public byte []
getHexString() throws IOException {
	String next = _getIdentifier("a hex string");
	byte [] array = base16.fromString(next);
	if (array == null)
		throw exception("invalid hex encoding");
	return array;
}
Gets the next token from a tokenizer and decodes it as hex.
@return The byte array containing the decoded string.
@throws TextParseException The input was invalid.
@throws IOException An I/O error occurred.
src/main/java/core/org/xbill/DNS/Tokenizer.java