jgss

I'm working a web appliaction with SSO based on the Windows domain login, for this purpose I have chosen to validate Kerberos tickets. But now I'm facing a problem for which I can't find a solution. I manage to validate a ticket without exceptions, but when I'm trying to get the userName, NullPointerException is thrown, because the username is null and I don't know where is problem. Why is user name null if I don't get any exception during the validation? How I get userName: String clientName = gssContext.getSrcName().toString(); I create my client based on this: Using GSSManager to validate a