When none of the previous scopes meet your application needs, you have to pay attention to the JSF 2 custom scope. Most likely, you will never want to write a custom scope, but if it is necessary, then, in this section, you can see how to accomplish this task.

In order to implement a custom scope, let's suppose that you want to control the life cycle of several beans that live in the application scope. Normally they live as long as the application lives, but you want to be able to add/remove them from the application scope at certain moments of the application flow. Of course, there are many approaches to do that, but remember that we look for a reason to implement a custom scope; therefore, we will try to write a custom scope nested in the application scope that will allow us to add/remove a batch of beans. Creating and destroying the scope itself will...