging, Maven creates a file like target/project-name.jar.

2. POM (Project Object Model)

POM packaging defines a project that does not generate a build artifact. Instead, it serves as a container for managing configurations, dependency declarations, and build logic across multiple child projects.

This type of project participates in the Maven lifecycle but skips the compilation and packaging phases. It is typically used in parent projects to centralize version management, plugin configurations, and dependency declarations.

For example, a project with <packaging>pom</packaging> may define shared dependency versions for several module projects in a multi-module setup.

3. Maven Plugin

Maven Plugin packaging is used to build custom Maven plugins that extend Maven’s capabilities. These plugins allow developers to add custom goals or Maven lifecycle phases to the build process. Projects with this packaging type follow a lifecycle focused on compiling plugin code, running tests, and packaging the plugin into a JAR file suitable for use in other Maven builds.

For example, a Maven plugin project will produce a .jar file containing the plugin logic, which can then be referenced in other Maven projects.

4. EJB (Enterprise JavaBean)

EJB packaging produces modules that contain business logic components for Java EE applications. These modules are deployed to enterprise servers that support the EJB specification, such as JBoss or GlassFish.

EJB projects use a lifecycle similar to the JAR lifecycle but apply EJB-specific metadata and structure. Maven compiles the classes and packages them into a .jar file suitable for deployment in a Java EE container.

For example, a project with EJB packaging creates an EJB module like target/module-name.jar that can be deployed to an application server.

5. WAR (Web Application Archive)

WAR packaging generates deployable web applications that include servlets, JSP files, HTML, JavaScript, and configuration files. This format is commonly used for applications deployed to servlet containers like Apache Tomcat.

Maven uses the standard build lifecycle with additional steps for assembling the web application’s directory structure. The final output is a .war file containing all necessary components for deployment.

For example, a WAR project will output target/project-name.war, containing compiled classes, static resources, and WEB-INF configuration.

6. EAR (Enterprise Archive)

EAR packaging produces enterprise applications that bundle multiple modules, such as EJBs and web applications, into a single deployable unit. It is typically used in large-scale Java EE systems.

The EAR lifecycle aggregates various .jar, .war, and other module files into a single .ear archive, maintaining the structure required for enterprise deployment.

For example, running mvn package on an EAR project will generate target/application.ear, which includes all submodules and resources configured in the project.

7. Other Packaging Types

Maven supports additional packaging types like zip, tar, or custom formats defined by plugins. These are used when a project requires a non-standard output or serves a special purpose outside typical Java artifact types.

These types may use default lifecycle phases or define custom ones via Maven plugins. The build process adapts to produce the specific archive or artifact required.

For example, a project with zip packaging may output target/archive.zip, which includes bundled assets or documentation files.

Role of POM in Maven Build Lifecycle

The POM (Project Object Model) file serves as the project’s configuration file and provides essential information for building, testing, and deploying the project.

Some key roles of the POM in the Maven build lifecycle  are:

1. Defines Project Structure and Dependencies

The POM file defines the project’s dependencies, which are external libraries or modules required to build the project. This ensures that all necessary libraries are available during compilation and runtime.

For example, if a Java project requires the Spring Core library, the dependency is specified in the POM as follows:

<dependencies>

  <dependency>

    <groupId>org.springframework</groupId>

    <artifactId>spring-core</artifactId>

    <version>5.3.8</version>

  </dependency>

</dependencies>

2. Coordinates Plugin and Goal Configuration

The POM file configures the necessary plugins and their goals to automate common build tasks such as compiling code, running tests, and packaging the project. These settings ensure the build process is automated and consistent.

For example, to compile Java code using JDK 1.8, the POM would configure the Maven Compiler Plugin as –

<build>

  <plugins>

    <plugin>

      <groupId>org.apache.maven.plugins</groupId>

      <artifactId>maven-compiler-plugin</artifactId>

      <version>3.8.1</version>

      <configuration>

        <source>1.8</source>

        <target>1.8</target>

      </configuration>

    </plugin>

  </plugins>

</build>

3. Manages Project Version and Build Information

The POM specifies the project’s version and other important metadata for building it. This helps ensure the correct version is built and used across different environments.

For example, a version is specified in the POM to distinguish between different releases of the project, as shown below –

<version>1.0.0</version>

4. Facilitates Inheritance and Dependency Management

The POM supports project inheritance, which allows child projects to inherit common configurations, reducing redundancy. This is particularly useful in multi-module projects, where many modules share the same configurations.

