android/guava/src/com/google/common/net/InetAddresses.java
public static Inet4Address getIsatapIPv4Address(Inet6Address ip) {
    checkArgument(isIsatapAddress(ip), "Address '%s' is not an ISATAP address.", toAddrString(ip));

    return getInet4Address(Arrays.copyOfRange(ip.getAddress(), 12, 16));
  }
public static Inet4Address getIsatapIPv4Address(Inet6Address ip) {
    checkArgument(isIsatapAddress(ip), "Address '%s' is not an ISATAP address.", toAddrString(ip));

    return getInet4Address(Arrays.copyOfRange(ip.getAddress(), 12, 16));
  }
Returns the IPv4 address embedded in an ISATAP address.

@param ip {@link Inet6Address} to be examined for embedded IPv4 in ISATAP address
@return {@link Inet4Address} of embedded IPv4 in an ISATAP address
@throws IllegalArgumentException if the argument is not a valid IPv6 ISATAP address