Ditto with Jenkins 2.19.1, Pipeline 2.4 and Pipeline Utility Steps 1.2.2

It used to work though with 2.19.1, Pipeline 2.4 and Pipeline Utility Steps 1.1.6

This sounds like http://stackoverflow.com/questions/34068168/groovy-binding-cannot-cast-object-with-class-custompackage-customclass-to-cla - could you try doing def mavenProject = readMavenPom(file: pom) instead of Model mavenProject ... and see if that helps?

Perhaps some other plugin is also loading maven-core. Probably maven-plugin.

I would not recommend importing org.apache.maven.model.* classes; use dynamic typing.

Or just avoid the readMavenPom step altogether, and use something like

def version = sh script: '''
mvn help:evaluate -Dexpression=project.version | perl -n -e 'print $1 if /^([0-9.]+(-SNAPSHOT)?)$/'
''', returnStdout: true

I have the same problem. def mavenProject works, but Model mavenProject throws the same exception.

Same too. This does not help writing libraries with proper type checks. Anyone has an idea for a fix or a workaround?

My advice remains to avoid these two steps.

Filed a PR to formally deprecate these steps.

Hi!

Which two steps are you refering to?

I definitely prefer

import org.apache.maven.model.Model Model mavenProject = readMavenPom(file: pom)

over

mvn help:evaluate -Dexpression=project.version | perl -n -e 'print $1 if /^([0-9.]+(-SNAPSHOT)?)$/' ''', returnStdout: true

It is more reliable, more readable and does not require (like any maven plugin execution) a lot of network activity in order to download / check all dependencies.
I have to admit, though, that I am OK to keep dynamic typing. It is just that it looks more like a bug that you avoid than something that you really want.

Could be closed in favor of https://issues.jenkins.io/browse/JENKINS-70717?

Probably.