gistfile1.java

import org.apache.maven.plugin.AbstractMojo;
import org.apache.maven.plugin.MojoExecutionException;
import org.apache.maven.plugin.MojoFailureException;

/**
 * @goal art
 * @phase package
 */
public class App extends AbstractMojo
{
    public void execute() throws MojoExecutionException, MojoFailureException {
        String s = ".\n" +
                   " XX      XX  NN      NN                         _ _\n" +
                   "  XX    XX   NNN     NN              |\\__/|  .~    ~.\n" +
                   "   XX  XX    NNNN    NN              /  o `./      .'\n" +
                   "    XXXX     NN NN   NN             {o__,   \\    {\n" +
                   "    XXXX     NN  NN  NN               / .  . )    \\\n" +
                   "   XX  XX    NN   NN NN               `-` '-' \\    }  \n" +
                   "  XX    XX   NN    NNNN              .(   _(   )_.'\n" +
                   " XX      XX  NN     NNN             '---.~_ _ _|\n" +
                   ".\n" +
                   "\n";

        String[] lines = s.split("\\n");
        for (int i = 0; i < lines.length; i++){
            this.getLog().info(lines[i]);
        }
    }
}

plugin.xml

<plugin>
  <description></description>
  <groupId>ning.maven</groupId>
  <artifactId>xn</artifactId>
  <version>1.0-SNAPSHOT</version>
  <goalPrefix>xn</goalPrefix>
  <isolatedRealm>false</isolatedRealm>
  <inheritedByDefault>true</inheritedByDefault>
  <mojos>
    <mojo>
      <goal>art</goal>
      <description></description>
      <requiresDirectInvocation>false</requiresDirectInvocation>
      <requiresProject>true</requiresProject>
      <requiresReports>false</requiresReports>
      <aggregator>false</aggregator>
      <requiresOnline>false</requiresOnline>
      <inheritedByDefault>true</inheritedByDefault>
      <phase>package</phase>
      <implementation>ning.maven.App</implementation>
      <language>java</language>
      <instantiationStrategy>per-lookup</instantiationStrategy>
      <executionStrategy>once-per-session</executionStrategy>
      <parameters/>
    </mojo>
  </mojos>
  <dependencies>
    <dependency>
      <groupId>org.apache.maven</groupId>
      <artifactId>maven-plugin-api</artifactId>
      <type>jar</type>
      <version>2.0</version>
    </dependency>
  </dependencies>
</plugin>

pom.xml

<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/maven-v4_0_0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>ning.maven</groupId>
    <artifactId>xn</artifactId>

    <packaging>maven-plugin</packaging>
    <version>1.0-SNAPSHOT</version>
    <name>xn</name>
    <url>http://maven.apache.org</url>
    <dependencies>
        <dependency>
            <groupId>org.apache.maven</groupId>
            <artifactId>maven-plugin-api</artifactId>
            <version>2.0</version>
        </dependency>
    </dependencies>


    <build>
        <plugins>
            <plugin>
                <groupId>ning.maven</groupId>
                <artifactId>xn</artifactId>
                <version>1.0-SNAPSHOT</version>
                <!--<executions>-->
                    <!--<execution>-->
                        <!--<phase>compile</phase>-->
                        <!--<goals>-->
                            <!--<goal>art</goal>-->
                        <!--</goals>-->
                    <!--</execution>-->
                <!--</executions>-->
            </plugin>
        </plugins>
    </build>
</project>