Im going to rephrase my questions.

QUESTIONS:

Q1) Is there something in this code thats causing the problem of not
creating the file "myobject.data" by the servlet?
Q2) What are the ways to see whether the servlet has actually received
the serialized object or not?
Q3) What path should be stored in ServletPath: the directory of the
servlet or the the name of the servlet added to that path?

COMMENTS:

C1) When executing the code, no exceptions are caught, and the servlet
doesnt create the file.
C2) As far as the notation is concerned, I reserve that for C++/VC++
(where class names start with a 'C' e.g. "CMyClass", and methd names
are capitalized e.g. "SendData()", and member variables start with "m_"
e.g. "m_nIterations". In java, I really dont care ;)

CODE:

/********************************
* Applet
*/
import java.applet.Applet;
import java.awt.Graphics;
import java.io.*;
import java.awt.*;
import javax.swing.*;
import java.net.*;

public class sender extends Applet
{
    String m_MyOutputString;
    Foo MyFoo;
    URL url = null;
    URLConnection conn = null;
    ObjectOutputStream toServlet;
    String ServletPath = "http://myjavaserver.com/~shaiian/receiver";

       public void init()
       {
       try
       {
        url=new URL(ServletPath);
        conn=url.openConnection();
           conn.setDoInput(true);
           conn.setDoOutput(true);
           conn.setUseCaches(false);
           conn.setDefaultUseCaches(false);

conn.setRequestProperty("Content-Type","application/octet-stream");
           toServlet=new ObjectOutputStream(conn.getOutputStream());
           }

           catch (IOException ioe)
           {
        JOptionPane.showMessageDialog(null,"IOException caught");
           }

           MyFoo=new Foo();
       }

       public void SendData()
       {
        try
        {
              toServlet.writeObject(MyFoo);
               }

               catch (SecurityException e)
               {
               JOptionPane.showMessageDialog(null,"Caught a security
exception\n\n" + e.getMessage());
               }

               catch (IOException ioe)
               {
          JOptionPane.showMessageDialog(null,"IOException caught");
               }
      }

      public void destroy()
      {
       try
       {
        toServlet.flush();
           toServlet.close();
       }

           catch (IOException ioe)
           {
        JOptionPane.showMessageDialog(null,"IOException caught");
           }
     }
}

/**************************
* Servlet
*/

import java.awt.*;
import java.awt.event.*;
import java.net.*;
import java.io.*;
import java.util.*;
import javax.servlet.*;
import javax.servlet.http.*;

public class receiver extends HttpServlet
{
       ObjectInputStream inputFromClient;
       Foo theData = null;

   public void doPost (HttpServletRequest req, HttpServletResponse
resp) throws ServletException, IOException
       {
               try
               {
                   inputFromClient = new
ObjectInputStream(req.getInputStream());
                   theData = (Foo) inputFromClient.readObject();
               }
               catch (ClassNotFoundException cnfE)
               {
                   cnfE.printStackTrace();
               }

//*************************************************************
               // Write to disk with FileOutputStream
               FileOutputStream fout = new
FileOutputStream("myobject.data");

               // Write object with ObjectOutputStream
               ObjectOutputStream s = new ObjectOutputStream (fout);

               // Write object out to disk
               s.writeObject ( theData );
               s.flush();
//*************************************************************
               inputFromClient.close();
   }  // end doPost
}

Let me rephrase my questions.

QUESTIONS:

Q1) After looking at the code at the end of this post, is there a
problem with it thats causing the servlet not to create the file
"myobject.dat"?
Q2) What are the possible ways to check if a servlet has received a
serialized object?
Q3) Which path should be stored in "ServletPath": the path of the
directory containing the servlet or the path of the servlet itself?

COMMENTS:

C1) The code runs with no exceptions. The only problem is that the file
"myobject.data" is not created by the servlet
C2) I thought that if an absolute path was not given for the output
file, the file will be created in the directory of the servlet, hmmm.
C3) As far as the notation of class names is concerned, class names
start with 'C' (e.g. "CMyClass"), method names, capitalized (e.g.
"SendData()"), member-variable names start with "m_" (e.g.
"m_nInterations"). Thats in C++/VC++. In Java, I really dont care ;)

Regards,
Pete

CODE:

/********************************************
* The Applet
*/

import java.applet.Applet;
import java.awt.Graphics;
import java.io.*;
import java.awt.*;
import javax.swing.*;
import java.net.*;

public class sender extends Applet
{
    Foo MyFoo;
    URL url = null;
    URLConnection conn = null;
    ObjectOutputStream toServlet;
    String ServletPath = "http://myjavaserver.com/~shaiian/receiver";

  public void init()
  {
    try
    {
        url=new URL(ServletPath);
        conn=url.openConnection();
              conn.setDoInput(true);
           conn.setDoOutput(true);
           conn.setUseCaches(false);
           conn.setDefaultUseCaches(false);
conn.setRequestProperty("Content-Type","application/octet-stream");
               toServlet=new
ObjectOutputStream(conn.getOutputStream());
    }

    catch (IOException ioe)
    {
        JOptionPane.showMessageDialog(null,"IOException caught...");
    }

    MyFoo=new Foo();
   }

  public void SendData()
  {
    try
    {
        // assuming that MyFoo member variables have been set
        toServlet.writeObject(MyFoo);

    }
    catch (SecurityException e)
    {
        JOptionPane.showMessageDialog(null,"Caught a security exception\n\n"
+ e.getMessage());
    }

    catch (IOException ioe)
    {
        JOptionPane.showMessageDialog(null,"IOException caught...");
          }
   }

  public void destroy()
  {
    try
    {
        toServlet.flush();
              toServlet.close();
    }

    catch (IOException ioe)
          {
        JOptionPane.showMessageDialog(null,"IOException caught...");
          }
  }
}

/********************************************
* The Servlet
*/

import java.awt.*;
import java.awt.event.*;
import java.net.*;
import java.io.*;
import java.util.*;
import javax.servlet.*;
import javax.servlet.http.*;

public class  receiver extends HttpServlet
{
       ObjectInputStream inputFromClient;
       Foo theData = null;

   public void init()
   {
    inputFromClient = new ObjectInputStream(req.getInputStream());
   }

   public void doPost (HttpServletRequest req, HttpServletResponse
resp) throws ServletException, IOException
   {
               try
               {
                       theData = (Foo) inputFromClient.readObject();
               }
               catch (ClassNotFoundException cnfE)
               {
                       cnfE.printStackTrace();
               }

//*************************************************************
               // Write to disk with FileOutputStream
               FileOutputStream fout = new
FileOutputStream("myobject.data");

               // Write object with ObjectOutputStream
               ObjectOutputStream s = new ObjectOutputStream (fout);

               // Write object out to disk
               s.writeObject ( theData );
               s.flush();
//*************************************************************
               inputFromClient.close();
   }  // end doPost
}

Patricia Shanahan coughed up:

If the goal is to be exposed to different things, then prolog is one of the
weirder, yet useful, ones.  It is a blurring of what-is-data and
what-is-code, since it is entirely a set of relationships.  Like an
executable BNF of sorts.  Is it data or code?

But I suspect your (Patricia's) latter (snipped) comment is the most
appropos.  (OP), go with what you are likely to need in the future.

...[rip]...