core/src/main/java/com/digitalpebble/stormcrawler/filtering/basic/BasicURLNormalizer.java
private String unmangleQueryString(String urlToFilter) {
        int firstAmp = urlToFilter.indexOf('&');
        if (firstAmp > 0) {
            int firstQuestionMark = urlToFilter.indexOf('?');
            if (firstQuestionMark == -1) {
                return urlToFilter.replaceFirst("&", "?");
            }
        }
        return urlToFilter;
    }
private String unmangleQueryString(String urlToFilter) {
        int firstAmp = urlToFilter.indexOf('&');
        if (firstAmp > 0) {
            int firstQuestionMark = urlToFilter.indexOf('?');
            if (firstQuestionMark == -1) {
                return urlToFilter.replaceFirst("&", "?");
            }
        }
        return urlToFilter;
    }
A common error to find is a query string that starts with an & instead of
a ? This will fix that error. So http://foo.com&a=b will be changed to
http://foo.com?a=b.

@param urlToFilter
@return corrected url