public void rememberExactError(Location location) {
        if (location.getColumn() < 0 || location.getLine() < 0) {
            return;
        }
        exactErrors.add(location);
    }
@see org.xml.sax.ContentHandler#characters(char[], int, int)
@see java.lang.StringBuffer#append(char[], int, int)
src/nu/validator/source/SourceCode.java