code: public static Inet6Address forIPv6String(String ipString) {
          requireNonNull(ipString);
  
          try{
              InetAddress parsed = forString(ipString);
  
              if (parsed instanceof Inet6Address)
                  return (Inet6Address) parsed;
  
          } catch(Exception ignored){}
  
          throw new IllegalArgumentException(format("Invalid IPv6 representation: %s", ipString));
      }
docs: Generates a new {@link Inet6Address} instance from the provided address. This will NOT do a dns lookup on the address if it
  does not represent a valid ip address like {@code InetAddress.getByName()}.
  
  If the provided string is an ipv4 "mapped" address ('ffff:x.x.x.x' this method will still generate a valid {@link Inet6Address}
  instance.