Plugins in Maven and POM.xml
JavaMavenMaven 3pom.xmlMaven PluginJava Problem Overview
I just started using Maven and I read that plugins are additional components that can be used.
A typical structure of pom.xml file is
<project>
<groupId>org.koshik.javabrains</groupId>
<artifactId>JarName</artifactId> (A fldernamed JarName was created)
<version>1.0-SNAPSHOT</version>
<packaging>jar</packaging>
<name>JarName</name>
<url>http://maven.apache.org</url>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>3.8.1</version>
<scope>test</scope>
</dependency>
</dependencies>
</project>
Question: Where should I insert a plugin tag? such as the following:
<plugin>
<groupId>org.jibx</groupId>
<artifactId>jibx-maven-plugin</artifactId>
<version>1.2.4</version>
<executions>
<execution>
<goals>
<goal>bind</goal>
</goals>
</execution>
</executions>
</plugin>
Before the dependency or after the dependency tag? Does it matter?
Java Solutions
Solution 1 - Java
<project>
<groupId>org.koshik.javabrains</groupId>
<artifactId>JarName</artifactId> (A fldernamed JarName was created)
<version>1.0-SNAPSHOT</version>
<packaging>jar</packaging>
<name>JarName</name>
<url>http://maven.apache.org</url>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>
<build>
<plugins>
<plugin>
<groupId>org.jibx</groupId>
<artifactId>jibx-maven-plugin</artifactId>
<version>1.2.4</version>
<executions>
<execution>
<goals>
<goal>bind</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>3.8.1</version>
<scope>test</scope>
</dependency>
</dependencies>
</project>
You can also place plugins in the <build> section of <profile> if you use maven profiles. The order doesn't matter.
Solution 2 - Java
A late clarification on two important points
Where to place plugin
A plugin should indeed be added in most of the cases within the build/plugins section, however there is an important difference between placing it within plugins against placing it within pluginManagement/plugins.
This misunderstanding is often the cause of a non invoked plugin in Maven or an harder troubleshooting:
-
Plugins under
build/pluginsare directly part of the default Maven build, if they specify anexecutionor if they configure something for the default build (see below) -
Plugins under
build/pluginManagement/pluginsare not necessarely part of the default Maven build, that is, is a management, it's an hint to maven: it you happen to use this plugin, then please use the version, the configuration, the executions I specify here, in this management.But what happen to use means? Means: if the same plugin is also present in the
build/pluginssection, then apply this management (and only then it will be effective); or if the plugin is invoked by default by Maven, then also apply it.
But how is a plugin invoked by default? That's part of the main philosophy behind maven: convention over configuration. By convention, when you specify a certain packaging (default jar, but it can be war for example), you want certain plugins to be invoked. To build a jar, by default invoke the maven-jar-plugin; to build a war, by default invoke the maven-war-plugin and so on. So, if you specify a plugin configuration in the build/pluginManagement/plugin for a plugin which has a default binding to the Maven build, then it will be also be used.
Ordering
Concerning the ordering of sections within the pom.xml file, a further clarification is required: it's indeed irrelevant in most of the cases, however the order of plugin element wihtin the build/plugins section may be important. Since Maven 3.0.3 (MNG-2258), different plugin executions attached to the same Maven phase will be invoked in their order of declaration in the pom.xml file. That is, ordering is important in this case, since it may affect the behavior of the build.
Additionally, also order of dependency declarations may affect your build towards Dependency Mediation, that is, the first declared dependency wins in case of conflict against a transitive dependency. So, once again, ordering is important in certain cases.
Last but not least, although ordering is not important for other sections of the pom.xml file, good habit is to follow official Maven recommendations and, as a simplified version, follow this order of declaration:
<project>
<modelVersion/>
<parent/>
<groupId/>
<artifactId/>
<version/>
<packaging/>
<properties/>
<dependencyManagement/>
<dependencies/>
<build/>
<reporting/>
<profiles/>
</project>
The sortpom-maven-plugin can also be used to automatically apply this standard ordering, simply invoking the following on the concerned pom.xml file:
mvn com.github.ekryd.sortpom:sortpom-maven-plugin:2.5.0:sort \
-Dsort.keepBlankLines -Dsort.predefinedSortOrder=recommended_2008_06
For further reading:
Solution 3 - Java
<plugin>should be placed into <plugins> section which should be placed into <build> or <pluginManagement> section.
The order of <dependency> or <build> section doesn't matter.
The full reference about pom.xml is here: http://maven.apache.org/pom.html
Solution 4 - Java
If you want to use the plugin for build you can use the below structure.
<project>
<build>
<plugins>
</plugins>
</build>
</project>
Solution 5 - Java
You can insert your second snippet anywhere in the pom.xml file between two <plugins> </plugins> tags.
Solution 6 - Java
Sections order in POM doesn't matter. In general, there are build plugins and reporting plugins in Maven. Your case is to use build plugin so you have to put this <plugin> block into <project><build><plugins>... section.
Look at this for some basics about plugins.
Solution 7 - Java
As additional answer for Reporting Plugins (e.g. maven-checkstyle-plugin) there are 2 tags under which plugins can go in pom.xml, under build and reporting.
>Using the reporting Tag VS build Tag
>
> Configuring a reporting plugin in the