Maven Central Repository

The Maven Central Repository is the default remote repository used by Maven to download project dependencies. It provides a centralized platform for accessing open-source libraries and artifacts. Developers can easily fetch and manage dependencies required for building Java applications.

Automatically downloads dependencies for projects
Supports version management and compatibility

Workflow of Maven Central Repository

Here is a diagram depicting how Maven Central Repository fits into the workflow of a Maven Project.

Explaination of Workflow:

Define Dependencies: Add required dependencies in pom.xml
Check Local Repository: Maven first looks for dependencies locally
Search Central Repository: If not found, Maven queries the central repository
Download Dependencies: Required artifacts are downloaded
Store Locally: Saved in local repository for future use
Build Project: Maven uses dependencies to compile and package the project

Step-by-Step Example of Maven Central Repository

Step 1: Create a Maven Project

Use Maven command or IDE to create a project.

mvn archetype:generate -DgroupId=com.app -DartifactId=mavencommends -DarchetypeArtifactId=maven-archetype-quickstart -DinteractiveMode=false

Step 2: Add Dependencies in `pom.xml`

The pom.xml which includes required project dependencies and project configuration.

XML

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="https://maven.apache.org/POM/4.0.0" xmlns:xsi="https://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="https://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>3.2.6</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.app</groupId>
    <artifactId>mavencommends</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>mavencommends</name>
    <description>Spring Reactive</description>
    <properties>
        <java.version>17</java.version>
    </properties>
    <profiles>
        <profile>
            <id>skip-tests</id>
            <properties>
                <maven.test.skip>true</maven.test.skip>
            </properties>
        </profile>
    </profiles>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

Step 3: Run Maven Build Command

Execute this command.

mvn clean install

Step 4: Dependency Resolution

Maven checks local repository (.m2 folder)
If not found -> downloads from Maven Central Repository

Step 5: Store in Local Repository

Downloaded dependencies are saved in:

~/.m2/repository

Step 6: Build and Run Project

Maven compiles and packages the project into a JAR/WAR
Application is ready to run