[P-279 of EJB3 In Action] states:
 "Note that the exact @JoinColumn vspecification could have been repeated for both the Bid.item and Item.bids persistent fields on
 either side of the relationship."
 [P-280 of EJB3 In Action] states:
 "The persistence provider will generate deployment-time errors if you specify @JoinColumn on both sides of a bidirectional one-tomany
 relationship."
 Aren;t these 2 statements contradictory?