This week's book giveaway is in the OCAJP forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide 1Z0-808 and have Jeanne Boyarsky & Scott Selikoff on-line! See this thread for details.
No, there isn't a way to get that information. It is for security reasons that it is not available.
You will need either a RecordStore to store the userID. So you can make an install where you then run the applicaiton, enter in the UserID, which is stored in the RecordStore, then passed when trying to log into the server. Or have a Login Screen when the app starts that the user enters the userID and Password.