How to slove follwoing error "Unreported exception java.io.IOException;"

Question

Currently I'm using following:
XP Professional
J2sdk1.4.2_01
Xerces-2_5_0
Xalan-j_2_5_1
Jakarta-tomcat-4.1.27
Jdom-b9
Current Classpath setting
User variables
PATH = c:\bmrt2.5\bin; c:\j2sdk\bin;%PATH%;%JAVA_HOME%\bin;
CLASSPATH=.;c:\xerces\xmlParserAPIs.jar;c:\xerces\xercesImpl.jar;
c:\xerces\xercesSamples.jar;c:\xalan\xercesImpl.jar;c:\xalan\xmlapis.jar;c:\xalan\xalan.jar;c:\tomcat\lib\webserver.jar;c:\tomcat\lib\jasper.jar;c:\tomcat\lib\xml.jar;c:\tomcat\common\lib\serlet.jar;c:\tomcat\lib\tools.jar; c:\tomcat\lib\tools.jar;c:\jdom\build\jdom.jar;
CATALINA_HOME= c:\tomcat
JAVA_HOME= c:\j2sdk
System variables
PATH=%SystemRoot%\system32;%SystemRoot%;%SystemRoot%\System32\Wbem;
c:\j2sdk\bin;%Path%;%JAVA_HOME%\bin;
CLASSPATH=.;c:\xerces\xmlParserAPIs.jar;c:\xerces\xercesImpl.jar;
c:\xerces\xercesSamples.jar;c:\xalan\xercesImpl.jar;c:\xalan\xmlapis.jar;c:\xalan\xalan.jar;c:\tomcat\lib\webserver.jar;c:\tomcat\lib\jasper.jar;c:\tomcat\lib\xml.jar;c:\tomcat\common\lib\serlet.jar;c:\tomcat\lib\tools.jar; c:\tomcat\lib\tools.jar;
CATALINA_HOME= c:\tomcat
JAVA_HOME= c:\j2sdk
Program
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import org.jdom.*;
import org.jdom.Element;
import org.jdom.Document;
import org.jdom.output.XMLOutputter;
import org.jdom.input.SAXBuilder;
import org.jdom.Attribute;
import java.util.List;
public class AddToList extends HttpServlet
     public Document getDocument(File sourceFile, PrintWriter errorsOut)
          try
               SAXBuilder builder = new SAXBuilder();
               Document document = builder.build(sourceFile);
               return document;
          catch(JDOMException e)
               errorsOut.print("there was a problem building the document: " e. getMessage()"<br/>"+ "Returning blank document.");
               return new Document(new Element("blank"));
     public void saveDocument(Document saveDoc, File saveFile, PrintWriter errorsOut)
          try
               FileOutputStream outStream= new FileOutputStream(saveFile);
               XMLOutputter outToFile= new XMLOutputter(" ",true);
               outToFile.output(saveDoc, outStream);
               outStream.flush();
               outStream.close();
          catch (IOException e)
               errorsOut.print("Can't save order.xml: " + e.getMessage()+"<br />");
     public void addItem(Element orderElement, String product_id, String quant)
          Element newItem =new Element("item");
          newItem.setAttribute("product_id", product_id);
          Element quantity =new Element("quantity");
          quantity.addContent(quant);
          newItem.addContent(quantity);
          orderElement.addContent(newItem);
     public void doGet(HttpServletRequest request, HttpServletResponse response)
          throws IOException, ServletException
          String thisProduct_id=request.getParameter("addProduct_id");
          String thisQuantity=request.getParameter("addQuantity");
          response.setContentType("text/html");
          PrintWriter out= response.getWriter();
          out.print("Adding "+ thisQuantity + "of item to chart "+ thisProduct_id +" ... ");
          File orderFile = new File ("file:///c:/jdk1.3/orders.xml");
          if(!orderFile.exists())
               out.print("Creating ordersrocks....<br />");
               Element root= new Element("orders");
               root.addContent(" ");
               Document document = new Document(root);
               saveDocument (document, orderFile, out);
          else
               out.print("Orders File Exists.");
          Document document =getDocument(orderFile, out);
          HttpSession session =request.getSession(true);
          String session_id= session.getId();
          Element root =document.getRootElement();
          List orders =root.getChildren();
          int num_orders =orders.size();
          boolean orderExists =false;
          int orderIndex =0;
          for(int i=0; i<num_orders; i++)
               Element iOrder=(Element)orders.get(i);
               String iOrder_id=iOrder.getAttributeValue("order_id");
               if (iOrder_id.equals(session_id))
                    orderExists=true;
                    orderIndex=i;
                    break;
          if(!orderExists)
               Element order =new Element("order");
               order.setAttribute("order_id", session_id);
               Element status =new Element("order_status");
               status.setText("open");
               order.addContent(status);
               addItem(order, thisProduct_id, thisQuantity);
               root.addContent(order);
          else
               Element thisOrder=(Element)orders.get(orderIndex);
               boolean itemExists=false;
               int itemIndex =0;
               List items =thisOrder.getChildren("item");
               int num_items =items.size();
               for(int i=0; i<num_items; i++)
                    Element iItem=(Element)items.get(i);
                    String iProduct_id =iItem.getAttribute("product_id").getValue();
                    if(iProduct_id.equals(thisProduct_id))
                         itemExists =true;
                         itemIndex =i;
                         break;
               if(itemExists)
                    Element thisItem=(Element)items.get(itemIndex);
                    String currentQuantity= thisItem.getChildText("quantity");
                    int newQuantity = Integer.parseInt(currentQuantity)+ Integer.parseInt(thisQuantity);
                    String strQuantity= new String().valueOf(newQuantity)+1;
                    thisItem.getChild("quantity").setText(strQuantity);
               else
                    addItem(thisOrder, thisProduct_id, thisQuantity);
          saveDocument (document, orderFile, out);
     public void doPost(HttpServletRequest request, HttpServletResponse response)
          throws IOException, ServletException
          doGet(request, response);
When I compile above program, it gives me following error.
Error
C:\tomcat\webapps\book\WEB-INF\classes>javac AddToList.java
AddToList.java:19: unreported exception java.io.IOException; must be caught
or declared to be thrown
Document document = builder.build(sourceFile);
^
1 error
Any help regarding this will be appreciated
Thank you
Rocks

