code: private static long getNetworkAddressCacheTtlNanos(boolean isAndroid) {
      if (isAndroid) {
        // on Android, ignore dns cache.
        return 0;
      }
  
      String cacheTtlPropertyValue = System.getProperty(NETWORKADDRESS_CACHE_TTL_PROPERTY);
      long cacheTtl = DEFAULT_NETWORK_CACHE_TTL_SECONDS;
      if (cacheTtlPropertyValue != null) {
        try {
          cacheTtl = Long.parseLong(cacheTtlPropertyValue);
        } catch (NumberFormatException e) {
          logger.log(
              Level.WARNING,
              "Property({0}) valid is not valid number format({1}), fall back to default({2})",
              new Object[] {NETWORKADDRESS_CACHE_TTL_PROPERTY, cacheTtlPropertyValue, cacheTtl});
        }
      }
      return cacheTtl > 0 ? TimeUnit.SECONDS.toNanos(cacheTtl) : cacheTtl;
    }
docs: Returns value of network address cache ttl property if not Android environment. For android,
  DnsNameResolver does not cache the dns lookup result.