What is wrong with this code

#1

import java.util.*;
public class Main{
public static void fun(String in,String out,int i,ArrayList al){
//Base Case
int len = in.length();
if(i>=len){
al.add(out);
return;
}
//Recursive Case
String s = out+ (char)(Integer.parseInt(in.substring(i,i+1))+96);
fun(in,s,i+1,al);
if(i+2<=len){
String s1 = out+ (char)(Integer.parseInt(in.substring(i,i+1))*10+Integer.parseInt(in.substring(i+1,i+2))+96);
fun(in,s1,i+2,al);
}
}
public static void main(String args[]) {
Scanner sc = new Scanner(System.in);
String s = sc.next();
ArrayList al = new ArrayList<>();
fun(s,"",0,al);
System.out.println(al);
}
}

#2

ok i got. i solved by myself.

#3

I didd’t think about >26 values. thanks for replies

#4

man ! nice.
i was still debugging it.