code: public void addDateRangeFilter(String key, DateRange dateRange) {
  
          JsonObject opObj = new JsonObject();
  
          if (dateRange.getFromDate() != null) {
              String dateGtString = BoxDateFormat.format(dateRange.getFromDate());
              //workaround replacing + and - 000 at the end with 'Z'
              dateGtString = dateGtString.replaceAll("(\\+|-)(?!-\\|?!\\+)\\d+$", "Z");
              opObj.add("gt", dateGtString);
          }
          if (dateRange.getToDate() != null) {
              String dateLtString = BoxDateFormat.format(dateRange.getToDate());
              //workaround replacing + and - 000 at the end with 'Z'
              dateLtString = dateLtString.replaceAll("(\\+|-)(?!-\\|?!\\+)\\d+$", "Z");
              opObj.add("lt", dateLtString);
          }
  
          this.filtersList.add(key, opObj);
      }
docs: Set a filter to the filterList, example: key=documentNumber, gt : "", lt : "".
  @param key the key that the filter should be looking for.
  @param dateRange the date range that is start and end dates