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JSTL - JSP Standard Tag Library

Last Updated : 14 Jan, 2026

JSTL (JavaServer Pages Standard Tag Library) is a collection of custom tags that encapsulate core functionalities commonly used in JSP pages. It helps reduce Java code embedded in JSPs (known as scriptlets) and promotes a cleaner MVC-based web application design.

JSTL is part of the Jakarta EE (formerly Java EE) specification and is supported in all modern servlet containers.

Why Use JSTL?

  • Eliminates the need for scriptlets (<% %>) in JSP pages
  • Improves readability and maintainability of JSP files
  • Provides built-in tags for iteration, conditional checks, and data formatting
  • Supports internationalization (i18n) and localization
  • Enables XML data processing and database interactions

JSTL Tag Libraries

LibraryPrefixDescription
Core TagscGeneral-purpose tags for variables, flow control, loops, and URL handling
Formatting TagsfmtFor number, date, and message formatting with localization support
SQL TagssqlFor executing database queries and updates (for demo/testing only)
XML TagsxFor parsing and transforming XML documents
Function TagsfnContains utility functions for string and collection operations

Adding JSTL to a Project

To use JSTL in a JSP-based web application, you need to add the JSTL library to your project and declare the required tag libraries in JSP files.

Step 1: Add JSTL Dependency

For Maven projects, add the following dependency in pom.xml:

Explanation:

  • jakarta.servlet.jsp.jstl-api provides the JSTL interfaces and tag definitions.
  • jakarta.servlet.jsp.jstl is the reference implementation required at runtime.
  • These versions are compatible with Jakarta EE 9+ and modern servlet containers such as Tomcat 10+.

Note: If you are using an older servlet container (Tomcat 9 or earlier), use the javax.servlet.jsp.jstl dependency instead.

Step 2: Declare JSTL Tag Libraries in JSP

After adding the dependency, include the required JSTL tag libraries at the top of your JSP file.

Explanation:

  • c: Core tags (conditions, loops, variable handling)
  • fmt: Formatting and internationalization
  • fn: Utility functions for strings and collections

These URIs are standard and fixed identifiers used by JSP to locate JSTL tags. They do not represent actual URLs.

Step 3: Verify JSTL Configuration (Optional Check)

Ensure that:

  • Your project is deployed on a JSP-supporting servlet container
  • JSTL JARs are available in the application’s classpath
  • JSP pages are compiled without tag-related errors
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