code: public static String convertSpecialStringTags(String pValue) {
          if ("[null]".equals(pValue)) {
              // Null marker for get requests
              return null;
          } else if ("\"\"".equals(pValue)) {
              // Special string value for an empty String
              return "";
          } else {
              return pValue;
          }
      }
docs: For GET requests, where operation arguments and values to write are given in
  string representation as part of the URL, certain special tags are used to indicate
  special values:
  
  <ul>
  <li><code>[null]</code> for indicating a null value</li>
  <li><code>""</code> for indicating an empty string</li>
  </ul>
  
  This method converts these tags to the proper value. If not a tag, the original
  value is returned.
  
  If you need this tag values in the original semantics, please use POST requests.
  
  @param pValue the string value to check for a tag
  @return the converted value or the original one if no tag has been found.