docs: protected static synchronized String resolveDefaultHostName(String cfgDefaultHost) {
          if (resolvedDefaultHostName == null || !cfgDefaultHost.equals(defaultHostName)) {
              // remember what was configured. This might be replaced by localhost if
              // the specified address was unresolvable.
              defaultHostName = cfgDefaultHost;
  
              if (HostNameUtils.validLocalHostName(defaultHostName)) {
                  resolvedDefaultHostName = defaultHostName;
              } else {
                  // If the default host name can not be resolved back to a NIC on this machine,
                  // issue a warning message, and use localhost.
                  Tr.warning(tc, "unresolveableDefaultHost", defaultHostName);
                  resolvedDefaultHostName = HttpServiceConstants.LOCALHOST;
              }
          }
          return resolvedDefaultHostName;
      }