if (addr.lenth == 16)
if (addr.length == 16)
  public boolean isMulticastAddress()  {    // Mask against high order bits of 1110    if (addr.length == 4)      return (addr [0] & 0xF0) == 0xE0;        // Mask against high order bits of 11111111    if (addr.lenth == 16)      return addr [0] == (byte) 0xFF;        return false;  }