In JSP, variable scopes define where and how long a variable (object) is available during the lifecycle of a web application.

There are four variable scopes in JSP:

Scope	Object Availability	Lifetime
page	Available only in the current page	Until the page finishes processing
request	Available for the current HTTP request	Until the request is completed (forwarded or responded)
session	Available for the current user session	Until the session times out or is invalidated
application	Available for all users, all sessions	Until the server shuts down or app is undeployed

🔵 1. page Scope

• Visible only in the current JSP page.
• Not shared across requests or other pages.

Example:

<jsp:useBean id="user" class="com.example.User" scope="page" />

user exists only while this JSP page is executing.

After the response is sent, it disappears.

🔵 2. request Scope

• Shared across the entire request, including forwards and includes.
• Used to pass data between servlets, filters, and JSPs.

Example:

<jsp:useBean id="user" class="com.example.User" scope="request" />

If you forward the request to another page, it can still access user.

🔵 3. session Scope

• Persists across multiple requests from the same user/browser session.
• Good for storing user login data, shopping carts, etc.

Example:

<jsp:useBean id="user" class="com.example.User" scope="session" />

user stays available until the session expires (usually after inactivity).

🔵 4. application Scope

• Global scope — available to all users and sessions within the web application.
• Useful for application-wide settings, counters, shared resources.

Example:

<jsp:useBean id="config" class="com.example.Config" scope="application" />

config is visible everywhere in the app until the server restarts or app is undeployed.

📚 Summary Table

Scope	Object tied to	Accessed from	Lifetime
page	Current JSP page	Only the current page	Until page response completes
request	HTTP Request object	Forwarded/Included pages too	Until request completes
session	User’s Session object	All pages in session	Until session timeout
application	Application Context	All pages and all users	Until server shutdown

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📢 How They Relate to Java Objects

In Java code inside JSPs, you access them using:

• pageContext → for page scope
• request → for request scope
• session → for session scope
• application → for application scope

Example in JSP:

<%= session.getAttribute("user") %>
<%= request.getAttribute("orderId") %>
<%= application.getAttribute("config") %>

🎯 Final Key Points:

• Use page for local temporary data.
• Use request for passing data between pages.
• Use session for user-specific long-term data.
• Use application for global shared data.