ruboto.rb

class SimpleIntentService < Java::AndroidApp::IntentService
  def onHandleIntent(intent)
    android.util.Log.v 'Punch', "Handling intent"
    sleep 5
  end
end

class QuickStartActivity
  def onCreate(bundle)
      msgIntent = android.content.Intent.new(self, android.app.IntentService)
      startService(msgIntent)
  end
end

https://developer.android.com/training/run-background-service/send-request.html