for reloading config.xml after edit

reload_config.groovy

import java.io.InputStream;
import java.io.FileInputStream
import java.io.File;
import javax.xml.transform.stream.StreamSource

def hudson = hudson.model.Hudson.instance;

Jenkins.instance.getAllItems(AbstractProject.class).each {job ->
  if (job.fullName.startsWith("YourFolder/")) {
    def configXMLFile = job.getConfigFile();
    def file = configXMLFile.getFile();

    InputStream is = new FileInputStream(file);

    job.updateByXml(new StreamSource(is));
    job.save();
  }
}