java.lang.NoClassDefFoundError: com/hp/hpl/jena/shared/BadURIException on running servlet

Question

I get a "java.lang.NoClassDefFoundError: com/hp/hpl/jena/shared/BadURIException" when running a very simple servlet. The error points back to the initialisation of the "Tagger" class. The code is as follows

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import my.package.Tagger;

public class NormaliserServlet extends HttpServlet{
    public void doGet(HttpServletRequest req, HttpServletResponse response) throws IOException{
     Tagger pot = new Tagger("");

     response.setContentType("text");
     PrintWriter out = response.getWriter();
     out.println("hello");
        out.println(pot.someMethod());
     out.close();

     this.log("Request for normaliser");
    }
}

The war file contains the jar file defining "Tagger" in WEB-INF/lib and a similar invocation works outside of a servlet. I can't seem to find what the problem would be. The web.xml is pretty standard too:

<servlet>
    <servlet-name>normalise</servlet-name>
    <servlet-class>NormaliserServlet</servlet-class>
</servlet>
<servlet-mapping>
    <servlet-name>normalise</servlet-name>
    <url-pattern>/normalise</url-pattern>
</servlet-mapping>

I'm using winstone as the servlet container, but i get the exact same error in tomcat. The stacktrace is:

java.lang.NoClassDefFoundError: com/hp/hpl/jena/shared/BadURIException
    at NormaliserServlet.doGet(NormaliserServlet.java:13)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:104)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:45)
    at winstone.ServletConfiguration.execute(ServletConfiguration.java:249)
    at winstone.RequestDispatcher.forward(RequestDispatcher.java:335)
    at winstone.RequestHandlerThread.processRequest(RequestHandlerThread.java:244)
    at winstone.RequestHandlerThread.run(RequestHandlerThread.java:150)
    at java.lang.Thread.run(Thread.java:619)

Answer 1

It looks like you're missing the jar for Jena(?) which defines the BadURIException class. Is that jar included in your WEB-INF/lib directory as well? Have you tried looking at the unpacked war file in Winstone and checking if the relevant jars are all there?

Answer 2

You are missing the jar files from the Jena project. They should be in your WAR file.

It could be an indirect dependency of some other library that you use. Take a look at the stacktrace to see what else sits between Jena and your code.

Answer 3

This class com/hp/hpl/jena/shared/BadURIException, presumably instantiated by Tagger is not in your servlet container's classpath.

If it works outside your servlet container, it's likely you have entries in your environment defining the classpath. Check the classpath and copy the missing lib within the servlet container's lib directory.