For example, if a parent project manages common dependencies or plugin versions, child projects can inherit these settings as seen below –

<parent>

  <groupId>com.example</groupId>

  <artifactId>parent-project</artifactId>

  <version>1.0</version>

</parent>

5. Specifies Build Phases and Profiles

The POM can define custom build phases and profiles that alter the build process based on the environment (e.g., development, production). This allows for flexibility and customizations tailored to different deployment needs.

For example, for a production environment, you can specify custom properties to ensure the code is compiled with the right settings, such as –

<profiles>

  <profile>

    <id>production</id>

    <properties>

      <maven.compiler.source>1.8</maven.compiler.source>

      <maven.compiler.target>1.8</maven.compiler.target>

    </properties>

  </profile>

</profiles>

Understanding Maven Goals and Plugins

In Maven, goals and plugins play a crucial role in executing specific tasks and extending the functionality of the build process.

Maven Goals

Goals are specific tasks that Maven can perform during the build lifecycle. Each phase of the lifecycle is associated with one or more goals. Maven provides default goals for each phase, but you can also define custom goals.

These goals can be executed from the command line using the mvn command followed by the goal name.

Examples of common Maven goals include compile, test, package, and install.

Maven Plugins

Plugins are the building blocks of Maven’s functionality. They provide implementations for various goals and can be used to extend the build process.

Maven has a vast ecosystem of plugins that cover a wide range of tasks and integrations.
Plugins can be configured in the project’s POM file, specifying the desired version and any custom configurations.

Maven resolves and downloads plugins from remote repositories when needed. Examples of popular Maven plugins include the Maven Compiler Plugin, Surefire Plugin for testing, and the Maven Assembly Plugin for creating custom distributions.

Benefits of Goals and Plugins

Here are the key benefits of Maven Goals and Plugins:

• Goals allow you to perform specific tasks within the build lifecycle, such as compiling code, running tests, packaging the project, or generating reports.
• Plugins provide additional functionality by implementing these goals and extending Maven’s capabilities.
• They help automate complex tasks, manage dependencies, generate documentation, and integrate with external tools.
• Goals and plugins ensure consistency across projects and facilitate collaboration by providing a standardized approach to building and managing projects.

In summary, Maven goals represent specific tasks within the build lifecycle, and plugins provide the implementations for those tasks.

Together, they allow you to automate various aspects of the build process, extend functionality, and achieve efficient and reliable project builds.

Common Maven Commands

Maven provides a set of core commands that support each project lifecycle phase. These commands handle tasks like compiling code, running tests, packaging artifacts, and deploying them to repositories.

Setting up a Maven project

Below are the steps to set up a Maven project:

Step 1: Install Java JDK

Install Java (JDK 1.7 or higher) on your machine. Java serves as the backbone for Maven, providing the necessary environment to bring your projects to life.

Step 2: Download Maven

Head over to the official Apache Maven website. Download the Maven binary zip file, unbox it, and let Maven dazzle you with its capabilities.

Step 3: Configure Maven’s Path

Set up the MAVEN_HOME environment variable, pointing it to Maven’s bin folder. This helps set up seamless communication between your system and Maven.

Step 4: Check if Maven is Installed properly

Know whether your Maven is installed correctly by checking its version. Open the command prompt, type the below command to know the version of Maven installed.

mvn -version

Step 5: Create a new Maven Project

Create a new project in Maven with the below command.

mvn archetype:generate

Maven will create a structure for your project.

Step 6: Add Maven Dependencies

To enrich your project’s capabilities, add dependencies to your project’s pom.xml file.

Step 7: Create a Maven Project

Maven will compile, test, and package your project using the below command.

mvn install

This command will build the Maven project and installs the project files ( JAR , WAR , pom. xml , etc.) to the local repository.

Launch your project after you complete the build.

Maven sets the stage for a smooth, organized, and efficient project management experience. Embrace its simplicity, and let Maven revolutionize your development journey.

Testing with Maven and BrowserStack Automate

Maven simplifies project management by handling dependencies and build processes, while BrowserStack provides a cloud-based platform to execute tests across a vast array of real devices and browsers. This ensures that applications are tested in environments that closely mirror real-world user conditions and enhances the reliability of test results.

