docs: @Nullable
    public static String getWithoutForbiddenChars (@Nullable final String s)
    {
      if (s == null)
        return null;
  
      final StringBuilder aCleanValue = new StringBuilder (s.length ());
      int nForbidden = 0;
  
      for (final char c : s.toCharArray ())
        if (isForbiddenParamValueChar (c))
          nForbidden++;
        else
          aCleanValue.append (c);
  
      if (nForbidden == 0)
      {
        // Return "as-is"
        return s;
      }
  
      if (LOGGER.isWarnEnabled ())
        LOGGER.warn ("Removed " + nForbidden + " forbidden character(s) from a request parameter value!");
  
      return aCleanValue.toString ();
    }