Maven Plugin Configuration

Master Maven plugin configuration including core plugins, build plugins, reporting plugins, and custom plugin development.

Overview

Maven plugins provide the actual functionality for building projects. Understanding how to configure plugins effectively is essential for customizing builds, optimizing performance, and ensuring code quality.

Plugin Basics

Plugin Structure

<build>
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>3.12.1</version>
            <configuration>
                <!-- Plugin-specific configuration -->
            </configuration>
            <executions>
                <execution>
                    <id>compile-java</id>
                    <phase>compile</phase>
                    <goals>
                        <goal>compile</goal>
                    </goals>
                </execution>
            </executions>
        </plugin>
    </plugins>
</build>

Plugin Management

<build>
    <pluginManagement>
        <plugins>
            <!-- Define versions and shared config -->
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.12.1</version>
                <configuration>
                    <release>17</release>
                </configuration>
            </plugin>
        </plugins>
    </pluginManagement>
    <plugins>
        <!-- Actually use plugin (inherits config) -->
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
        </plugin>
    </plugins>
</build>

Core Build Plugins

Compiler Plugin

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-compiler-plugin</artifactId>
    <version>3.12.1</version>
    <configuration>
        <release>17</release>
        <encoding>UTF-8</encoding>
        <showWarnings>true</showWarnings>
        <showDeprecation>true</showDeprecation>
        <compilerArgs>
            <arg>-Xlint:all</arg>
            <arg>-parameters</arg>
        </compilerArgs>
        <annotationProcessorPaths>
            <path>
                <groupId>org.projectlombok</groupId>
                <artifactId>lombok</artifactId>
                <version>1.18.30</version>
            </path>
        </annotationProcessorPaths>
    </configuration>
</plugin>

Resources Plugin

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-resources-plugin</artifactId>
    <version>3.3.1</version>
    <configuration>
        <encoding>UTF-8</encoding>
        <propertiesEncoding>UTF-8</propertiesEncoding>
        <nonFilteredFileExtensions>
            <nonFilteredFileExtension>pdf</nonFilteredFileExtension>
            <nonFilteredFileExtension>ico</nonFilteredFileExtension>
            <nonFilteredFileExtension>png</nonFilteredFileExtension>
            <nonFilteredFileExtension>jpg</nonFilteredFileExtension>
        </nonFilteredFileExtensions>
    </configuration>
</plugin>

JAR Plugin

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-jar-plugin</artifactId>
    <version>3.3.0</version>
    <configuration>
        <archive>
            <manifest>
                <addClasspath>true</addClasspath>
                <mainClass>com.example.Main</mainClass>
                <addDefaultImplementationEntries>true</addDefaultImplementationEntries>
                <addDefaultSpecificationEntries>true</addDefaultSpecificationEntries>
            </manifest>
            <manifestEntries>
                <Build-Time>${maven.build.timestamp}</Build-Time>
                <Built-By>${user.name}</Built-By>
            </manifestEntries>
        </archive>
        <excludes>
            <exclude>**/logback-test.xml</exclude>
        </excludes>
    </configuration>
    <executions>
        <execution>
            <id>test-jar</id>
            <goals>
                <goal>test-jar</goal>
            </goals>
        </execution>
    </executions>
</plugin>

Source Plugin

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-source-plugin</artifactId>
    <version>3.3.0</version>
    <executions>
        <execution>
            <id>attach-sources</id>
            <goals>
                <goal>jar-no-fork</goal>
            </goals>
        </execution>
    </executions>
</plugin>

Javadoc Plugin

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-javadoc-plugin</artifactId>
    <version>3.6.3</version>
    <configuration>
        <doclint>none</doclint>
        <source>17</source>
        <quiet>true</quiet>
        <links>
            <link>https://docs.oracle.com/en/java/javase/17/docs/api/</link>
        </links>
    </configuration>
    <executions>
        <execution>
            <id>attach-javadocs</id>
            <goals>
                <goal>jar</goal>
            </goals>
        </execution>
    </executions>
</plugin>

