Simplistic using Groovy in Maven - maven

Question

In some maven project I'll try to figure out how can be used Groovy language. For instance, I try to create a directory in validation phase, by using something like that
<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">
...
<dependencies>
...
<dependency>
<groupId>org.codehaus.groovy</groupId>
<artifactId>groovy-all</artifactId>
<version>2.5.5</version>
<type>pom</type>
<scope>runtime</scope>
</dependency>
...
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.codehaus.gmaven</groupId>
<artifactId>groovy-maven-plugin</artifactId>
<version>2.0</version>
<executions>
<execution>
<id>Project</id>
<phase>validate</phase>
<goals>
<goal>execute</goal>
</goals>
</execution>
</executions>
<configuration>
<source>
final FileTreeBuilder treeBuilder = new FileTreeBuilder(new File('tree'))
def folder = new File( 'sample_dir' )
if(!folder.exists()){
treeBuilder.dir('sample_dir')
}
</source>
</configuration>
</plugin>
...
</plugins>
</build>
But if it using the command mvn compile will be present error
[ERROR] script1.groovy: 3: unable to resolve class FileTreeBuilder
What have I missed and what should be added to make this plugin functional?

Answer 1

https://groovy.github.io/gmaven/groovy-maven-plugin/
Customizing Groovy Version
To customize the version of Groovy the plugin will use, override the org.codehaus.groovy:groovy-all dependency on the plugin definition in the project.
For example to use Groovy 2.0.6 instead of the default:
<plugin>
<groupId>org.codehaus.gmaven</groupId>
<artifactId>groovy-maven-plugin</artifactId>
<dependencies>
<dependency>
<groupId>org.codehaus.groovy</groupId>
<artifactId>groovy-all</artifactId>
<version>2.0.6</version>
</dependency>
</dependencies>
</plugin>