Answer 1

Obadare
Thank for your help, my program compile successfully. But now I�m facing different kind of error on Tomcat; why it gives me following error and how do I solve it
http://localhost:8080/rock/servlet/AddToList
Following Error generate by Tomcat:
Http Status 500-
type Exception report
message
description The server encountered an internal error () that prevented it from fulfilling this request.
exception
javax.servlet.ServletException: Cannot allocate servlet instance for path /rock/servlet/AddToList
     at org.apache.catalina.servlets.InvokerServlet.serveRequest(InvokerServlet.java:435)
     at org.apache.catalina.servlets.InvokerServlet.doGet(InvokerServlet.java:180)
     at javax.servlet.http.HttpServlet.service(HttpServlet.java:740)
     at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
     at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter
(ApplicationFilterChain.java:247)
root cause
java.lang.NoClassDefFoundError: org/jdom/JDOMException
     at java.lang.Class.newInstance0(Native Method)
     at java.lang.Class.newInstance(Class.java:237)
     at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:903)
     at org.apache.catalina.core.StandardWrapper.allocate(StandardWrapper.java:668)
     at org.apache.catalina.servlets.InvokerServlet.serveRequest(InvokerServlet.java:416)
     at org.apache.catalina.servlets.InvokerServlet.doGet(InvokerServlet.java:180)
     at javax.servlet.http.HttpServlet.service(HttpServlet.java:740)
     at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
     at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter
(ApplicationFilterChain.java:247)
The following is my configuration
Classpath= .;c:\xalan\bin\xalan.jar;c:\xalan\bin\xml-apis.jar;c:\xerces\xmlParserAPIs.jar;c:\xerces\xercesImpl.jar;c:\tomcat\common\lib\servlet.jar;c:\jdom\build\jdom.jar;
Java_Home=c:\jdk1.3
Catalina_Home=c:\tomcat
Server.xml
<Engine name="Standalone" defaultHost="localhost" debug="0">
<Host name="localhost" debug="0" appBase="webapps"
unpackWARs="true" autoDeploy="true">
<Context path="/rock" docBase="rock" debug="0"
reloadable="true" crossContext="true">
P.S When I try to build javadoc it give me following error:
C:\jdom>build javadoc
JDOM Build System
Building with classpath c:\jdk1.3\lib\tools.jar;.\lib\ant.jar;.\lib\xml-apis.jar
;.\lib\xerces.jar;
Starting Ant...
Buildfile: build.xml
[javadoc] Constructing Javadoc information...
[javadoc] Building tree for all the packages and classes...
[javadoc] Building index for all the packages and classes...
[javadoc] javadoc: warning - Tag @link: Class or Package not found: javax.xml.
transform.TransformerFactory#getFeature
[javadoc] javadoc: warning - Tag @link: Class or Package not found: javax.xml.
transform.TransformerFactory#getFeature
[javadoc] Building index for all classes...
[javadoc] javadoc: warning - Tag @link: Class or Package not found: javax.xml.
transform.TransformerFactory#getFeature
[javadoc] javadoc: warning - Tag @link: Class or Package not found: javax.xml.
transform.TransformerFactory#getFeature
[javadoc] javadoc: warning - Tag @link: Class or Package not found: javax.xml.
transform.Transformer
[javadoc] javadoc: warning - Tag @link: Class or Package not found: javax.xml.
transform.Transformer
[javadoc] javadoc: warning - Tag @link: Class or Package not found: javax.xml.
transform.Transformer JAXP TrAX Transformer
[javadoc] javadoc: warning - Tag @link: Class or Package not found: javax.xml.
transform.TransformerFactory#getFeature
[javadoc] javadoc: warning - Tag @link: Class or Package not found: javax.xml.
transform.TransformerFactory#getFeature
[javadoc] javadoc: warning - Tag @link: Class or Package not found: java.lang.
Double#NaN
[javadoc] Generating C:\jdom\build\apidocs\stylesheet.css...
[javadoc] 10 warnings
BUILD SUCCESSFUL
Total time: 12 seconds