Servlet to download a file returning errors

Hello All,

I wrote following servlet to download a file:
__________________________________________
package controller;

import javax.servlet.*;
import java.io.*;
import javax.servlet.http.*;
import java.util.*;

class DownloadServ extends HttpServlet{

public void doGet(HttpServletRequest request, HttpServletResponse
response) throws ServletException, IOException{

 response.setContentType("application/pdf");

  ServletContext ctx=getServletContext();
  InputStream is=ctx.getResourceAsStream("/
21stCenturyTiger_Christmas_wishes_2009.pdf");

 int read=0;
 byte[ ] bytes=new byte[1024];

 OutputStream os=response.getOutputStream();

 while((read=is.read(bytes)) != -1){
   os.write(bytes,0,read);
 }

 os.flush();
 os.close();
}
}
_________________________________________________________

But it is showing the following error in browser:

________________________________________________________
exception

javax.servlet.ServletException: Error instantiating servlet class
com.example.web.DownloadServ

org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:
104)

org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:
261)

org.apache.coyote.http11.Http11AprProcessor.process(Http11AprProcessor.java:
852)
    org.apache.coyote.http11.Http11AprProtocol
$Http11ConnectionHandler.process(Http11AprProtocol.java:584)
    org.apache.tomcat.util.net.AprEndpoint$Worker.run(AprEndpoint.java:
1508)
    java.lang.Thread.run(Unknown Source)
________________________________________________________

Please help me with correcting the code.

Thanks in Advance.

Regards
Kuber