About Question com.enthuware.ets.scjp.v6.1.754 :

[normc]

Sorry for being such a pain in the arse with so many questions...really getting my 20 bucks worth ha ha.

Although sb is not shared among multiple threads, a Person instance could be shared, thus allowing concurrent calls in the toString() method. Wrong?

[admin]

Concurrent calls to Person instance will not cause any trouble in the given code because there are no public setters for the fields and the fields are private.

HTH,
Paul.

[cosmindumy]

I see the same problem.
Didn't try in IDE but probably different threads will get "nullnull-null" or "null-nullnull". Is this correct for this question?

[admin]

What makes you think that it will get "nullnull-null" or "null-nullnull"?
-Paul.