a question regarding chap 9 ejb3 in action

[Ash More']

i am bit puzzled about the chapter 9 listing 9.1

public Item undoItemChanges(Item item) {
entityManager.refresh(entityManager.merge(item));
return item;
}
public void deleteItem(Item item) {
entityManager.remove(entityManager.merge(item));
} 

shouldnt the above code be like this:

public Item undoItemChanges(Item item) {
entityManager.refresh(item);
return item;
}
public void deleteItem(Item item) {
entityManager.remove(item);
}

in the code mentioned in the book , why is entityManager.merge(item) used as a parameter to methods refresh and remove??
if entityManager.merge(item) is used inside the refresh method , then merge will first update the database and then refresh will bring the newly updated value back , so will undoItemChanges work??

what does entityManager.merge(item) actually return?? the instance with old values or the instance of item with modified values??


any help would be really appreciated
[ May 03, 2008: Message edited by: Ash More' ]

[Ash More']

ok,
i was running too ahead of myself. the explanation has been given through the rest of the chapter. i got the answer to my queries.