code: void reloadConfigs() throws IOException, ParserConfigurationException,
        SAXException, ClassNotFoundException, RaidConfigurationException, JSONException {
      JSONObject json = (JSONObject) conf.getJsonConfig(configFileName);
      if (json != null) {
        reloadJSONConfigs(json);
      } else {
        reloadXmlConfigs();
      }
    }
docs: Updates the in-memory data structures from the config file. This file is
  expected to be in the following whitespace-separated format:
  
  <configuration>
  <policy name = RaidScanWeekly>
  <srcPath prefix="hdfs://hadoop.myhost.com:9000/user/warehouse/u_full/*"/>
  <parentPolicy> RaidScanMonthly</parentPolicy>
  <property>
  <name>targetReplication</name>
  <value>2</value>
  <description> after RAIDing, decrease the replication factor of the file to
  this value.
  </description>
  </property>
  <property>
  <name>metaReplication</name>
  <value>2</value>
  <description> the replication factor of the RAID meta file
  </description>
  </property>
  </policy>
  </configuration>
  
  Blank lines and lines starting with # are ignored.
  
  @throws IOException if the config file cannot be read.
  @throws RaidConfigurationException if configuration entries are invalid.
  @throws ClassNotFoundException if user-defined policy classes cannot be loaded
  @throws ParserConfigurationException if XML parser is misconfigured.
  @throws SAXException if config file is malformed.
  @throws JSONException
  @returns A new set of policy categories.