The following examples describe the basic usage of the Checkstyle Plugin.
To generate the Checkstyle report as part of the Project Reports, add the Checkstyle Plugin in the <reporting> section of your pom.xml.
<project>
  ...
  <reporting>
    <plugins>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-checkstyle-plugin</artifactId>
        <version>2.4</version>
      </plugin>
    </plugins>
  </reporting>
  ...
</project>
Then, execute the site phase to generate the report.
mvn site
You can also generate the Checkstyle report by explicitly executing the checkstyle:checkstyle goal from the command line. It is not required to specify the Checkstyle Plugin in your pom.xml unless you want to use a specific configuration.
mvn checkstyle:checkstyle
To specifically configure the Checkstyle Plugin, you need to the add it in the <build> section of your pom.xml as shown in the sample below.
<project>
  ...
  <build>
    <plugins>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-checkstyle-plugin</artifactId>
        <version>2.4</version>
        <configuration>
          <enableRulesSummary>false</enableRulesSummary>
           ...
        </configuration>
      </plugin>
    </plugins>
  </build>
  ...
</project>