Some other things to think about.
* Your comment says you are expecting the SSN in the form nnn-nn-nnnn, but then you don't prompt for that.
* You don't check whether in input is 11 in length.
* firstgroup4 and secondgroup3 should only ever be '-'.
* Checking for Character.isLetter() is not the same as checking for a non-digit character.
* The values in the substring() method at lines 71 through 81 don't seem right. See the documentation on
substring.