Testing Plugins

Surefire Plugin (Unit Tests)

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-surefire-plugin</artifactId>
    <version>3.2.3</version>
    <configuration>
        <includes>
            <include>**/*Test.java</include>
            <include>**/*Tests.java</include>
            <include>**/Test*.java</include>
        </includes>
        <excludes>
            <exclude>**/*IT.java</exclude>
            <exclude>**/*IntegrationTest.java</exclude>
        </excludes>
        <argLine>-Xmx1024m -XX:+UseG1GC</argLine>
        <parallel>methods</parallel>
        <threadCount>4</threadCount>
        <forkCount>1C</forkCount>
        <reuseForks>true</reuseForks>
        <systemPropertyVariables>
            <spring.profiles.active>test</spring.profiles.active>
        </systemPropertyVariables>
        <environmentVariables>
            <TEST_ENV>true</TEST_ENV>
        </environmentVariables>
    </configuration>
</plugin>

Failsafe Plugin (Integration Tests)

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-failsafe-plugin</artifactId>
    <version>3.2.3</version>
    <configuration>
        <includes>
            <include>**/*IT.java</include>
            <include>**/*IntegrationTest.java</include>
        </includes>
        <skipAfterFailureCount>3</skipAfterFailureCount>
    </configuration>
    <executions>
        <execution>
            <goals>
                <goal>integration-test</goal>
                <goal>verify</goal>
            </goals>
        </execution>
    </executions>
</plugin>

JaCoCo Plugin (Code Coverage)

<plugin>
    <groupId>org.jacoco</groupId>
    <artifactId>jacoco-maven-plugin</artifactId>
    <version>0.8.11</version>
    <executions>
        <execution>
            <id>prepare-agent</id>
            <goals>
                <goal>prepare-agent</goal>
            </goals>
        </execution>
        <execution>
            <id>report</id>
            <phase>test</phase>
            <goals>
                <goal>report</goal>
            </goals>
        </execution>
        <execution>
            <id>check</id>
            <goals>
                <goal>check</goal>
            </goals>
            <configuration>
                <rules>
                    <rule>
                        <element>BUNDLE</element>
                        <limits>
                            <limit>
                                <counter>LINE</counter>
                                <value>COVEREDRATIO</value>
                                <minimum>0.80</minimum>
                            </limit>
                            <limit>
                                <counter>BRANCH</counter>
                                <value>COVEREDRATIO</value>
                                <minimum>0.70</minimum>
                            </limit>
                        </limits>
                    </rule>
                </rules>
            </configuration>
        </execution>
    </executions>
</plugin>

Quality Plugins

Enforcer Plugin

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-enforcer-plugin</artifactId>
    <version>3.4.1</version>
    <executions>
        <execution>
            <id>enforce</id>
            <goals>
                <goal>enforce</goal>
            </goals>
            <configuration>
                <rules>
                    <requireMavenVersion>
                        <version>[3.8.0,)</version>
                    </requireMavenVersion>
                    <requireJavaVersion>
                        <version>[17,)</version>
                    </requireJavaVersion>
                    <dependencyConvergence/>
                    <requireUpperBoundDeps/>
                    <banDuplicatePomDependencyVersions/>
                    <bannedDependencies>
                        <excludes>
                            <exclude>commons-logging:commons-logging</exclude>
                            <exclude>log4j:log4j</exclude>
                        </excludes>
                    </bannedDependencies>
                </rules>
            </configuration>
        </execution>
    </executions>
</plugin>

