Jenkins list all plugins with version number

getPluginsJson.groovy

import groovy.json.JsonBuilder
import groovy.json.JsonOutput

def json = new JsonBuilder().plugins {}
def plugins = jenkins.model.Jenkins.instance.getPluginManager().getPlugins()

for (p in plugins){
  j = new JsonBuilder().plugin {
    "${p.getShortName()}" "${p.getVersion()}"
  }
  json.plugins << j.plugin
}

println(new JsonBuilder(json.plugins).toPrettyString())