Comprehensive Maven Guide: Repository Setup, Dependency Management, Multi‑Module Projects, and Plugin Configuration

1. Basic Configuration

Maven introduces the concept of repositories; developers publish JARs to a remote repository and Maven downloads them to the local repository when referenced, optionally using a private repository before falling back to the central one.

A minimal Maven project includes groupId , artifactId , and version elements.

<?xml version="1.0" encoding="UTF-8"?>
<project ...>
    <!-- fixed 4.0.0, specifies the POM model version -->
    <modelVersion>4.0.0</modelVersion>
    <groupId>xyz.ibudai</groupId>
    <artifactId>maven-demo</artifactId>
    <version>1.0.0‑SNAPSHOT</version>
    <description>This is maven demo.</description>
</project>

2. Dependency Management

2.1 Dependency Introduction

Dependencies are added via the dependencies tag.

<dependencies>
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql‑connector‑java</artifactId>
        <version>8.0.27</version>
        <scope>runtime</scope>
    </dependency>
</dependencies>

The scope element can be compile , provided , runtime , test , or system .

2.2 Transitive Dependencies

Maven resolves transitive dependencies automatically; only the direct dependency needs to be declared.

2.3 Dependency Exclusion

Conflicting versions can be excluded using the excludes tag.

<dependency>
    <groupId>xyz.ibudai</groupId>
    <artifactId>demo‑a</artifactId>
    <version>1.0.0</version>
    <excludes>
        <exclude>
            <groupId>xyz.ibudai</groupId>
            <artifactId>dependency‑b</artifactId>
            <version>1.0.0</version>
        </exclude>
    </excludes>
</dependency>

2.4 Variable Configuration

Version numbers can be centralized with properties and referenced via ${} .

<properties>
    <mysql.version>8.0.30</mysql.version>
    <junit.version>4.13.2</junit.version>
</properties>

<dependencies>
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql‑connector‑java</artifactId>
        <version>${mysql.version}</version>
    </dependency>
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>${junit.version}</version>
    </dependency>
</dependencies>

3. Module Configuration

Multi‑module projects use the modules tag in the parent POM.

<modules>
    <module>module‑1</module>
    <module>module‑2</module>
</modules>

Child modules inherit groupId , artifactId , and version from the parent via the parent element.

4. Unified Dependency Management

Common dependencies are declared once in the parent’s dependencyManagement section and inherited by child modules.

<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql‑connector‑java</artifactId>
            <version>8.0.30</version>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.13.2</version>
        </dependency>
    </dependencies>
</dependencyManagement>

5. Plugin Management

5.1 Maven‑Jar‑Plugin

Customizes the JAR manifest.

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven‑jar‑plugin</artifactId>
    <version>2.3.1</version>
    <configuration>
        <archive>
            <manifest>
                <mainClass>org.example.MyTest</mainClass>
                <addDefaultSpecificationEntries>true</addDefaultSpecificationEntries>
                <addDefaultImplementationEntries>true</addDefaultImplementationEntries>
                <manifestEntries>
                    <Plugin‑Id>demo‑plugin</Plugin‑Id>
                    <Plugin‑Version>1.0.0</Plugin‑Version>
                </manifestEntries>
            </manifest>
        </archive>
    </configuration>
</plugin>

5.2 Maven‑Assembly‑Plugin

Packages all project classes together with their dependencies.

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven‑assembly‑plugin</artifactId>
    <version>3.1.0</version>
    <configuration>
        <descriptorRefs>
            <descriptorRef>jar‑with‑dependencies</descriptorRef>
        </descriptorRefs>
        <finalName>${project.artifactId}-${project.version}-all</finalName>
        <appendAssemblyId>false</appendAssemblyId>
        <attach>false</attach>
    </configuration>
    <executions>
        <execution>
            <id>make‑assembly</id>
            <phase>package</phase>
            <goals>
                <goal>single</goal>
            </goals>
        </execution>
    </executions>
</plugin>

5.3 Maven‑Shade‑Plugin

Creates an uber‑JAR with optional class relocation and selective inclusion.

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven‑shade‑plugin</artifactId>
    <version>3.2.0</version>
    <executions>
        <execution>
            <phase>package</phase>
            <goals>
                <goal>shade</goal>
            </goals>
        </execution>
    </executions>
    <configuration>
        <minimizeJar>true</minimizeJar>
        <artifactSet>
            <includes>
                <include>com.fasterxml.jackson.core:jackson‑core</include>
            </includes>
        </artifactSet>
        <relocations>
            <relocation>
                <pattern>com.fasterxml.jackson.core</pattern>
                <shadedPattern>com.ibudai.fasterxml.jackson.core</shadedPattern>
            </relocation>
        </relocations>
        <filters>
            <filter>
                <artifact>*:*</artifact>
                <excludes>
                    <exclude>META‑INF/license/**</exclude>
                    <exclude>META‑INF/*</exclude>
                    <exclude>LICENSE</exclude>
                    <exclude>NOTICE</exclude>
                </excludes>
            </filter>
        </filters>
    </configuration>
</plugin>

6. Build Configuration

6.1 JDK Version

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven‑compiler‑plugin</artifactId>
    <version>3.1</version>
    <configuration>
        <source>8</source>
        <target>8</target>
    </configuration>
</plugin>

6.2 Resource Exclusion

<resources>
    <resource>
        <directory>src/main/resources</directory>
        <excludes>
            <exclude>application.yml</exclude>
        </excludes>
    </resource>
</resources>

6.3 Main Class Specification

<plugin>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring‑boot‑maven‑plugin</artifactId>
    <configuration>
        <mainClass>xyz.ibudai.TestWebApplication</mainClass>
        <layout>JAR</layout>
    </configuration>
</plugin>

By following these configurations, developers can efficiently manage dependencies, avoid version conflicts, build modular Maven projects, and produce executable JARs with the desired metadata and bundled libraries.