WhiteboardApplet.java
--------------------------------

import java.awt.*;
import java.applet.*;
import java.awt.event.*;
import java.util.*;

import java.net.*;
import java.io.*;

public class WhiteBoardApplet extends Applet
  implements ActionListener, AdjustmentListener,KeyListener,
MouseListener,
            MouseMotionListener, WindowListener
{

       Socket skt;
       ObjectOutputStream oos;
       Vector ht;

       ServerSocket ss2;
       Socket cs2;
       Vector ht2;
       ObjectInputStream ois2;

       //declare variables
       Image offscreenImage;
       Graphics offscreenImageG;
       Graphics drawPanelG;
       int offscreeImage_width, offscreeImage_height;
       boolean isButtonPressed;
       int pre_x, pre_y; //the coordinates at the beginning of mouse
dragged
       int x, y; //the coordinates in the end of mouse dragged
       int top_left_corner_x, top_left_corner_y; //the x and y
coordonate of top-left corner
                                         //that a image is drawn with
in the graphic context
       int scrollbarV_value; //to hold vertical scrollbar value
       int scrollbarH_value; //to hold herizonal scroll bar value
       String s; //to hold string input from keyboard
       /***************************
        * init()
        * description: The entry point for the applet.
        * build window and initiate variables
        * **************************
       */
       public void init()
       {           //build window
          buildWindow ( );
          //initiate variables
          isButtonPressed=false;
          top_left_corner_x=0;
          top_left_corner_y=0;
          offscreeImage_width=2000;
          offscreeImage_height=2000;

          drawPanelG = drawPanel.getGraphics ();

          offscreenImage = this.createImage( offscreeImage_width,
offscreeImage_height);
          offscreenImageG = offscreenImage.getGraphics();
          offscreenImageG.setColor( Color.white );
          offscreenImageG.fillRect( 0, 0, offscreeImage_width,
offscreeImage_height);
          offscreenImageG.setColor( Color.black );

          ht = new Vector();
          ht2 = new Vector();

          GandhiUpdate2();
       }

       /***************************
       * update()
       * description:
       * update the container, call the method paint()
       * **************************
       */
       public void update( Graphics g ) {
           paint( g );
       }

      /***************************
       * paint()
       * description:
       * drawPanelG draw offscreenImage,
       * begin from the top left corner
       * **************************
       */

       public void paint( Graphics g ) {
          drawPanelG.drawImage ( offscreenImage,top_left_corner_x,
top_left_corner_y, this );
       }

       /**************Build Window****************/

       //declare variables for buiding window
       Frame outerBox; //to place all visible components
       Panel topPanel; //to hold "clear" button
       Panel drawPanel; // draw area
       Panel bottomPanel; // to hold herizonal scrollbar and message
area
       Scrollbar scrollbarV; //vertical scrollbar
       Scrollbar scrollbarH; //herizonal scrollbar
       TextField message;
       Button clearButton;

       private void buildWindow ( ) {

       // *** Instantiate objects
       outerBox = new Frame ( );
       topPanel= new Panel();
       drawPanel = new Panel ( );
       bottomPanel = new Panel ( );

       //***build button
       Button clearButton=new Button("Clear");
       clearButton.setBackground(new Color(193, 211, 245));
       clearButton.addActionListener(this);

       // *** build the scrollbars and add addAdjustmentListener
       scrollbarV = new Scrollbar (Scrollbar.VERTICAL, 0, 100, 0,
1000 );
       scrollbarV.addAdjustmentListener ( this );
       scrollbarH = new Scrollbar (Scrollbar.HORIZONTAL, 0, 100, 0,
1000 );
       scrollbarH.addAdjustmentListener ( this );
            // *** build the message display area
       message = new TextField ( "Messages Displayed Here", 80 );
       message.setEditable ( false ); //set the textField message as
not editable

      //build the top panel
       topPanel.setSize(600, 30);
       topPanel.add(clearButton);

      //register envent on the draw panel(draw area)
       drawPanel.addKeyListener(this);
       drawPanel.addMouseListener(this);
       drawPanel.addMouseMotionListener(this);

       // *** build the bottom panel
       bottomPanel.setLayout ( new BorderLayout ( ) );
       bottomPanel.add ( "North", scrollbarH );
       bottomPanel.add ( "South", message );

       // *** Set colors
       topPanel.setBackground(Color.gray);
       drawPanel.setBackground (Color.white);

       // *** build the window
       outerBox.setLayout (new BorderLayout ( ) );
       outerBox.add ("North", topPanel);
       outerBox.add ("Center", drawPanel);
       outerBox.add ("South", bottomPanel);
       outerBox.add ("East", scrollbarV);
       outerBox.setSize (600, 500);
       outerBox.setBackground (Color.white);
       outerBox.addWindowListener (this);
       outerBox.setVisible ( true );
     } // end buildWindow ()

       //*********** Interface Methods ***********

       //**** actionPerformed methods
       public void actionPerformed ( ActionEvent e ) {
         //call actionClear()
         actionClear();
       }//end actionPerformed method

       //actionClear method
       private void actionClear(){
          //fill the offscreenImage all white
          offscreenImageG.setColor( Color.white );
          offscreenImageG.fillRect( 0, 0, offscreeImage_width,
offscreeImage_height);
          offscreenImageG.setColor( Color.black );
          repaint();
       }//end actionClear

