Custom PMD rule with Gradle - gradle

Question

I would like to use the gradle PMD plugin in an enterprise project which is built with gradle.
I have a pmd_rules.xml file which already works, but I can't add own java rules (I get a class not found exception). I followed the tutorial on it's website.
Where do I have to put my own rules so they get recognized by gradle and PMD? Has somebody already done something like that?
pmd.gradle:
apply from: rootProject.file("core/modules.gradle"), to : ext
if(project.name in (modules["modules"] +modules["modules"])){
apply plugin: 'pmd'
pmd {
ignoreFailures = true
ruleSetFiles = rootProject.files("../repo/pmd_rules.xml")
sourceSets = [sourceSets.main,sourceSets.test]
targetJdk = org.gradle.api.plugins.quality.TargetJdk.VERSION_1_7
ruleSets = []
toolVersion = "5.0.5"
}
}

Answer 1

tasks.withType(Pmd) {
pmdClasspath += file("path/to/rules.jar")
}

Answer 2

For latest Gradle pmd plugin you need to do the following things:
Add your library with pmd rules to plugin classpath
https://github.com/dgroup/arch4u-pmd#gradle-buildgradle
dependencies {
...
pmd "io.github.groupid:libid:versionid"
pmd "commons-io:commons-io:2.11.0"
...
}
Include ruleset from your lib
https://github.com/dgroup/arch4u-pmd#include-arch4u-pmd-rules-into-your-existing-custom-ruleset
<?xml version="1.0"?>
<ruleset name="pmd ruleset with your rules">
...
<rule ref="io/github/path-to-ruleset-from-your-lib.xml"/>
...
</ruleset>
or define particular rules in your
https://github.com/dgroup/arch4u-pmd#reconfigure-a-rule
<?xml version="1.0"?>
<ruleset name="pmd ruleset with your rules">
...
<!-- 2. Reconfigure rule with expected property -->
<rule name="RuleFromYourLibrary" class="io.github.RuleFromYourLibrary">
<priority>3</priority>
<properties>
...
</properties>
</rule>
...
</ruleset>