expellingHttpSession

expellingHttpSession refers to the process of terminating an active user session managed by the HTTP protocol. In web applications, an HttpSession is created when a user first interacts with the server and persists for a certain period, allowing the server to maintain state for that user across multiple requests. This state can include user preferences, login status, or shopping cart contents.

There are several ways an HttpSession can be "expelled" or invalidated. The most common method is explicit session invalidation by the application. This typically occurs when a user logs out, explicitly ending their session. The server then destroys the HttpSession object and removes any associated data. Another common scenario is session timeout. If a user remains inactive for a predefined period, the server automatically invalidates the HttpSession to conserve resources and enhance security.

Client-side actions can also lead to session termination. Clearing browser cookies, specifically the session cookie that identifies the HttpSession, will effectively end the session from the server's perspective upon the next request. Furthermore, if the server restarts or the application is redeployed, existing sessions are typically lost and new ones will be created. The underlying mechanism involves a unique session identifier, often stored in a cookie, which the server uses to associate incoming requests with the correct HttpSession. Expelling the session means removing this association and discarding the session data.