Jenkins Groovy Scripts: Update Groovy from 2.2.1/Default to Groovy 2.3 builders

update_groovy_build_version.groovy

import jenkins.model.*

for(item in Jenkins.instance.items) {
  if (!(item instanceof com.cloudbees.plugins.flow.BuildFlow)
     	&& !(item instanceof hudson.maven.MavenModuleSet)
        && !(item instanceof org.jenkinsci.plugins.workflow.job.WorkflowJob)) {
    for (builder in item.builders) {
      if(builder instanceof hudson.plugins.gradle.Gradle) {
        println(item.name)
    	println(builder)
        println(builder.gradleName)
        String gradleName = builder.gradleName
        if (gradleName == "(Default)" || gradleName == "Gradle-2.2.1") {
          println("Need to update!!") 
          println(builder.properties)
          hudson.plugins.gradle.Gradle newGradle = new hudson.plugins.gradle.Gradle(
            builder.properties.description,
            builder.properties.switches,
            builder.properties.tasks,
            builder.properties.rootBuildScriptDir,
            builder.properties.buildFile,
            "Gradle-2.3",
            builder.properties.useWrapper,
            builder.properties.makeExecutable,
            builder.properties.fromRootBuildScriptDir,
            builder.properties.useWorkspaceAsHome)
          println(newGradle.properties)
          println(item.buildersList)
          item.buildersList.replace(newGradle)
          println(item.buildersList)
        }
        println('\n')
      }
    }
  }
}

Need to make this more generic - too specific at this time but does the job!