assertEquals(
          "checking '" + validCompatAddress + "'",
          compat,
          InetAddresses.getCompatIPv4Address((Inet6Address) ip));
    }
  }

  public void testMappedIPv4Addresses() throws UnknownHostException {
    /*
     * Verify that it is not possible to instantiate an Inet6Address
     * from an "IPv4 mapped" IPv6 address.  Our String-based method can