String winPath = "C:\\Users\\f.laudanum\\Documents\\My-Directory\\  ";
String cleanPath;

/* REGEXP pattern: '\\\s*' with doubled backslashes */
Pattern pattern = Pattern.compile("\\\\\\s*$");
Matcher match = pattern.matcher(winPath);

/* Call to find(0) triggers the pattern search from text's start*/
if (match.find(0)) {
    cleanPath = match.replaceAll("");
} else {
    cleanPath = winPath;
}