JAAS Principal Arayüzü

Giriş
Şu satırı dahil ederiz.

import javax.security.Principal;

Açıklaması şöyle. Subject nesnesi içinde saklanırlar. Bence ismi Privilege olsaydı daha iyi olurdu. Bu Subject'in şu işi yapmaya hakkı var mı sorusuna cevap veriyor

A Subject is a Java object that represents a single entity, such as an individual. A single Subject can have a number of associated identities, each of which is represented by a Principal object. So, say a single Subject represents an employee who requires access to both the e-mail system and the accounting system. That Subject will have two Principals, one associated with the employee's user ID for e-mail access and the other associated with his user ID for the accounting system.

Principals are not persistent, so they must be added to the Subject each time the user logs in. A Principal is added to a Subject as a part of a successful authentication procedure. Likewise, a Principal is removed from the Subject if the authentication fails. Regardless of the success or failure of authentication, all Principals are removed when the application performs a logout.