The java source code (showflip.java) is shown below.

//***********************************************************************
//
// showflip.applet 11/21/2001
//
// by: parks@uh.edu
//
//
//***********************************************************************

import java.applet.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.net.URL;
import java.awt.image.*;
import java.awt.Graphics.*;

public class showflip extends Applet implements Runnable, ItemListener,  AdjustmentListener


{
private boolean isRunning = false;
private int cur;
private int swidth, sheight;        // windows sizes
private Image flipimage;       // 320x240 3d window
private Graphicsg_handle;//graphics handle for 3d window
Image memSprite[]=new Image[51]; // vector of memory image sprites
private String load_string = "Loading Image: "; // loading string appears in 3d window
private String fn;  //file name string
private String intpart; //integer part of fn string
private int itemp;
private int fb;
private int waittime;   // delay between frame display
private String delaystring;
private Thread showflip_thread = null;
public CheckboxGroup forw_back_radios; // checkbox group id for flip forward or backwards
public Checkbox frad; // checkbox for forward flip
public Checkbox brad; // checkbox for backward flip
public Scrollbar flipspeed;   //scrollbar for speed choice
public Label slowertext;
public Label fastertext;
public Label msspeed;


public showflip ()
{

}
public String getAppletInfo()
{
return "Name:showflip\r\n"+"Author: Parks";

}
public void init()
{
              CheckboxGroup forw_back_radios = new CheckboxGroup();
              Checkbox frad = new Checkbox ("Front", false, forw_back_radios);
              Checkbox brad = new Checkbox ("Back", true, forw_back_radios);

              flipspeed = new Scrollbar(Scrollbar.HORIZONTAL,25,5,0,105);

              fastertext = new Label("Faster",Label.LEFT);
              slowertext = new Label("Slower Delay=",Label.LEFT);
              msspeed = new Label ("25ms",Label.LEFT);

              setForeground(Color.black);
              swidth=340;
              sheight=300;
              setLayout(new FlowLayout(FlowLayout.LEFT,0,0));

              add (frad);
              frad.addItemListener(this);

              add (brad);
              brad.addItemListener(this);

              add(fastertext);
              add(flipspeed);
              flipspeed.addAdjustmentListener(this);
              add(slowertext);
              add(msspeed);

              flipimage = createImage(swidth,sheight);

              g_handle = flipimage.getGraphics();

              if (showflip_thread == null)
                {
                 showflip_thread = new Thread(this);
                 showflip_thread.start();
                 }
               isRunning = true;// set applet switch to on

} // end init

public void destroy()
{
}
public void update( Graphics g )
{
    paint( g );
}
public void paint(Graphics g)
{
    if ( isRunning ) //draw the current image
      {
       g.drawImage(flipimage,0,0,this );
      }
}
public void start()
{
              cur=1;
              fb=2;
              waittime=25;
}
public void stop()
{
   if (showflip_thread != null ) // && showflip_thread.isAlive() )
      {
        showflip_thread.stop();
        showflip_thread = null;
       }
}
public void run()
{

Color ltgray = new Color(192,192,192);
g_handle.setColor( ltgray );
g_handle.fillRect( 0, 0, 360, 300 );
repaint();
for (itemp=0 ; itemp < 51 ; itemp++)
   {
    if (itemp==0)  //****** load and display title image
      {
         memSprite[0]=ImageLoader( getDocumentBase(), "cflip.gif" );
         g_handle.drawImage( memSprite[0], 20, 40, this );
         repaint();
      }
    else           //*** set wait times, build file names and load them
      {
        if (itemp < 10) fn="cfli000";
        if (itemp >=10 && itemp <100) fn="cfli00";
        fn=fn+Integer.toString(itemp);
        intpart=load_string+Integer.toString(itemp)+" of 50";
        fn=fn+".gif";
        g_handle.setColor( Color.blue);
        g_handle.drawImage( memSprite[0], 20, 40, this  );
        g_handle.drawString(intpart,25,100);
        repaint();
        memSprite[itemp]=ImageLoader( getDocumentBase(), fn );
       }
}
while (true)
{
  try
     {
       if ( isRunning )
         {
          g_handle.drawImage( memSprite[cur], 20, 40, this);
         }
        repaint();
        if (cur == 1)
           {
            Thread.sleep(1000);
           }
        else
          {
           Thread.sleep(waittime);
          }
        if(fb == 2) //***forward back
          {
           cur=cur+1;
           if (cur > 50) cur = 1;
          }
        else    //**** backward flip
          {
           cur=cur-1;
           if (cur <1) cur=50;
          }
      }
      catch (InterruptedException e)
         {
           stop();
         }
}

} //end run
private Image ImageLoader( URL url, String sFilename )
{
  MediaTracker tracker = new MediaTracker( this );
  Image img = getImage( url, sFilename );
  tracker.addImage( img, 0 );
  try
   {
     tracker.waitForAll();
    }
   catch (InterruptedException e) {}
    return img;
}
public void itemStateChanged(ItemEvent event)
{
//
//process the flip choice
//
  String iselect;
  iselect=event.getItem().toString();
  if(iselect.equals("Front"))
    {
      fb=1;
      cur=1;
    }
  if(iselect.equals("Back"))
    {
     fb=2;
     cur=50;
    }
} //**** end forward backward radios

public void adjustmentValueChanged(AdjustmentEvent event)
     {
//
//   process the slider adjustment
//
     waittime=flipspeed.getValue();
     delaystring=String.valueOf(waittime);
     delaystring=delaystring.trim();
     msspeed.setText(delaystring+"ms");
     }
}//end applet