web

zero or more 

Specifies the application’s web tier configuration. 

pass-by-reference

zero or one 

Determines whether EJB modules use pass-by-value or pass-by-reference semantics. 

unique-id

zero or one 

Contains the unique ID for the application. 

security-role-mapping

zero or more 

Maps a role in the corresponding J2EE XML file to a user or group. 

realm

zero or one 

Specifies an authentication realm.