Scopes in Oracle ADF

Mainly there are seven types of scopes in ADF.

None---view scope----Backing Bean Scope----Request scope----page flow scope----session scope---Application scope.  

Let us see those scopes in ascending order

No Scope:  When you created a managed bean without any scope. Then it is said to be with a scope called None. Objects with none scope are not visible on any JSF pages. A managed bean with None scope can be used by other managed beans

View Scope: The life time of a view scope is up to a particular page. When we navigate to other page the view id of a particular page get changes so that the view scope also changes. That means each page has its own view scope. View scope exists not only for the jspx pages but also for the page fragments .

Backing Bean Scope:  Backing bean scope are used by re usable components like Bounded Task flows with page fragments that are displayed as a regions on a page.

Request Scope: The life time of a request scope is up to sending the HTTP request and  getting the response  on the page. Request scope is  involved in performing server side forwarding requests but not in redirection mechanism.

To know the difference between Backing bean and request scope follow the link          Continue Reading>> 

Page flow scope: It  is also called as a Taskflow scope. Pageflow scope  is applicable for all the pages in the particular taskflow. The life time of a page flow scope is up to a task flow.

Session Scope: when an user opens an application in a browser window, and  then  session scope starts and it will be active up to that user closes the window. In middle more than one request scope may involve.

Application Scope: This scope is up to the application and it is  shared among all the users who are using the application.