Maven - Plugins

What are Maven Plugins?

Maven is actually a plugin execution framework where every task is actually done by plugins. Maven Plugins are generally used to −

create jar file

create war file

compile code files

unit testing of code

create project documentation

create project reports

A plugin generally provides a set of goals, which can be executed using the following syntax −

mvn [plugin-name]:[goal-name]

For example, a Java project can be compiled with the maven-compiler-plugin s compile-goal by running the following command.

mvn compiler:compile

Plugin Types

Maven provided the following two types of Plugins −

Following is the pst of few common plugins −

Example

We ve used maven-antrun-plugin extensively in our examples to print data on console. Refer Build Profiles chapter. Let us understand it in a better way and create a pom.xml in C:MVNproject folder.

<project xmlns = "http://maven.apache.org/POM/4.0.0"
   xmlns:xsi = "http://www.w3.org/2001/XMLSchema-instance"
   xsi:schemaLocation = "http://maven.apache.org/POM/4.0.0
   http://maven.apache.org/xsd/maven-4.0.0.xsd">
   <modelVersion>4.0.0</modelVersion>
   <groupId>com.companyname.projectgroup</groupId>
   <artifactId>project</artifactId>
   <version>1.0</version>
   <build>
      <plugins>
         <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-antrun-plugin</artifactId>
            <version>1.1</version>
            <executions>
               <execution>
                  <id>id.clean</id>
                  <phase>clean</phase>
                  <goals>
                     <goal>run</goal>
                  </goals>
                  <configuration>
                     <tasks>
                        <echo>clean phase</echo>
                     </tasks>
                  </configuration>
               </execution>     
            </executions>
         </plugin>
      </plugins>
   </build>
</project>

Next, open the command console and go to the folder containing pom.xml and execute the following mvn command.

C:MVNproject>mvn clean

Maven will start processing and displaying the clean phase of clean pfe cycle.

C:MVN>mvn clean
[INFO] Scanning for projects...
[INFO]
[INFO] ----------------< com.companyname.projectgroup:project >----------------
[INFO] Building project 1.0
[INFO] --------------------------------[ jar ]---------------------------------
[INFO]
[INFO] --- maven-clean-plugin:2.5:clean (default-clean) @ project ---
[INFO] Deleting C:MVN	arget
[INFO]
[INFO] --- maven-antrun-plugin:1.1:run (id.clean) @ project ---
[INFO] Executing tasks
     [echo] clean phase
[INFO] Executed tasks
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  1.266 s
[INFO] Finished at: 2021-12-13T13:58:10+05:30
[INFO] ------------------------------------------------------------------------

C:MVN>

The above example illustrates the following key concepts −

Plugins are specified in pom.xml using plugins element.

Each plugin can have multiple goals.

You can define phase from where plugin should starts its processing using its phase element. We ve used clean phase.

You can configure tasks to be executed by binding them to goals of plugin. We ve bound echo task with run goal of maven-antrun-plugin.

Maven will then download the plugin if not available in local repository and start its processing.