The application scope lives as long as the web application lives.
An application scope extends the session scope with the shared state across all users' interactions with a web application; this scope lives as long as the web application lives. Since the beans in the application scope lives until the application shuts down (or they are programmatically removed), we can say that this scope lives most. More precisely, objects settled on the application scope can be accessed from any page that is part of the application (for example, JSF, JSP, and XHTML).
Note
The application scope should be used only for data that is safe to be shared. Since an application scoped bean is shared by all users, you need to be sure that the bean has an immutable state or you need to synchronize access.
Usually, application scope objects are used as counters, but they can be used for many other tasks, such as initializations and navigations. For example, the application scope can be used to count...