Servlet + Tomcat NoClassDefFoundError

Question

Hi,
I am developing a servlet which takes data from Amazon's Web services (in XML format) and then outputs a RSS feed. I use xerces for parsing the XML and then use Rome to output the RSS feed. When I run the servlet then I get the following error.
However when I run the same code over the commandline, it runs fine, however running it as a servlet, it shows the NoClassDefFoundError . I am also sending the code , it contains the commented out System.out statements which I use when I am running it over the command line
Thanks
Gaurav
javax.servlet.ServletException: Invoker service() exception
     at org.apache.catalina.servlets.InvokerServlet.serveRequest(InvokerServlet.java:524)
     at org.apache.catalina.servlets.InvokerServlet.doPost(InvokerServlet.java:216)
     at javax.servlet.http.HttpServlet.service(HttpServlet.java:760)
     at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
     at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:247)
     at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:193)
     at filters.ExampleFilter.doFilter(ExampleFilter.java:149)
     at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:213)
     at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:193)
     at filters.ExampleFilter.doFilter(ExampleFilter.java:149)
     at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:213)
     at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:193)
     at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:256)
     at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643)
     at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)
     at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
     at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
     at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643)
     at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:494)
     at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:641)
     at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)
     at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
     at org.apache.catalina.core.StandardContext.invoke(StandardContext.java:2416)
     at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:180)
     at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643)
     at org.apache.catalina.valves.ErrorDispatcherValve.invoke(ErrorDispatcherValve.java:171)
     at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:641)
     at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:172)
     at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:641)
     at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)
     at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
     at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:174)
     at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643)
     at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)
     at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
     at org.apache.coyote.tomcat4.CoyoteAdapter.service(CoyoteAdapter.java:223)
     at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:601)
     at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection(Http11Protocol.java:392)
     at org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java:565)
     at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:619)
     at java.lang.Thread.run(Thread.java:536)
root cause
java.lang.NoClassDefFoundError
     at form_input.doPost(form_input.java:84)
     at javax.servlet.http.HttpServlet.service(HttpServlet.java:760)
     at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
     at org.apache.catalina.servlets.InvokerServlet.serveRequest(InvokerServlet.java:466)
     at org.apache.catalina.servlets.InvokerServlet.doPost(InvokerServlet.java:216)
     at javax.servlet.http.HttpServlet.service(HttpServlet.java:760)
     at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
     at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:247)
     at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:193)
     at filters.ExampleFilter.doFilter(ExampleFilter.java:149)
     at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:213)
     at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:193)
     at filters.ExampleFilter.doFilter(ExampleFilter.java:149)
     at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:213)
     at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:193)
     at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:256)
     at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643)
     at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)
     at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
     at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
     at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643)
     at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:494)
     at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:641)
     at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)
     at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
     at org.apache.catalina.core.StandardContext.invoke(StandardContext.java:2416)
     at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:180)
     at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643)
     at org.apache.catalina.valves.ErrorDispatcherValve.invoke(ErrorDispatcherValve.java:171)
     at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:641)
     at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:172)
     at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:641)
     at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)
     at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
     at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:174)
     at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643)
     at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)
     at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
     at org.apache.coyote.tomcat4.CoyoteAdapter.service(CoyoteAdapter.java:223)
     at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:601)
     at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection(Http11Protocol.java:392)
     at org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java:565)
     at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:619)
     at java.lang.Thread.run(Thread.java:536)
The Code:
//JAXP 1.1
import org.w3c.dom.*;
import org.w3c.dom.Document;
import javax.xml.parsers.*;
import org.apache.xerces.dom.DocumentImpl;
import org.apache.xerces.dom.DOMImplementationImpl;
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import java.net.*;
import java.util.Vector;
