code: private static String calculateStringToSignV1(Map<String, String> parameters) {
          StringBuilder data = new StringBuilder();
          Map<String, String> sorted = new TreeMap<String, String>(String.CASE_INSENSITIVE_ORDER);
          sorted.putAll(parameters);
          Iterator<Entry<String, String>> pairs = sorted.entrySet().iterator();
          while (pairs.hasNext()) {
              Map.Entry<String, String> pair = pairs.next();
              data.append(pair.getKey());
              data.append(pair.getValue());
          }
          return data.toString();
      }
docs: Calculate String to Sign for SignatureVersion 1
  
  @param parameters
  request parameters
  @return String to Sign