Java Persistence with Hibernate

12.1. Transitive persistence

Real, nontrivial applications work not only with single objects, but rather with networks of objects. When the application manipulates a network of persistent objects, the result may be an object graph consisting of persistent, detached, and transient instances. Transitive persistence is a technique that allows you to propagate persistence to transient and detached subgraphs automatically.

For example, if you add a newly instantiated Category to the already persistent hierarchy of categories, it should become automatically persistent without a call to save() or persist(). We gave a slightly different example in chapter 6, section 6.4, "Mapping a parent/children relationship," when you mapped a parent/child relationship ...