Make The String Great

1class Solution {
2    public String makeGood(String s) {
3        StringBuilder sb = new StringBuilder(s);
4
5        for (int i = 0; i < sb.length() - 1; )
6        {
7            int diff = sb.codePointAt(i) - sb.codePointAt(i + 1);
8            if (diff == 32 || diff == -32)
9            {
10                sb.delete(i, i + 2);
11                if (i > 0)
12                {
13                    i--;
14                }
15            }
16            else
17            {
18                i++;
19            }
20        }
21
22        return sb.toString();
23    }
24}