JSP | Declaration Tag (original) (raw)

Last Updated : 14 May, 2026

The Declaration Tag in JSP is used to declare variables, methods, and classes in a JSP page. The code written inside this tag is placed outside the _jspService() method by the JSP container, making it available throughout the JSP page.

Uses <%! %> syntax to declare variables, methods, and classes
Declarations become class-level members of the generated servlet
Used for defining reusable logic, not for direct output

**Syntax:

<%! declaration code %>

**Example: JSP Declaration Tag which initializes a string

HTML `

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"pageEncoding="ISO-8859-1"%>

GeeksforGeeks <%! String username="Geeks"; %>

<%="Hello : "+username %>

**Output:

Geeks

output

**Explanation:

<%! String username = "Geeks"; %> → Declares a class-level variable named username
This variable is stored outside _jspService(), so it is accessible throughout the JSP
<%= "Hello: " + username %> → Uses Expression Tag to display the value on browser

**Example : JSP Declaration Tag which initializes a method

HTML `

<%@ page language="java" contentType="text/html; charset=ISO-8859-1" pageEncoding="ISO-8859-1"%>

GeeksforGeeks <%! int factorial(int n) { if (n == 0) return 1; return n*factorial(n-1); } %> <%= "Factorial of 5 is:"+factorial(5) %>

**Output

Factorial

Output

**Explanation:

<%! int factorial(int n) { ... } %> -> Declares a method inside JSP
The method is part of the generated servlet class and can be reused
return n * factorial(n - 1) -> Uses recursion to calculate factorial
<%= factorial(5) %> -> Calls the method and prints result using Expression Tag