Incrementing a string

How do I take an input and increment each letter by one e.g "ABC" to "BCD" in Java. I have attempted below to try and change the string to an int and then increase the value by 1.

import java.util.Scanner; public class w7q3 {

public static void main(String[] args) {
    Scanner in = new Scanner (System.in);
    String str ="";
    int A = 0;

    System.out.println ("Enter String");

    str = in.nextLine(); 

     int num = Integer.parseInt(str);

    num= num +1;


    System.out.println(str);
}


}