code: def _list_request(self):
          
          try:
              # https://jolokia.org/reference/html/protocol.html
              #
              # A maxDepth of 1 restricts the return value to a map with the JMX
              # domains as keys. The values of the maps don't have any meaning
              # and are dummy values.
              #
              # maxCollectionSize=0 means "unlimited". This works around an issue
              # prior to Jolokia 1.3 where results were truncated at 1000
              #
              url = "http://%s:%s/%s%s?maxDepth=1&maxCollectionSize=0" % (
                  self.config['host'],
                  self.config['port'],
                  self.jolokia_path,
                  self.LIST_URL)
              # need some time to process the downloaded metrics, so that's why
              # timeout is lower than the interval.
              timeout = max(2, float(self.config['interval']) * 2 / 3)
              with closing(urllib2.urlopen(self._create_request(url),
                                           timeout=timeout)) as response:
                  return self._read_json(response)
          except (urllib2.HTTPError, ValueError) as e:
              self.log.error('Unable to read JSON response: %s', str(e))
              return {}
docs: Returns a dictionary with JMX domain names as keys