public static String getHostName(InetAddress address) {
    String result = hostNames.get(address);
    if (result == null) {
      result = address.getHostName();
      hostNames.put(address, result);
    }
    return result;
  }
returns the host name for the given inet address, using a local cache of names to avoid dns
hits and duplicate strings
geode-core/src/main/java/org/apache/geode/internal/net/SocketCreator.java