Your enterprise application is going to consist of hundreds of objects: entity objects, view objects, application modules, task flows, page fragments, and many others. It is imperative that you keep everything in a logical structure. A good structure also allows you to partition work between the many people who will be working on your team, and ensures that everyone can find what they need.
Remember from Chapter 3, Getting Organized, we divided all but the simplest applications into a number of workspaces. In recent versions, JDeveloper has unfortunately started using the Word application for what used to be called workspace. While it is correct that you need a workspace to build an application, the opposite is not true—you will have many workspaces that are not applications.