5.1. Transparency
Generally it is objects of the domain object model that will be persisted by an application. These objects typically reference each other to the extent that the closure of referenced instances represents the entire contents of the data store. Whilst the application is running, its JVM will contain many transient instances. Most of these will be normal (non persistence-capable) objects. Some, however, will be (or will reference) instances of persistence-capable classes.
Each JDO persistence manager maintains an active cache of instances. As an application navigates a reference from one instance to another that is not in the cache, JDO loads the required instance into the cache
This is illustrated in Figure 5.1. A single JVM process ...
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