Entity beans relationships question in the HFE

[Adri Smith]

From the HFE book, p432 q4:

Given the container-managed unidirectional relationship:

Foo(0-1) -> Bar(0-1)

and the object relations:

f1->b1
f2->b2

What will be true after the following code runs?

f2.setBar(f1.getBar())

How is it possible that 'b2.getFoo()==null' is one of the correct answers ? If the relationship is unidirectionnal this means we can call the method getBar() on the Foo beans but not the method getFoo() on the Bar Beans.

I took a look at the errata, nothing has been specified about this.

Thanks in advance for your help,
Adri