I would like to know how I should change the criteria at the page 264 to retrieve all the Items that do not have any Bids or have bids under 100$?

The mapping between item and bid is one-to-many and the criteria given in p. 264 is

List results = session.createCriteria(Item.class)
.add( Expression.like("description", "gc", MatchMode.ANYWHERE) )
.createCriteria("bids")
.add( Expression.gt("amount", new BigDecimal("100") ) )
.list();

I am specially interested how to test if parent in one2many relation does not have any children.

there is no support for subselects in the criteria query API at this time, so you could use Expression.sql().

I am +1 on adding a new Expression.empty() criterion, so please add a request for this to JIRA. Thanks.

Feature request added to the JIRA