The Simian plugin listed in the center is actually for Maven 1 (if you check the contents, you will see the project.xml file and plugin.jelly). Therefore, this explains why this does not work. This is trash and should be removed in my opinion.
As far as I can tell, there is no public Maven 2 plugin, this may have something to do with the license (Simian isn't open source ).
Alternatively, take a look at the PMD CPD plugin , it may not be as full-featured as simian, but I know that it works in Maven 2 it creates and detects copypasta pretty well.
PMD, POM - :
<reporting>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-pmd-plugin</artifactId>
<version>2.4</version>
</plugin>
</plugins>
</reporting>