Sany,
The whole point of the question is to
test your knowledge of what happens when you take members of one association and put it in another one. In this case, since it's a 1-to-1 association, taking b1 and associating it with f2 disassociates b2 from any f-object and disassociates f1 from any b-object.
So, f1.getBar() == null, f2.getBar() == b1. B-objects don't have any links to their associated f-object, so b2.getFoo() doesn't mean anything. B-objects also don't have any association with other B-objects, so b1.getBar() doesn't have any meaning either.
In the end, the answer is A. B and C are false because they would be syntactically invalid given the unidirectional nature and structure of the question. D is incorrect since A is correct. Therefore, only A is correct.
Nathaniel Stodard<br />SCJP, SCJD, SCWCD, SCBCD, SCDJWS, ICAD, ICSD, ICED