Are there any exceptions to the co-location optimization for EJBs?

1) What if an entity bean instance that the call needs is on another
server? Will it migrate the entity bean rather than making a remote
call to the server on which it resides?

2) What if all of the instances in a pool of session beans are
currently in use? Will it block rather than try another server

3) What if there is no room on an execute queue?

-- Les Walker