       //**** AdjustmentListener method
       public void adjustmentValueChanged ( AdjustmentEvent e ) {
          Object s = e.getSource();
          // *** process Scrollbar actions
          if ( s instanceof Scrollbar ) {
              if ( s == scrollbarV ) {
                 scrollbarV_value=scrollbarV.getValue();
                 top_left_corner_y = - scrollbarV_value;
                 message.setText ( "Vertical ScrollBar value: " +
scrollbarV_value );
                 repaint();
              }

              if ( s == scrollbarH ) {
                 scrollbarH_value=scrollbarH.getValue();
                 top_left_corner_x = - scrollbarH_value;
                 message.setText ( "Horlzontal ScrollBar value: " +
scrollbarH_value);
                 repaint();               }
          } // end process scrollbar actions
       } //end adjustmentValueChanged method

       //*****KeyListener methods
       public void keyTyped( KeyEvent e ) {
           char c = e.getKeyChar();
           if ( c != KeyEvent.CHAR_UNDEFINED ) {
              s = s + c;
              offscreenImageG.drawString( s, x+scrollbarH_value, y
+scrollbarV_value);
              repaint();
              e.consume();
           }            message.setText("Typing...");
       }

       public void keyPressed(KeyEvent e){}

       public void keyReleased(KeyEvent e){}

       //****MouseListener methods

       public void mouseClicked(MouseEvent e){
         // called after a press and release of a mouse button
         // with no motion in between
         // (If the user presses, drags, and then releases, there
will be
         // no click event generated.)
         x = e.getX();
         y = e.getY();
         s = "";
         offscreenImageG.drawString( s, x+scrollbarH_value, y
+scrollbarV_value);
         repaint();
         e.consume();
         message.setText("Mouse clicked");
       } //end mouseClicked

       public void mousePressed(MouseEvent e){
         //called after a mouse button is pressesd;
         isButtonPressed=true;
         message.setText("Mouse Pressed.");
       }

       public void mouseReleased(MouseEvent e)
       {
         isButtonPressed=false;

         try
         {
           skt = new Socket("localhost", 9000);
           oos = new ObjectOutputStream(skt.getOutputStream());
           oos.writeObject(ht);
           oos.close();
           ht.clear();
         }
         catch (Exception x)
         {
            x.printStackTrace();
         }

         message.setText("Mouse released.");
       }

       public void mouseEntered(MouseEvent e){
       }

       public void mouseExited(MouseEvent e){
         }

       //*****MouseMotionListener methods

       public void mouseDragged(MouseEvent e){
          if(isButtonPressed==true)
          {
            pre_x=e.getX()+scrollbarH_value;
            pre_y=e.getY()+scrollbarV_value;
            isButtonPressed=false;
          }
          x=e.getX()+scrollbarH_value;
          y=e.getY()+scrollbarV_value;
          offscreenImageG.drawLine(pre_x, pre_y, x, y);
          drawLines(pre_x + ":" + pre_y + ":" + x + ":" + y);
          pre_x=x;
          pre_y=y;
          repaint();
          e.consume();
          message.setText(pre_x + ":" + pre_y + ":" + x + ":" + y);
       } //end  mouseDragged

       public void drawLines(String m)
       {
          ht.add(m);
       }

       public void GandhiUpdate2()
       {
           try
           {
               ss2 = new ServerSocket(8000);
               cs2 = ss2.accept();

               while(true)
               {
                   ois2 = new ObjectInputStream(cs2.getInputStream());
                   ht2 = (Vector)ois2.readObject();
                   //System.out.println(ht2);
                   ois2.close();
                   cs2.close();
                   cs2= ss2.accept();
                   repaint();
               }
           }
           catch (Exception e)
           {
               e.printStackTrace();
           }
       }

       public void mouseMoved(MouseEvent e) {
           message.setText("x: "+e.getX()+", y: "+e.getY());
       }

       //**** WindowListener methods
       public void windowActivated ( WindowEvent e ) {
         }
       public void windowDeactivated ( WindowEvent e ) {
         }        public void windowOpened ( WindowEvent e ) {
         }

       public void windowClosed ( WindowEvent e ) {
       }

       public void windowClosing ( WindowEvent e ) {
          outerBox.setVisible ( false );
          outerBox.dispose ();
       }

       public void windowIconified ( WindowEvent e ) {
       }

       public void windowDeiconified ( WindowEvent e ) {
        }

}//end WhiteBoardApplet

GandhiServer2.java
----------------------------

import java.net.*;
import java.util.*;
import java.io.*;
public class GandhiServer2
{
   ServerSocket ss;
   Socket cs;
   Vector ht;
   ObjectInputStream ois;

   Socket skt;
   ObjectOutputStream oos;

   public GandhiServer2()
   {
       try
       {
           ss = new ServerSocket(9000);
           cs = ss.accept();

           while(true)
           {
               ois = new ObjectInputStream(cs.getInputStream());
               ht = (Vector)ois.readObject();

               if(!ht.isEmpty())
               {
                   try
                   {
                       skt = new Socket("localhost", 8000);
                       oos = new
ObjectOutputStream(skt.getOutputStream());
                       oos.writeObject(ht);
                       oos.close();
                   }
                   catch (Exception e)
                   {
                        e.printStackTrace();
                   }
               }

               System.out.println(ht);

               ois.close();
               ht.clear();
               cs.close();
               cs = ss.accept();
           }

       }
       catch (Exception e)
       {
           e.printStackTrace();
       }
   }

   public static void main(String[] args)
   {
       new GandhiServer2();
   }
}

The code above is a client server application. What the client does is
that it sends the coordinates of what is drawn on a canvas to the
server. The server will receive this coordinates and retransmit it to
all the clients connected to the server and display it on the canvas.
The client server concept work well, however after implementing this
concept, I cant see what I have drawn on the canvas, but it does send
the coordinates to the server.

How do I solve the problem.

Your help is kindly appreciated.

Regards.