Parsing xml with dom4j - cannot find jar file

Question

Hi,
I'm using Jdeveloper 10g and tomcat 5.5.9. I have a servlet which calls a java class (ParseXML.java) that trys to parse an xml string using dom4j. A snippet of ParseXML.java...
import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.io.SAXReader;
public class ParseXML  {
public ParseXML(String xml) {
          this.XML_STRING = xml;
     public String parse() {
          SAXReader reader = new SAXReader();
          Document document = null;
          try  {
               document = reader.read(XML_STRING);
               } catch (DocumentException de)  {
               return de.getMessage();
          } catch (Exception e) {
               return e.getMessage();
               return "The xml root value is: " + document.getRootElement().getName();
} I've downloaded the dom4j 1.6.1 jar and put it on the project class path (specified in the jdev project proerties), and my code also compiles ok. But when i try to instantiate ParseXML from my servlet i get a runtime exception:
javax.servlet.ServletException: Servlet execution threw an exception
root cause
java.lang.NoClassDefFoundError: org/dom4j/DocumentException
     arcims.GetMapServlet.doPost(GetMap.java:45)
     javax.servlet.http.HttpServlet.service(HttpServlet.java:709)
     javax.servlet.http.HttpServlet.service(HttpServlet.java:802I'm not sure if this is a class path issue or something else; i've checked and rechecked the classpath and nothing seems amiss.
Suggestions, anyone?

Answer 1

Question: Is it really necessary to use a
StringReader if my xml document is not saved to disk?
I get XML_STRING from a web service, convert it into
a xml document so i can manipulate/parse it, but then
i don't save the document, i just discard it. How
does my system's default character set affect string
manipulations that i do within my java app?Your system's default charset doesn't have anything to do with string manipulations, if by that you mean substrings and concatenations of strings. It is used when you convert strings to bytes and bytes to strings. If your string contains a character that can't be handled by your default charset, then converting that string to bytes will put ? in place of that character. Converting those bytes back to a string will leave the ? as is. Thus your string has been changed.
Also converting the string to bytes can have bad results, because the first thing the XML parser does is to convert the bytes back to a string, using the charset declared in the XML. If this charset is different from your system's default, then your XML may be corrupted by this process if it contains characters that are encoded differently in the two charsets. The typical example of this is European accented letters like �, which are encoded differently in ISO-8859-1 or Windows-1252 (most people's default charsets) and UTF-8 (the default XML charset).
Besides, converting the string to bytes just so it can be immediately converted back to a string is rather wasteful.