You may express a query in SQL, using createNativeQuery() and let Hibernate take care mapping from JDBC result sets to business objects. Use the @SqlResultSetMapping (please see the Hibernate Annotations reference documentation on how to map a SQL resultset mapping) or the entity mapping (if the column names of the query result are the same as the names declared in the entity mapping; remember that all entity columns have to be returned for this mechanism to work):

@SqlResultSetMapping(name="getItem", entities = 
        @EntityResult(entityClass=org.hibernate.ejb.test.Item.class, fields= {
            @FieldResult(name="name", column="itemname"),
            @FieldResult(name="descr", column="itemdescription")
        })
)

Query q = em.createNativeQuery("select name as itemname, descr as itemdescription from Item", 
    "getItem");
item = (Item) q.getSingleResult(); //from a resultset

Query q = em.createNativeQuery("select * from Item", Item.class);
item = (Item) q.getSingleResult(); //from a class columns names match the mapping