anshulraigh / maven

Maven

What is Maven?

• Maven is a build automation tool used primarily for Java projects.
• It addresses two aspects of building software: first, it describes how software is built, and second, it describes its dependencies.

Why Use Maven?

• Simplifies the build process: Maven uses a standardized project structure and a consistent build process.
• Dependency Management: Automatically downloads and manages project dependencies from central repositories.
• Reproducible Builds: Ensures consistent build results across different environments.
• Easy Integration: Works seamlessly with various IDEs and CI/CD tools.
• Extensibility: Can be extended with plugins to perform a variety of tasks.

Need for Maven

• Efficient Project Management: Organizes project structure and simplifies build lifecycle.
• Dependency Management: Handles dependencies, reducing conflicts and ensuring compatibility.
• Consistent Builds: Provides a standard way to build projects, ensuring consistency across development teams.
• Simplifies Project Configuration: Uses a simple XML file (pom.xml) to manage project configurations.
• Community Support: Extensive community and plugin support for various needs and integrations.

Maven Build Lifecycle Commands

1. clean

• Command: mvn clean
• Explanation: Removes all files generated by the previous build, ensuring a fresh start for the next build process.

2. validate

• Command: mvn validate
• Explanation: Checks if the project is correct and all necessary information is available. This phase ensures that the project is in a valid state before proceeding to the next phases.

3. compile

• Command: mvn compile
• Explanation: Compiles the source code of the project.

4. test

• Command: mvn test
• Explanation: Runs the tests using a suitable unit testing framework. The tests should be located in the src/test/java directory.

5. package

• Command: mvn package
• Explanation: Packages the compiled code into a distributable format, such as a JAR or WAR file.

6. verify

• Command: mvn verify
• Explanation: Runs any checks to verify the project is valid and meets quality standards.

7. install

• Command: mvn install
• Explanation: Installs the package into the local repository, making it available for other projects on the same machine.

8. deploy

• Command: mvn deploy
• Explanation: Copies the final package to the remote repository for sharing with other developers and projects.

Example Commands

• To clean and build the project: mvn clean install
• To compile and run tests: mvn compile test

pom.xml

The pom.xml file is the heart of a Maven project, managing dependencies, plugins, and project configurations.

Key Elements of pom.xml:

• groupId: Defines the group or organization that the project belongs to. It follows the standard Java package naming rules (e.g., com.example).
• artifactId: A unique name to identify the project (e.g., my-project).

Example pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>com.anshulmaventutorial</groupId>
  <artifactId>FirstMavenProject</artifactId>
  <version>1.0-SNAPSHOT</version>

  <name>FirstMavenProject</name>
  <url>http://www.example.com</url>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <maven.compiler.source>1.8</maven.compiler.source>
    <maven.compiler.target>1.8</maven.compiler.target>
  </properties>

  <dependencies>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.11</version>
      <scope>test</scope>
    </dependency>
  </dependencies>

  <build>
    <pluginManagement>
      <plugins>
        <plugin>
          <artifactId>maven-clean-plugin</artifactId>
          <version>3.1.0</version>
        </plugin>
        <plugin>
          <artifactId>maven-resources-plugin</artifactId>
          <version>3.0.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-compiler-plugin</artifactId>
          <version>3.8.0</version>
          <configuration>
            <source>1.8</source>
            <target>1.8</target>
          </configuration>
        </plugin>
        <plugin>
          <artifactId>maven-surefire-plugin</artifactId>
          <version>2.22.1</version>
        </plugin>
        <plugin>
          <artifactId>maven-jar-plugin</artifactId>
          <version>3.0.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-install-plugin</artifactId>
          <version>2.5.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-deploy-plugin</artifactId>
          <version>2.8.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-site-plugin</artifactId>
          <version>3.7.1</version>
        </plugin>
        <plugin>
          <artifactId>maven-project-info-reports-plugin</artifactId>
          <version>3.0.0</version>
        </plugin>
      </plugins>
    </pluginManagement>
  </build>
</project>