Checkstyle Plugin

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-checkstyle-plugin</artifactId>
    <version>3.3.1</version>
    <configuration>
        <configLocation>checkstyle.xml</configLocation>
        <consoleOutput>true</consoleOutput>
        <failsOnError>true</failsOnError>
        <violationSeverity>warning</violationSeverity>
        <includeTestSourceDirectory>true</includeTestSourceDirectory>
    </configuration>
    <executions>
        <execution>
            <id>checkstyle</id>
            <phase>validate</phase>
            <goals>
                <goal>check</goal>
            </goals>
        </execution>
    </executions>
    <dependencies>
        <dependency>
            <groupId>com.puppycrawl.tools</groupId>
            <artifactId>checkstyle</artifactId>
            <version>10.12.6</version>
        </dependency>
    </dependencies>
</plugin>

SpotBugs Plugin

<plugin>
    <groupId>com.github.spotbugs</groupId>
    <artifactId>spotbugs-maven-plugin</artifactId>
    <version>4.8.3.0</version>
    <configuration>
        <effort>Max</effort>
        <threshold>Low</threshold>
        <xmlOutput>true</xmlOutput>
        <excludeFilterFile>spotbugs-exclude.xml</excludeFilterFile>
    </configuration>
    <executions>
        <execution>
            <goals>
                <goal>check</goal>
            </goals>
        </execution>
    </executions>
</plugin>

PMD Plugin

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-pmd-plugin</artifactId>
    <version>3.21.2</version>
    <configuration>
        <rulesets>
            <ruleset>/category/java/bestpractices.xml</ruleset>
            <ruleset>/category/java/errorprone.xml</ruleset>
        </rulesets>
        <failOnViolation>true</failOnViolation>
        <printFailingErrors>true</printFailingErrors>
        <includeTests>true</includeTests>
        <targetJdk>17</targetJdk>
    </configuration>
    <executions>
        <execution>
            <goals>
                <goal>check</goal>
                <goal>cpd-check</goal>
            </goals>
        </execution>
    </executions>
</plugin>

Packaging Plugins

Assembly Plugin

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-assembly-plugin</artifactId>
    <version>3.6.0</version>
    <configuration>
        <descriptorRefs>
            <descriptorRef>jar-with-dependencies</descriptorRef>
        </descriptorRefs>
        <archive>
            <manifest>
                <mainClass>com.example.Main</mainClass>
            </manifest>
        </archive>
    </configuration>
    <executions>
        <execution>
            <id>make-assembly</id>
            <phase>package</phase>
            <goals>
                <goal>single</goal>
            </goals>
        </execution>
    </executions>
</plugin>

Shade Plugin

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-shade-plugin</artifactId>
    <version>3.5.1</version>
    <executions>
        <execution>
            <phase>package</phase>
            <goals>
                <goal>shade</goal>
            </goals>
            <configuration>
                <transformers>
                    <transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
                        <mainClass>com.example.Main</mainClass>
                    </transformer>
                    <transformer implementation="org.apache.maven.plugins.shade.resource.ServicesResourceTransformer"/>
                </transformers>
                <filters>
                    <filter>
                        <artifact>*:*</artifact>
                        <excludes>
                            <exclude>META-INF/*.SF</exclude>
                            <exclude>META-INF/*.DSA</exclude>
                            <exclude>META-INF/*.RSA</exclude>
                        </excludes>
                    </filter>
                </filters>
                <relocations>
                    <relocation>
                        <pattern>com.google</pattern>
                        <shadedPattern>shaded.com.google</shadedPattern>
                    </relocation>
                </relocations>
            </configuration>
        </execution>
    </executions>
</plugin>

WAR Plugin

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-war-plugin</artifactId>
    <version>3.4.0</version>
    <configuration>
        <failOnMissingWebXml>false</failOnMissingWebXml>
        <packagingExcludes>WEB-INF/classes/logback-test.xml</packagingExcludes>
        <webResources>
            <resource>
                <directory>src/main/webapp</directory>
                <filtering>true</filtering>
                <includes>
                    <include>**/*.html</include>
                </includes>
            </resource>
        </webResources>
    </configuration>
</plugin>

