15.4. Associations

You may easily specify constraints upon related entities by navigating associations using createCriteria().
List cats = sess.createCriteria(Cat.class)
    .add( Restrictions.like("name", "F%") )
        .add( Restrictions.like("name", "F%") )
note that the second createCriteria() returns a new instance of Criteria, which refers to the elements of the kittens collection.
The following, alternate form is useful in certain circumstances.
List cats = sess.createCriteria(Cat.class)
    .createAlias("kittens", "kt")
    .createAlias("mate", "mt")
    .add( Restrictions.eqProperty("kt.name", "mt.name") )
(createAlias() does not create a new instance of Criteria.)
Note that the kittens collections held by the Cat instances returned by the previous two queries are not pre-filtered by the criteria! If you wish to retrieve just the kittens that match the criteria, you must use a ResultTransformer.
List cats = sess.createCriteria(Cat.class)
    .createCriteria("kittens", "kt")
        .add( Restrictions.eq("name", "F%") )
Iterator iter = cats.iterator();
while ( iter.hasNext() ) {
    Map map = (Map) iter.next();
    Cat cat = (Cat) map.get(Criteria.ROOT_ALIAS);
    Cat kitten = (Cat) map.get("kt");