Tomcat 7 and JSTL

Question

I wrote a web application with Eclipse Tomcat and it works on my local Tomcat 7, when I tried to publish it online on a Tomcat 7, I had the following error:

Answer 1

I have been fighting with this for several hours. Here is a complete solution.

1. I am using Tomcat 7, which is a Servlet 3.0-compliant server.

2. If you desire to use the Servlet 3.0 spec, you must have your web.xml as follows:

3. If you're using Maven, your pom.xml should have these lines.

   
       javax.servlet
       javax.servlet-api
       3.0.1
       provided
   
   
   
       javax.servlet
       jstl
       1.2
   
   
   
       org.glassfish.web
       jstl-impl
       1.2
       
           
               servlet-api
               javax.servlet
           
           
               jsp-api
               javax.servlet.jsp
           
           
               jstl-api
               javax.servlet.jsp.jstl
           
       
   
   

   These dependencies are very important. JSTL 2.1 + Tomcat 7 + Servlet 3.0 is very broken unless you fix it by using these lines, especially the exclusion part. What is happening is the JSTL 2.1 Jars are actually pulling in the wrong versions of the Servlet spec--2.5. Unless you stop that from happening, you will be in a whole world of pain. A special thanks to Mr. Murray Todd Williams for these insights .

4. Finally, in case Maven can't find those JARS, you can make Eclipse happy by including three JARS with your project and doing the usual Project--> Properties--> Java Build Path and include them that way--though Maven should take care of it.

   javax.servlet-api-3.0.1.jar
   javax.servlet.jsp.jstl-1.2.1.jar
   javax.servlet.jsp.jstl-api-1.2.1.jar
   

5. Please note! This exact configuration only applies if you are using the magic combination of:

   1. A Servlet 3.0-compliant application server such as Tomcat 7

   2. Your web.xml has the right namespace for the Servlet 3.0 spec

   3. You have those three JARS and no other JSTL or Servlet JARS on your classpath.

6. Make sure you do not place copies of these JARs in your WEB-INF/lib directory because they would in that case be sent to the server thereby causing LinkageErrors.

7. In your JSP, you need to have this PRECISE line, formatted exactly as I have it or else Eclipse will whine that it doesn't recognize the c:blah tags:

   <%@taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
   

8. What a danged PITA! This is MUCH harder to implement than any other version of JSTL. This is the only example of something getting much more complicated rather than simpler in later iterations.