Backing Bean vs Managed Bean

In JavaServer Faces (JSF) development, both Managed Beans and Backing Beans play essential roles, but they serve different purposes and have distinct characteristics:

1.  Managed Bean:

• Purpose:  Managed beans are Java objects managed by the JSF framework, primarily used to encapsulate the application data and business logic that is associated with JSF pages.
• Scope:  Managed beans can have different scopes (@RequestScoped, @SessionScoped, @ApplicationScoped, @ViewScoped, etc.), defining the lifecycle and visibility of the bean’s data across JSF pages.
• Example:  Below is an example of a Managed Bean in JSF:

     java
     import javax.faces.bean.ManagedBean;
     import javax.faces.bean.RequestScoped;

     @ManagedBean
     @RequestScoped
     public class UserBean {
         private String username;
         private String password;

         // Getters and setters for username and password

         public String login() {
             // Logic to authenticate user
             return "welcome"; // Navigation outcome
         }
     }

In this example, UserBean is a Managed Bean with @RequestScoped scope, encapsulating user credentials and a method login to authenticate users.

2.  Backing Bean:

• Purpose:  Backing beans are a specific type of managed beans that act as a bridge between JSF pages and the application’s business logic or data model.
• Scope:  Backing beans typically have a scope that matches the lifespan of the corresponding JSF page (@RequestScoped, @ViewScoped, etc.).
• Example:  Below is an example of a Backing Bean in JSF:

     java
     import javax.faces.bean.ManagedBean;
     import javax.faces.bean.ViewScoped;

     @ManagedBean
     @ViewScoped
     public class UserBackingBean {
         private String username;
         private String password;

         // Getters and setters for username and password

         public String login() {
             // Logic to authenticate user
             return "welcome"; // Navigation outcome
         }
     }

In this example, UserBackingBean is a Backing Bean with @ViewScoped scope, encapsulating user credentials and a method login to authenticate users.

Differences between Managed Bean and Backing Bean:

• Purpose:  
  • Managed Bean:  Generally encapsulates application data and business logic, can be used across multiple JSF pages.
  • Backing Bean:  Specifically tailored to support a single JSF page, serving as a mediator between UI components and application logic.
• Scope:  
  • Managed Bean:  Can have various scopes (@RequestScoped, @SessionScoped, etc.) depending on the lifecycle requirements.
  • Backing Bean:  Typically scoped to the lifespan of the associated JSF page (@RequestScoped, @ViewScoped, etc.), ensuring data persistence and management within that page’s context.
• Usage:  
  • Managed Bean:  Used more broadly across the application to manage application-wide data and logic.
  • Backing Bean:  Used specifically to handle interactions and data binding for a particular JSF page.