Obfuscate with yGuard in Maven

pom-snippet.xml

<plugin>
    <artifactId>maven-antrun-plugin</artifactId>
    <version>1.8</version>
    <executions>
        <execution>
            <phase>package</phase>
            <goals>
                <goal>run</goal>
            </goals>
            <configuration>
                <tasks>
                    <property refid="maven.compile.classpath" name="mvn.classpath"></property>
                    <taskdef name="yguard" classname="com.yworks.yguard.YGuardTask"
                             classpath="lib/yguard.jar"/>
                    <yguard>
                        <inoutpair in="${project.build.directory}/${project.build.finalName}.jar"
                                   out="${project.build.directory}/${project.build.finalName}.jar" />
                        <rename logfile="${project.build.directory}/yguard.log.xml"
                                replaceClassNameStrings="true">
                            <property name="obfuscation-prefix" value="new.target.package"/>
                            <keep>
                                <class classes="private" methods="private" fields="private">
                                    <patternset>
                                        <include name="class.to.keep"/>
                                    </patternset>
                                </class>
                            </keep>
                        </rename>
                        <externalclasses>
                            <pathelement path="${mvn.classpath}" />
                        </externalclasses>
                    </yguard>
                </tasks>
            </configuration>
        </execution>
    </executions>
</plugin>