J2EE: Directing process output to the client

I'm writing a servlet that runs an external program, captures the HTML
that it writes out, and sends that to the client. So I'm doing this:

           Runtime rt = Runtime.getRuntime();
           Process pr = rt.exec(cmdline, env, new File(cgiDir));

I can send data to the process's STDIN, and retrieve its STDERR and
write it to a file, so I know it's running, and I KNOW that it's
written something to STDOUT. Here's how I'm trying to process that:

           ServletOutputStream os = response.getOutputStream();
           new OutputPollster(pr.getInputStream(), os).start();
 

Where OutputPollster is:

class OutputPollster extends java.lang.Thread
   {
      private java.io.InputStream m_is;
      private ServletOutputStream sosOut;
   
      OutputPollster(java.io.InputStream is, ServletOutputStream
sosOut)
      {
          m_is = is;
          this.sosOut = sosOut;
      }

      public void run()
      {
         int len;
         byte buf[] = new byte[128];
         try
         {
            while (-1 != (len = m_is.read(buf)))
            {
               String chunk = new String(buf, 0, len);
               sosOut.print(chunk);
            }

                sosOut.flush();
         }
         catch (java.io.IOException ex)
         {
             //deal with the exception
             System.out.println("Error: " + ex.getMessage());
         }
      }

But absolutely NOTHING gets sent to the client browser! What's wrong
with this?

--
Tim Slattery
Slattery_T@bls.gov
http://members.cox.net/slatteryt