Issue
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You are writing a groovy script which uses a particular library, and the script is throwing a
groovy.lang.MissingMethodException. -
You are migrating jobs from one Jenkins instance to another. When your job runs, you see 'Unable to resolve class org.foo'.
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You need to know which library is providing the class you are using.
Resolution
Jenkins has a complex, modular architecture which means each plugin gets its own ClassLoader which altogether form a hierarchy rooted at the Jenkins core ClassLoader. To locate the plugin which can load a specific class use the following Groovy script:
String className = "<enter fully qualified class name here>"
def clazzResource = className.replaceAll("\\.", "/") + ".class"
println "Looking for: ${clazzResource}\n"
Jenkins.instance.pluginManager.activePlugins.forEach { PluginWrapper plugin ->
def c = plugin.classLoader.getResources(clazzResource)
if (c.hasMoreElements()) {
println "Found in ${plugin}"
println Collections.list(c).join("\n") + "\n"
}
}
println("Plugin order:")
Jenkins.instance.pluginManager.activePlugins.each{ it -> println(" " + it.shortName) }
return
For example, let’s say I would like to know which plugin is providing the snakeyaml Yaml utilities. Go to the Jenkins Script Console, paste the above script and replace the placeholder like this:
String className = "org.yaml.snakeyaml.Yaml"
You should see something similar as a result:
Looking for: org/yaml/snakeyaml/Yaml.class Found in Plugin:blueocean-rest-impl jar:file:/tmp/jenkins/plugins/blueocean-rest-impl/WEB-INF/lib/snakeyaml-1.10.jar!/org/yaml/snakeyaml/Yaml.class Found in Plugin:kubernetes jar:file:/tmp/jenkins/plugins/kubernetes/WEB-INF/lib/snakeyaml-1.15.jar!/org/yaml/snakeyaml/Yaml.class ...