In J2EE agents, the agent realm component manages authorization. A realm is a means for a J2EE-compliant application server to provide information about users, groups, and access control to applications deployed on it. It is a scope over which security policy is defined and enforced.
The server is configured to use a specific realm for validation of users and their roles, when attempts are made to access resources. By default, many application servers ship with a number of realm implementations, including the default File Based as well as LDAP, NT, UNIX, and Relational Database Management System (RDBMS). The agent realm component implements the server’s realm interface, and allows user and role information to be managed by the Access Manager deployment. The agent realm component makes it possible to provide granular role-based authorization of J2EE resources to users who have been authenticated by the agent filter component.