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Asked: 2026-06-03T23:42:37+00:00

I am just learning JSP and am testing using JSTL on Tomcat 7. I

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I am just learning JSP and am testing using JSTL on Tomcat 7. I am able to successfully define and use custom tags. But when I attempt to implement JSTL the container throws two exceptions. How can I fix this so the jsp will translate properly?

java.lang.ClassNotFoundException: javax.servlet.jsp.tagext.TagLibraryValidator
java.lang.NoClassDefFoundError: javax/servlet/jsp/tagext/TagLibraryValidator

I’m using the following jar files.

javax.servlet.jsp.jstl-1.2.1.jar
javax.servlet.jsp.jstl-api-1.2.1.jar

I have placed the two JSTL 1.2.1 jars in WEB-INF/lib of the test web app and the CLASSPATH for my JRE. I have also marked the two jars for export in the build path options in Eclipse.

index.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <title>Insert title here</title>
    </head>
    <body>
        <c:out value="JSTL works."></c:out>
    </body>
</html>
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1 Answer

  1. Editorial Team

    java.lang.NoClassDefFoundError: javax/servlet/jsp/tagext/TagLibraryValidator

    This class is part of JSP 2.0. Tomcat is a Servlet 3.0 / JSP 2.2 container. Make sure that your web.xml is declared conform Servlet 3.0.

    <?xml version="1.0" encoding="UTF-8"?>
<web-app 
    xmlns="http://java.sun.com/xml/ns/javaee"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
    version="3.0">

    <!-- Config here. -->

</web-app>

    And also that you don’t have arbitrary JAR files of a different container make/version like jsp-api.jar from Tomcat 5.5 or so in your /WEB-INF/lib. It would otherwise only conflict. See also How do I import the javax.servlet API in my Eclipse project?

    I have placed the two JSTL 1.2.1 jars in WEB-INF/lib of the test web app

    That should be sufficient. If cleaning the web.xml and the classpath still doesn’t fix the problem, perhaps you don’t have the right JARs at all. In our JSTL wiki page you can find a download link to a single jstl-1.2.jar file. Drop it in /WEB-INF/lib and remove the other JARs.

    and the CLASSPATH for my JRE.

    Please don’t do that. Just dropping the JSTL JAR in /WEB-INF/lib is sufficient. Also make sure that you don’t drop arbitrary servletcontainer-specific JARs in your JRE/lib or JRE/lib/ext. Just don’t touch those folders. Webapp-specific libraries should go in /WEB-INF/lib. If you’re using an IDE, it will then do automatically all the necessary magic. You don’t even need to fiddle in buildpath properties. The CLASSPATH environment variable is only used when you run java command in your command console and even then only when you run it without the -cp, -classpath and -jar arguments.

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