The Storing Objects in the Directory lesson discussed different ways in which Java objects (or rather information about Java objects) are stored in a directory. Each of that lesson's examples demonstrated that once the object is stored, you can simply use Context.lookup() to get a copy of the object back from the directory, regardless of what type of information was actually stored.
This is made possible by object factories. A brief discussion of how object factories are used by lookup() is included in the Lookups section of this lesson.
You can get the object back not only by using lookup(), but also when you list a context and when you search a context or its subtree. In all of these cases, object factories might be involved. This lesson describes also how these operations interact with object factories. Object factories are discussed in detail in the Object Factories lesson.