A business component project differs from other JDeveloper projects by having a .jpx file. The .jpx file is an XML file that defines the project as a business component project. A business component project contains the following folders and files:

Deployment folder - The Deployment folder contains deployment profiles (.prf files). When you create a new deployment profile, it is placed here by default.
Packages - A business component package is similar to, and treated the same way as, a Java package.
Business components - This is where your application modules, associations, domains, entitiy objects, view links and view objects reside. The business components are represented by a Java file and an XML file.
JPX file - The .jpx file is an XML file that defines the project as a business component project.
Other files - your business component project may contain any number of files, from custom Java or XML files, to TypeMaps, etc.