A directed graph data structure consisting of objects linked to other related or associated objects. The links in a graph of persistent objects can be references in persistent fields, relationships, or memberships in persistent collections.
An object is said to reference the objects held in its fields. This collection of objects forms an object graph. The memory manager actually migrates the object graphs held in static variables; that is, it migrates not only the objects held in static fields, but the objects that those objects reference, and so on.