import org.apache.xerces.jaxp.*;
import org.apache.xerces.*;
import org.apache.xerces.dom.*;
import org.apache.xerces.parsers.*;
//import org.apache.xml.serialize.*;
import org.xml.sax.*;
import com.sun.syndication.feed.synd.*;
import com.sun.syndication.io.SyndFeedOutput;
import com.sun.syndication.io.FeedException;
import java.io.IOException;
import java.text.ParseException;
import java.io.FileWriter;
import java.io.Writer;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.List;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class form_input extends HttpServlet
private static final DateFormat DATE_PARSER = new SimpleDateFormat("yyyy-MM-dd");
     public void doGet(HttpServletRequest request, HttpServletResponse response)
                         throws IOException, ServletException
          doPost(request,response);
     public void doPost(HttpServletRequest request, HttpServletResponse response)
                         throws IOException, ServletException
response.setContentType("text/xml");
          PrintWriter out = response.getWriter();
          URL data = new URL("http://xml.amazon.com/onca/xml3?t=myWebsite-20&dev-t=1RX5WFR818MJJAEN8A02&KeywordSearch=dogs&mode=books&type=lite&page=1&f=xml");
          URLConnection connection = data.openConnection();
          connection.setUseCaches(false);
Document doc= null;
          NodeList DetailList = null;
          NodeList DetailChildren = null;
          Node Detail = null;
          Node DetailChild = null;
          Node ChildValue = null;
          DOMParser dparsers = new DOMParser();
          List entries = new ArrayList();
          SyndFeed feed = new SyndFeedImpl();
          SyndEntry entry;
          SyndContent description;
          SyndFeedOutput output = new SyndFeedOutput();
          try
               feed.setFeedType("rss_1.0");
               feed.setTitle("Amazon search for dog");
feed.setLink("http://www.amazon.com");
feed.setDescription("Amazon search results for dogs");
               dparsers.parse(new InputSource(connection.getInputStream()));
               doc = dparsers.getDocument();
               DetailList = doc.getElementsByTagName("Details");
               for( int i=0; i<DetailList.getLength(); i++)
                    Detail = DetailList.item(i);
                    DetailChildren = Detail.getChildNodes();
                    entry = new SyndEntryImpl();
                    for( int j=0; j<DetailChildren.getLength(); j++)
                         //Iterate through each of the children and start filling out the RSS thingie
                         //Gotta extract Asin, ProductName, ReleaseDate, Manufacturer, Authors -> Author
                         DetailChild = DetailChildren.item(j);
                         if(DetailChild.getNodeName().equals("Asin"))
                              //if(DetailChild.hasChildNodes())
                              //     System.out.println(DetailChild.getNodeName() + " has child nodes");
                              ChildValue = DetailChild.getFirstChild();
                              //System.out.println(DetailChild.getNodeName()+ " type = "+DetailChild.getNodeType()+" value="+ChildValue.getNodeValue());
                              entry.setLink("http://www.amazon.com/exec/obidos/ASIN/"+ChildValue.getNodeValue());
                              //System.out.println("Match found for Asin");
                         else if(DetailChild.getNodeName().equals("ProductName"))
                              ChildValue = DetailChild.getFirstChild();
                              //System.out.println(DetailChild.getNodeName()+ " type = "+DetailChild.getNodeType()+" value="+ChildValue.getNodeValue().length());
                              if(ChildValue.getNodeValue().length() > 100 )
                                   entry.setTitle(ChildValue.getNodeValue().substring(0,100));
                              else
                                   entry.setTitle(ChildValue.getNodeValue());
                              //System.out.println("Match found for ProductName");
                         else if(DetailChild.getNodeName().equals("ReleaseDate"))
                              ChildValue = DetailChild.getFirstChild();
                              //System.out.println(DetailChild.getNodeName()+ " type = "+DetailChild.getNodeType()+" value="+ChildValue.getNodeValue());
                              //System.out.println("ReleaseDate: "+DetailChild.getNodeValue());
                              //entry.setPublishedDate(DATE_PARSER.parse(DetailChild.getNodeValue()));
                              entry.setPublishedDate(DATE_PARSER.parse("2004-07-07"));
                              //System.out.println("Match found for ReleaseDate");
                         else if(DetailChild.getNodeName().equals("Manufacturer"))
                              ChildValue = DetailChild.getFirstChild();
                              //System.out.println(DetailChild.getNodeName()+ " type = "+DetailChild.getNodeType()+" value="+ChildValue.getNodeValue());
                              description = new SyndContentImpl();
                              description.setType("text/plain");
                              description.setValue("Initial release of Rome");
                              entry.setDescription(description);
                    entries.add(entry);
               feed.setEntries(entries);
               String fxml = output.outputString(feed);
               out.println(fxml);
          catch (ParseException ex) {
// IT CANNOT HAPPEN WITH THIS SAMPLE
ex.printStackTrace();
out.println("ERROR: "+ex.getMessage());
          catch( SAXException se)
               se.printStackTrace();
out.println("ERROR: "+se.getMessage());
          catch (Exception ex) {
ex.printStackTrace();
out.println("ERROR: "+ex.getMessage());

Answer 1

Hi,
I am building the servlet for now in
$TOMCAT_HOME/webapps/examples/WEB-INF/classes ,
however there is no 'lib' directory in
$TOMCAT_HOME/webapps/examples/WEB-INF . I created one
and put the jar files there, but still I get the same
error. Infact when I start the server, I do not see
the jar file in CLASSPATH
Thanks
GauravYou shouldn't be putting your app in the examples directory.
You should create a directory under TOMCAT_HOME/webapps for YOUR individual apps. Each one should have a WEB-INF directory under that, and /classes and /lib under that. Your web.xml belongs in the WEB-INF directory. Your .class files, and their package directories, belong under WEB-INF/classes. 3rd party JARs, like JDBC drivers, belong in WEB-INF/lib.
The problem is that you don't know how to deploy a Web app properly on Tomcat.