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Editorial Team
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Asked: 2026-05-20T04:56:18+00:00

As the title says, my JSTL tags don’t work on my development server, but

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As the title says, my JSTL tags don’t work on my development server, but do work on Google’s actual server.

I simplified the code to the bare bone to make sure there wasn’t anything wrong with the code, so here’s what I’ve got.

JSP

<%@ page language="java" contentType="text/html; charset=ISO-8859-1" pageEncoding="ISO-8859-1" isELIgnored="false"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Page Title</title>
</head>
<body>
    <c:choose>
        <c:when test="${2+2==4}">sum works</c:when>
        <c:otherwise>sum doesn't work</c:otherwise>
    </c:choose>
</body>

My configuration is as follows (which I think is correct and which works on Google’s server):
I’m using

  • Eclipse IDE
  • Servlet 2.5
  • No jstl jar added to WEB-INF\lib
  • No tld added anywhere
  • No taglib reference

on web.xml

However, I have also tried a number of combinations of the following and none of them worked:

  • jstl-1.2.jar added to the build path
  • c.tld added to WEB-INF
  • taglib reference added to web.xml

Error is below: 

HTTP ERROR 500
Problem accessing /index.html. Reason: 

    javax/servlet/jsp/tagext/TagSupport

Caused by:

java.lang.NoClassDefFoundError: javax/servlet/jsp/tagext/TagSupport
    at java.lang.ClassLoader.findBootstrapClass(Native Method)
    at java.lang.ClassLoader.findBootstrapClassOrNull(ClassLoader.java:927)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:298)
    at com.google.appengine.tools.development.DevAppServerClassLoader.loadClass(DevAppServerClassLoader.java:87)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:248)
    at java.lang.ClassLoader.defineClass1(Native Method)
    at java.lang.ClassLoader.defineClassCond(ClassLoader.java:632)
    at java.lang.ClassLoader.defineClass(ClassLoader.java:616)
    at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:141)
    at java.net.URLClassLoader.defineClass(URLClassLoader.java:283)
    at java.net.URLClassLoader.access$000(URLClassLoader.java:58)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:197)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
    at com.google.appengine.tools.development.DevAppServerClassLoader.loadClass(DevAppServerClassLoader.java:87)
         ...

Strangely, though, <c:out value="${blah}"/> works both on the development and remote servers. other core tags don’t work. If I try to add fmt tags, they don’t work as well.

Any ideas?

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1 Answer

  1. Editorial Team

    The fact that google searches were returning no useful information already indicated that this problem was unique to my configuration.

    Alas, I finally managed to figure out what was wrong and I’m just posting the solution in case someone comes across this problem, which dreaded me for days.

    Turned out I had added Tomcat’s servlet-api.jar and jstl jar into Eclipse’s default JRE library to avoid having to add them each time into WEB-INF\lib (i.e. Window > Preferences > Java > Installed JREs > Edit > Add External Jar).

    Once I started developing in GAE, this configuration started causing a conflict with AppEngine’s own servlet-api.jar and jstl jars.

    The answer was simply to remove the Tomcat jars from the JRE library.

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