RC4 encryption java

Question

Hi there I am trying to implement the RC4 algorithm in Java. I found this code as an example that help me to understand the idea:

public class RC4 {
  privat         


        

Answer 1

1) int array: probably because Java doesn't support unsigned bytes.

2) Null exception: I counted line 12 being this one: S[i] = i; It looks like the S array is not being constructed before it's used.