How to connect Facebook, Twitter & Google accounts in Java (Spring MVC)

I'm going through the features of social auth (http://code.google.com/p/socialauth/) & wondering if this is the best thing for my requirement. Please guide.

My web application currently has it's own login mechanism(native). But I'm planning to do the following:

1. Login through Facebook(F), Twitter(T) and Google(G) options
2. After login (either through F,T,G or native login), I want to give user the option of selecting F friends, T followers or G contacts (in a textbox with autosuggest facility)

So my doubt is: (social auth says that "..currently Facebook, Twitter and LinkedIn do not provide email addresses. UPDATE: Hotmail has stopped providing email addresses.") So although I'll have a list of followers, friends or contacts will I be able to notify them once my user selects and submits his form?

Will it be through F,T or G respectively(through status updates, tweets or email?)

Moreover, I've one more scenario: E.g. the user has logged in using Facebook. Now I want the user to be able to link her Twitter and Google account too. Can socialauth provide that? If yes, how would I handle multiple profile objects of the same user?

Please guide or suggest any other library. My application is in Spring MVC.

Or shall I use Spring Social?

Since your application uses Spring-MVC you should try Spring Social. It would be best for your application.