code: public static String getStormZookeepers(final Map<String, Object> stormConfig) {
          final Object stormZookeepers = stormConfig.get(Config.STORM_ZOOKEEPER_SERVERS);
          final Object stormZookeepersPort = stormConfig.get(Config.STORM_ZOOKEEPER_PORT);
          if (stormZookeepers instanceof List && stormZookeepersPort instanceof Number) {
              // join the servers and the port together to a single zookeeper connection string for kafka
              final StringBuilder zookeepers = new StringBuilder();
              final int port = ((Number) stormZookeepersPort).intValue();
  
              for (final Iterator<?> iterator = ((List) stormZookeepers).iterator(); iterator.hasNext(); ) {
                  zookeepers.append(String.valueOf(iterator.next()));
                  zookeepers.append(':');
                  zookeepers.append(port);
                  if (iterator.hasNext()) {
                      zookeepers.append(',');
                  }
              }
              return zookeepers.toString();
          }
  
          // no valid zookeeper configuration found
          return null;
      }
docs: Creates a zookeeper connect string usable for the kafka configuration property {@code "zookeeper.connect"} from
  storm's configuration map by looking up the {@link org.apache.storm.Config#STORM_ZOOKEEPER_SERVERS} and
  {@link org.apache.storm.Config#STORM_ZOOKEEPER_PORT} values. Returns null when this procedure fails.
  
  @param stormConfig Storm's configuration map.
  @return A zookeeper connect string if it can be created from storm's config or null.