how to install missing jenkins plugins, when using gradlew?

When I try to run

gradlew 'task'

I get this following error message:

(I am obviously missing some jenkins plugins)

* What went wrong:
Error resolving plugin [id: 'com.terrafolio.jenkins', version: '1.3.2'].
> Could not resolve all dependencies for configuration 'detachedConfiguration1'.
  > Could not find org.jenkins-ci.plugins:job-dsl-core:1.42.
    Searched in the following locations:
      https://plugins.gradle.org/m2/org/jenkins-ci/plugins/job-dsl-
         core/1.42/job-dsl-core-1.42.pom
      https://plugins.gradle.org/m2/org/jenkins-ci/plugins/job-dsl-
         core/1.42/job-dsl-core-1.42.jar
    Required by:
      unspecified:unspecified:unspecified > com.terrafolio:gradle-jenkins-plugin:1.3.2

My task looks like this: (running a groovy script)

task testDeployOsb << {
javaexec {
  classpath = configurations.osb
  main = 'groovy.ui.GroovyMain'
  args = ["support-scripts/deployAlsb.groovy",
        "${buildDir}/deployment.groovy"]
  jvmArgs = ["-Dweblogic.MaxMessageSize=200000000",
           "-Dweblogic.CompleteT3MessageTimeout=480",
           "-Dweblogic.CompleteMessageTimeout=480",
           "-Dweblogic.wsee.transport.read.timeout=600000",
           "-Dweblogic.wsee.transport.connection.timeout=600000"]
  }
}

So how do I install said plugins?

Solution

You will have define at least one repository that can serve the external plugin. Maven Central seems to have it. Also the Gradle plugin portal hosts the plugin. You can find the notation for including it here.