This figure shows the flow of subject propagation, or identity propagation. First, a Web client establishes its identity by passing the user name and password to a servlet within a J2EE container. The servlet then uses that identity to communicate with other EJBs and servlets within the same J2EE container or, through caller ID, in other J2EE containers. After authentication, the EJBs and servlets can communicate with the components of the enterprise information system tier, such as a messaging system, database, or ERP and SAP applications (all shown).

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