Excluding classes in Maven Checkstyle plugin reports

Additionally, if you want to exclude multiple independent folders, you can add multiple independent paths comma separated like this

<excludes>org/log4j/*,com/acme/**/*,com/companyb/*</excludes>

If, like me, you arrived here searching for a way to exclude generated sources from checkstyle, do this:

<plugin>
  <groupId>org.apache.maven.plugins</groupId>
  <artifactId>maven-checkstyle-plugin</artifactId>
  <version>2.15</version>
  <configuration>
    <sourceDirectory>${project.build.sourceDirectory}</sourceDirectory>
  </configuration>
</plugin>

By default, the checkstyle:checkstyle goal of the checkstyle plugin uses ${project.compileSourceRoots}, which apparently includes generated source directories.

If you change it to ${project.build.sourceDirectory}, it will use only the source directory, not any generated source directories.

Note that while <sourceDirectory> is deprecated, the alternative, <sourceDirectories>, does not appear to work.

Edit: In comments, @Cyrusmith, @Ben, and @Olivier Callioux report that as of 2017, <sourceDirectories> works; I cannot confirm.

If this question is about Maven 2, then the property is excludes and takes a comma-separated list of Ant patterns. So either pass this on the command line:

-Dexcludes=**/generated/**/*

Or set it up in the plugin configuration:

<plugin>
   <groupId>org.apache.maven.plugins</groupId>
   <artifactId>maven-checkstyle-plugin</artifactId>
   <configuration>
       <excludes>**/generated/**/*</excludes>
   </configuration>
</plugin>

Another option would be to use a suppression filter.

For example you could use the SuppressionCommentFilter to suppress audit events between a comment containing CHECKSTYLE:OFF and a comment containing CHECKSTYLE:ON (then just add these comments to the classes or parts of the code you don't want to check).