I have created a class that extends ServletOutputStream.  Right now it
does not do anything but my plan is to use this to capture and
manipulate data (byte[] b) sent to the output stream for my own
devices.  The class is below:

package testPkg;

import java.io.IOException;
import javax.servlet.ServletOutputStream;

public class TestOutputStream extends ServletOutputStream{
 public TestOutputStream(){
   super();
 }
 public void write(byte[] b, int off, int len) throws IOException {
   super.write(b,off,len);
 }
 public void write(int b){
 }
}

<<<<<<<<<<<<<<<<<<<<<<<

I also have a simple servlet that I am trying to call this class in:

package testPkg;

import java.io.FileInputStream;
import java.io.IOException;

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

public class OutImageTest extends HttpServlet {
 public void doGet(HttpServletRequest request, HttpServletResponse
response)
   throws ServletException, IOException {

   FileInputStream fis = new FileInputStream("C:\\test.gif");
   TestOutputStream sos =
(TestOutputStream)response.getOutputStream();
   byte [] buffer = new byte [1024];
   int len = 0;
   while ((len = fis.read(buffer))>=0) {
     sos.write(buffer, 0, len);
   }
   fis.close();
 }
}

<<<<<<<<<<<<<<<<<<<<<<<

If I replace the line above:

   TestOutputStream sos =
(TestOutputStream)response.getOutputStream();

with:

   ServletOutputStream sos = response.getOutputStream();

the servlet works no problem but with the original line I get the
error: "java.lang.ClassCastException".  Apparently it is having trouble
casting the ServletOutputStream to my class TestOutputStream even
though TestOutputStream extends ServletOutputStream although the
compiler (WebSphere, J2EE level 1.3) is requiring that I cast sos.

Anybody know what I am doing wrong?

Thanks.

Edward