Java Code to validate email addresses

public final class EmailUtil
{
    /**
     * http://www.regular-expressions.info/email.html
     */
    @RegEx
    private static final Pattern EMAIL_PATTERN = Pattern.compile(
            "^[A-Z0-9._%+\\-#']+@[A-Z0-9.-]+\\.(?:[A-Z]{2}|com|org|net|edu|gov|mil|biz|info|mobi|name|aero|asia|jobs|museum)$", Pattern.CASE_INSENSITIVE);

    /**
     * Validate an email address.
     *
     * @param email the email to validate.
     * @param hostCache OPTIONAL cache of host names
     * @throws InvalidDataException details of the issue found.
     */
    public static void validate(final String email, final Map<String, String> hostCache) throws InvalidDataException
    {
        String invalidStrings[] =
        {
            "..", ".@"
        };
        for (String illegal : invalidStrings)
        {
            if (email.contains(illegal))
            {
                throw new InvalidDataException("email " + email + " may not contain '" + illegal + "'");
            }
        }

        Matcher m = EMAIL_PATTERN.matcher(email.trim());
        if (m.matches() == false)
        {
            throw new InvalidDataException(email + " invalid email");
        }

        String[] split = email.split("@");

        if (split.length != 2)
        {
            throw new InvalidDataException("no @ symbol");
        }
        String tmpHost = split[1];
        String message = checkMX(tmpHost, null);
        if (message != null)
        {
            throw new InvalidDataException(message);
        }
    }

    /**
     * check the MX record
     *
     * @param hostName host to check
     * @param hostCache OPTIONAL cache of host names
     * @return message if NOT valid otherwise NULL
     */
    public static String checkMX(final String hostName, final Map<String, String> hostCache)
    {
        String message = null;
        if (hostCache != null)
        {
            message = hostCache.get(hostName);
        }

        if (message == null)
        {
            @SuppressWarnings("UseOfObsoleteCollectionType")
            Hashtable env = new Hashtable();
            env.put("java.naming.factory.initial",
                    "com.sun.jndi.dns.DnsContextFactory");
            try
            {
                DirContext ictx = new InitialDirContext(env);
                Attributes attrs =
                        ictx.getAttributes(hostName, new String[]
                {
                    "MX"
                });
                Attribute attr = attrs.get("MX");
                if (attr == null)
                {
                    message = "no MX record for " + hostName;
                }
                else if (attr.size() > 0)
                {
                    message = "";
                }
                else
                {
                    message = "no MX record for " + hostName;
                }
            } catch (NamingException e)
            {
                message = e.getMessage();
            }

            if (hostCache != null)
            {
                hostCache.put(hostName, message);
            }
        }

        if (message == null || message.isEmpty())
        {
            return null;
        }

        return message;
    }
}