1) InetAddressValidator.getInstance().isValidInet6Address(String inet6Address) returns true for value 0::ffff:192.168.1.1:192.168.1.1
I believe this is due to wrong comparison operand in line #166 of InetAddressValidator:
index > octets.length - 1 expression will never be true inside cycle
2) According to https://tools.ietf.org/html/rfc4291 IPv6 address that is IPv4-mapped must start with five zero octets followed by one ffff octet. Current implementation of InetAddressValidator does not check this. E.g. 1::2:192.168.1.1 is considered valid.