code: private static boolean isFormatCandidate(final String message) {
          char c;
          int n = message.length();
          while (n-- != 0) {
              c = message.charAt(n);
              if (c == '}' || c == '\'') {
                  return true;
              }
          }
          return false;
      }
docs: /*
  This will allow us determine whether a message might actually contain parameter placeholders.