This page contains information about how to upgrade plugins to newer Maven versions, parent version or Java versions.

TODO ideas:

• create OpenRewrite recipe to automate changes like https://github.com/openrewrite/rewrite-apache/blob/main/src/main/java/org/openrewrite/codehaus/plexus/AbstractLogEnabledToSlf4j.java 
  Can help other plugin developers to migrate easly

Java updates

Java 25

• Update Invoker plugin to 3.9.1
• Upgrade spotless palantir format 

<version.palantirJavaFormat>2.82.0</version.palantirJavaFormat>

Update site descriptor (site.xml)

To 2.0.0

<!-- from -->
<project xmlns="http://maven.apache.org/DECORATION/1.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/DECORATION/1.0.0 http://maven.apache.org/xsd/decoration-1.0.0.xsd"
         name="JXR">

</project>

<!-- to -->

<site xmlns="http://maven.apache.org/SITE/2.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
      xsi:schemaLocation="http://maven.apache.org/SITE/2.0.0 https://maven.apache.org/xsd/site-2.0.0.xsd" name="JXR">

</site

There might be other changes required, depending of the elements used by the site, example banners

<!-- from -->
  <bannerRight>
    <name>Doxia</name>
    <src>https://maven.apache.org/doxia/images/doxia-logo.png</src>
    <href>https://maven.apache.org/doxia/</href>
  </bannerRight>

<!-- to -->
  <bannerRight name="Doxia" href="https://maven.apache.org/doxia/">
    <image src="https://maven.apache.org/doxia/images/doxia-logo.png" />
  </bannerRight>

Doxia 1 to 2

https://github.com/apache/maven-changelog-plugin/pull/208/changes

Update JUnit / Plugin harness

• Junit 4
  • Add <version>4.13.2</version> dependency and  <artifactId>maven-plugin-testing-harness</artifactId> 3.4.0 (Example: DOAP-Plguin Update to 3.9.11 and JUnit 4)
    • Maybe with vintage engine for JUnt Jupiter Inject Deploy-Plugin to JUnit Jupiter
• Junit 5 https://github.com/apache/maven-resources-plugin/pull/447

Maven upgrades 

General

• Make sure Maven version is available on CI (must be done by INFRA, so request for install is needed)
• Do not update Maven version in ".github/workflows/maven-verify.yml" and "pom.xml". Instead update per project as those must match.

to 3.9.11 (e.g. from 3.6.3) (Example: DOAP-Plguin Update to 3.9.11)

• Update  mavenVersion property to 3.9.11 (<mavenVersion>3.9.11</mavenVersion>)
• Replace org.apache.maven.plugins.annotations.Component; with import javax.inject.Inject;

to 4.0.0-rc3

to 4.0.0-rc4

to 4.0.0-rc5

Parent upgrades

To 45

• Update parent version
• Fix checkstyle violations (also in tests classes)
• Update site descriptor (if not done yet) (see above)
• Set version of  maven-plugin-annotations
• Maybe fix IT by adding languages to expected directories https://github.com/apache/maven-archetypes/pull/126

<dependency>
      <groupId>org.apache.maven.plugin-tools</groupId>
      <artifactId>maven-plugin-annotations</artifactId>
      <version>${version.maven-plugin-tools}</version>
      <scope>provided</scope>
    </dependency>
    <dependency>

To 46

• Check explicit set version 3.9.1 of maven-invoker-plugin and remove it, as it is set in parent 46
• Replace fixed verisons of plugins in ITs to placeholders of parent (https://github.com/apache/maven-apache-parent/blob/master/pom.xml) 

Example parent-placeholder of deploy-plugin (of antrun-plugin https://github.com/apache/maven-antrun-plugin/pull/353)

          
<artifactId>maven-deploy-plugin</artifactId>
<version>@version.maven-deploy-plugin@</version>

JUnit / Test cases update

• Migrate AbstractMojoTestCase to TestMojo (Example https://github.com/apache/maven-war-plugin/pull/579#pullrequestreview-3505113259 )
• Use Maven Plugin Testing Harness:
  •  https://maven.apache.org/plugin-testing/maven-plugin-testing-harness/getting-started/index.html
  • https://github.com/apache/maven-jxr/pull/346