To develop an enterprise bean, you must provide the following files:
Deployment descriptor: An XML file that specifies information about the bean such as its persistence type and transaction attributes. The deploytool utility creates the deployment descriptor when you step through the New Enterprise Bean wizard.
Enterprise bean class: Implements the methods defined in the following interfaces.
Interfaces: The remote and home interfaces are required for remote access. For local access, the local and local home interfaces are required. See the section Defining Client Access with Interfaces (page 58). (Please note that these interfaces are not used by message-driven beans.)
Helper classes: Other classes needed ...