package com.test;

public class TestString {

 public static void main(String[] args) {

  String s = "Hello";  s = reverse(s, 2, 4);  System.out.println(s); }

 public static String reverse(String s, int f, int t) {

  char[] c = new char[s.length()];  for (int i = 0; i < s.length(); i++) {    if (f - 1 == i || i == t - 1) {     c[i] = s.charAt(t - (2 - f) - i);   } else {     c[i] = s.charAt(i);   }  }  return String.valueOf(c); }}