public static String normalizeUnicode(final String s) {
        if (s == null) {
            return null;
        }
        String decoded;
        try {
            decoded = IDN.toUnicode(s);
        } catch (final IllegalArgumentException ignore) {
            decoded = s;
        }
        return normalize(decoded);
    }
Decodes to Unicode and normalizes the given DNS name.
@since 5.5
httpclient5/src/main/java/org/apache/hc/client5/http/utils/DnsUtils.java