What is Managed Bean?
JavaBean objects managed by a JSF implementation are called managed beans. A managed bean describes how a bean is created and managed. It has nothing to do with the bean's functionalities.
What is Backing Bean?
Backing beans are JavaBeans components associated with UI components used in a page. Backing-bean management separates the definition of UI component objects from objects that perform application-specific processing and hold data. The backing bean defines properties and handling-logics associated with the UI components used on the page. Each backing-bean property is bound to either a component instance or its value. Backing bean also defines a set of methods that perform functions for the component, such as validating the component's data, handling events that the component fires and performing processing associated with navigation when the component activates.
What are the differences between a Backing Bean and Managed Bean?
Backing Beans are merely a convention, a subtype of JSF Managed Beans which have a very particular purpose. There is nothing special in a Backing Bean that makes it different from any other managed bean apart from its usage.
MB : Managed Bean ; BB : Backing Bean
1) BB: A backing bean is any bean that is referenced by a form.
MB: A managed bean is a backing bean that has been registered with JSF (in faces-config.xml) and it automatically created (and optionally initialized) by JSF when it is needed.
The advantage of managed beans is that the JSF framework will automatically create these beans, optionally initialize them with parameters you specify in faces-config.xml.
2) BB: Backing Beans should be defined only in the request scope
MB: The managed beans that are created by JSF can be stored within the request, session, or application scopes .
Backing Beans should be defined in the request scope, exist in a one-to-one relationship with a particular page and hold all of the page specific event handling code. In a real-world scenario, several pages may need to share the same backing bean behind the scenes. A backing bean not only contains view data, but also behavior related to that data.
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