Here are the key benefits of testing with Maven and BrowserStack Automate:

• Comprehensive Cross-Browser Testing: Run tests on over 3,500 real devices and browsers to ensure your application performs consistently across different platforms.
• Seamless CI/CD Integration: Add tests to your CI/CD workflows using tools like Jenkins, Azure DevOps, and GitLab to facilitate automated and continuous testing.
• Efficient Dependency Management: Use Maven’s pom.xml to manage Selenium and other testing dependencies so you can simplify project setup and maintenance.
• Parallel Testing: Run multiple tests simultaneously to reduce total execution time.
• Real-World Testing Environments: Test applications under real user conditions, such as different network speeds and device specifications, to identify issues that do not appear in simulated environments.

Talk to an Expert

Troubleshooting Common Issues During Maven Lifecycle

Maven can occasionally encounter issues during the build process. Addressing these issues will help ensure smoother Maven builds and better project management.

• Dependency Resolution Failures: Maven may not resolve dependencies if they’re missing from repositories or incorrectly defined. You can fix this by verifying that all dependencies in the pom.xml have valid groupId, artifactId, and version values and ensuring that required repositories are correctly configured.

• Compilation Errors: Syntax issues or missing imports in the source code can lead to failed compilation. To resolve this, review the compiler’s error output and correct issues in the code, and make sure all necessary dependencies are available.
• Plugin Not Found or Misconfigured: Build phases might fail if a required plugin is missing or misconfigured. Check that each required plugin is defined in pom.xml with the correct version and proper configuration parameters.
• JDK Version Mismatch: Maven may compile with an incompatible JDK version, causing compatibility problems. You can avoid this by aligning maven.compiler.source and maven.compiler.target with the JDK version used in your environment.
• Outdated or Deprecated Dependencies: Old dependencies may cause version conflicts or expose the project to bugs and vulnerabilities. Address this by regularly updating dependency versions and reviewing changelogs for breaking changes.
• Incorrect Project Configuration: Maven won’t execute correctly if the pom.xml contains invalid settings or structure. Ensure your pom.xml follows Maven’s schema and that elements like groupId, artifactId, packaging, and build configurations are all properly set.
• Resource Not Found During Build: Static resources might not get packaged if they’re located in the wrong directory. You can correct this by placing resources in the standard src/main/resources directory or updating the resource plugin configuration to match your custom structure.
• File Permission Denied Errors: Maven could fail to read, write, or delete files if system permissions are too restrictive. Ensure the Maven user can access the project directories and temporary files.
• Test Failures: Broken test logic or missing dependencies can cause tests to fail. Resolve this by analyzing test logs, debugging failed tests, and confirming that test dependencies are declared correctly in the pom.xml.

• Timeouts During Dependency Downloads: Slow or unstable network connections can interrupt downloads from Maven repositories. To fix this, improve your network reliability or adjust timeout settings in the .m2/settings.xml file. You can also download and install critical dependencies manually if needed.

Best Practice for Managing Maven Lifecycle

Following these best practices helps streamline the Maven build process, making it faster and more efficient.

• Skip Unnecessary Steps: You can speed up builds by skipping unnecessary parts of the lifecycle, such as tests during development. For example, to skip tests during a build, use mvn clean install -DskipTests.
• Build Only Required Modules: If your project has multiple modules, focus only on the ones you’re working on to save time. For example, to build only the core module in a multi-module project, use mvn -pl core install.
• Exclude Unneeded Modules: Avoid building modules not required for your current task. For example, to exclude the web module from the build process, use mvn install -pl !web.
• Use Parallel Builds: Building modules in parallel reduces total build time in multi-module projects. For example, to run builds with four threads, use mvn -T 4 install.

• Remove Unused Dependencies: Clean up your pom.xml by eliminating unnecessary dependencies to reduce build time and improve clarity. For example, unused libraries like log4j can be removed by deleting their entries from pom.xml.
• Run Maven Offline: You can avoid network access delays by building offline using cached dependencies. For example, to build using only locally cached dependencies, use mvn—o install.

Conclusion

Maven is widely used by prominent companies worldwide to streamline their software development processes. Companies like Apache Software Foundation, Google, Netflix, Twitter, LinkedIn, and PayPal rely on Maven for efficient build automation and dependency management.

Maven’s widespread adoption by these companies is a testament to its effectiveness in ensuring reliable and scalable software development. By leveraging Maven’s capabilities, these companies can manage dependencies, automate builds, and deliver high-quality software more efficiently.

Frequently Asked Questions

1. What are Maven builds?

Maven builds are the processes in which Maven compiles source code, runs tests, and packages the application.

2. What is the difference between Maven build and install?

In Maven, the build phase compiles and packages the application, while the install phase installs the built artifact into the local repository for use as a dependency in other projects.