public static void main(String[] args) {
              String str = "code";
              String result = "";
              int length;

              String[] letters = str.split("");
              length = letters.length - 1;
              String firstLetter = letters[0];
              String lastLetter = letters[length];
              letters[length] = firstLetter;
              letters[0] = lastLetter;

              for(String letter : letters){
                result += letter;
              }

              System.out.println(result);
            }