4 6 7 8 9 10 11 12 13 } public static void main(String[] args) { String str = "test string"; String reversedStr = reverse(str); System.out.println(reversedStr); // expect result: gnirts tset } public static String reverse(String str) { } Figure 3: Reversing a String with Recursion Please finish the reverse() method to reverse the string, excepted result: gnirts tset. (You should use recursion to solve this problem. You can use other programming language)