Spring Boot Plugin

<plugin>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-maven-plugin</artifactId>
    <version>3.2.0</version>
    <configuration>
        <mainClass>com.example.Application</mainClass>
        <excludes>
            <exclude>
                <groupId>org.projectlombok</groupId>
                <artifactId>lombok</artifactId>
            </exclude>
        </excludes>
        <layers>
            <enabled>true</enabled>
        </layers>
        <image>
            <name>${project.artifactId}:${project.version}</name>
            <builder>paketobuildpacks/builder:base</builder>
        </image>
    </configuration>
    <executions>
        <execution>
            <goals>
                <goal>repackage</goal>
            </goals>
        </execution>
    </executions>
</plugin>

Version Management Plugins

Versions Plugin

<plugin>
    <groupId>org.codehaus.mojo</groupId>
    <artifactId>versions-maven-plugin</artifactId>
    <version>2.16.2</version>
    <configuration>
        <rulesUri>file:///${project.basedir}/version-rules.xml</rulesUri>
    </configuration>
</plugin>

# Check for updates
mvn versions:display-dependency-updates
mvn versions:display-plugin-updates
mvn versions:display-property-updates

# Update versions
mvn versions:update-properties
mvn versions:use-latest-releases
mvn versions:update-parent

Release Plugin

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-release-plugin</artifactId>
    <version>3.0.1</version>
    <configuration>
        <tagNameFormat>v@{project.version}</tagNameFormat>
        <autoVersionSubmodules>true</autoVersionSubmodules>
        <releaseProfiles>release</releaseProfiles>
    </configuration>
</plugin>

Code Generation Plugins

Build Helper Plugin

<plugin>
    <groupId>org.codehaus.mojo</groupId>
    <artifactId>build-helper-maven-plugin</artifactId>
    <version>3.5.0</version>
    <executions>
        <execution>
            <id>add-source</id>
            <phase>generate-sources</phase>
            <goals>
                <goal>add-source</goal>
            </goals>
            <configuration>
                <sources>
                    <source>${project.build.directory}/generated-sources</source>
                </sources>
            </configuration>
        </execution>
    </executions>
</plugin>

Exec Plugin

<plugin>
    <groupId>org.codehaus.mojo</groupId>
    <artifactId>exec-maven-plugin</artifactId>
    <version>3.1.1</version>
    <executions>
        <execution>
            <id>run-script</id>
            <phase>generate-sources</phase>
            <goals>
                <goal>exec</goal>
            </goals>
            <configuration>
                <executable>bash</executable>
                <arguments>
                    <argument>${project.basedir}/scripts/generate.sh</argument>
                </arguments>
            </configuration>
        </execution>
    </executions>
</plugin>

Best Practices

1. Version Pinning - Always specify plugin versions
2. Plugin Management - Centralize in parent POM
3. Minimal Configuration - Use defaults where possible
4. Execution IDs - Use meaningful execution IDs
5. Phase Binding - Bind to appropriate phases
6. Skip Properties - Provide skip properties for flexibility
7. Documentation - Comment complex configurations
8. Inheritance - Use pluginManagement for multi-module
9. Updates - Keep plugins current
10. Profile Separation - Separate CI/release plugins into profiles

Common Pitfalls

1. Missing Versions - Relying on default versions
2. Wrong Phase - Plugin bound to wrong lifecycle phase
3. Duplicate Executions - Same goal running multiple times
4. Memory Issues - Insufficient heap for plugins
5. Ordering - Plugin execution order conflicts
6. Inheritance - Unintended plugin inheritance
7. Fork Confusion - Misunderstanding fork behavior
8. Skip Flags - Tests accidentally skipped in CI

When to Use This Skill

• Configuring build compilation settings
• Setting up test frameworks
• Configuring code quality checks
• Creating executable JARs
• Setting up CI/CD builds
• Optimizing build performance
• Generating source code
• Managing releases and versions