At least in Netscape Navigator on Solaris, 
Java Plug-in does not load images from JAR
files.

For the tutorial, we've worked around this
(PARTLY) by including the image files alongside
the JAR files.  But this wastes disk space and
bandwidth, and it DOES NOT WORK across firewalls.
(I think the firewall is what prevents image files
from being loaded separately, but the cause might
be something else; the result is the same, though.)

This is a major bug that degrades applet performance
and discourages the use of images in applets.  Worse,
since it doesn't show up all the time, developers 
might miss this bug until they've deployed their
applets, which is likely to make them very angry
at us.

Name: gsC80088			Date: 02/26/99


I have an applet that works fine under Java 1.1.6 but not
under 1.2. When the applet starts it first displays a splash
screen. The splash screen also allows the user to enter their
user name and password in two TextField objects that are placed
on top of the graphic. Labels are drawn beside these text fields
while they are visible. As soon as the OK button is pressed 
the OK and Cancel button that appear under the text fields are
hidden, as are the text fields.

The class file for the applet is in one Jar file
(TstProg5.jar) and the code for displaying the splash screen
is part of a set of support classes in another Jar file
(Exodus.jar). The splash screen graphic is in the same Jar
file as the splash screen class. Both components are in the
directory 'Exodus' within the Exodus.jar file.

The splash screen image, together with an animated activity
bar are loaded using the following code:

  private void imageInit()
  {
       MediaTracker mt = new MediaTracker(this);

       System.out.println("Loading graphics");

       splash = parent.getImage(parent.getDocumentBase(), "Exodus/Splash.jpg");
       anim = parent.getImage(parent.getDocumentBase(), "Exodus/Animbar.jpg");

       mt.addImage(splash, 0);
       mt.addImage(anim, 0);
       buffer = createImage(481, 320);
       gc = buffer.getGraphics();

       try
       {
	   mt.waitForAll();
       }
       catch (InterruptedException e)
       {
           System.out.println("Interrupted waiting for creation of image");
       }

       System.out.println("Splash = " + splash.toString());

  } // End loadImage

The System.out.println call at the end of the method displays
the following:

    Splash = sun.awt.windows.WImage@f981df62

so the image is instantiated to something. Also there is a
delay between the "Loading graphics" message and the "Splash ="
message that is appropriately long for the size of the graphics
and the speed of our network. When the paint routine is called
(which happens in a loop to animate the activity bar) no
graphics appear. The paint routine is shown below:

  public void paint(Graphics g)
  {
    try
    {
       gc.drawImage(splash, 0, 0, this);
       if(displayComps)
       {
           gc.setFont(scrnFont);
           gc.setColor(Color.white);
           gc.drawString("Login Id:", 80, 160);
           gc.drawString("Password:", 80, 195);
       }
       else
       if(animating)
       {
           gc.drawImage(anim, animXpos + 468, 294, this);
           gc.drawImage(anim, animXpos, 294, this);
           if(animXpos < 455)
               gc.drawImage(anim, animXpos + 936, 294, this);
       }
       g.drawImage(buffer, iset.left, iset.top, this);
    }
    catch (NullPointerException e) {}

  } // End paint

Again, this works fine under JDK 1.1.6 and the JRE run time
using the Java Plugin.
======================================================================

Name: rlT66838			Date: 03/02/2000


Java(TM) Plug-in: Version 1.2.2.p001
Using JRE version 1.2.2
  User home directory = D:\WINNT\Profiles\prd
Proxy Configuration: no proxy

JAR cache enabled.
Opening http://ip200/cursbug.jar no proxy
CacheHandler file name: D:\WINNT\Profiles\prd\Temporary Internet
Files\G97J7G22\cursbug.jar

1. a)place cursbug.jar and CursorBug.htm on Web Server
   b)Open CursorBug.htm in Web Browser
   c)Cursor disappears when entering JApplet
*Make sure to remove CustomCursorBug.class and jarImage.class from you local
path or bug will not appear.
**The Cursor.gif file is CompuServer Graphics Interchange file version 89a
Noninterlaced (Size:32x32) 4bit(16 Color) with a transparent background.
2.
a)FILE:CustomCursorBug.java
import javax.swing.JApplet;
import java.awt.Cursor;
import java.awt.Image;
import java.awt.Toolkit;
import java.awt.Point;
public class CustomCursorBug extends JApplet{
  public CustomCursorBug(){
  }
  public void init(){
    super.init();
    jarImage ji = new jarImage();
    Image cursorImage = ji.getImageFromJAR("images/Cursor.gif");
    Cursor customCursor =
  Toolkit.getDefaultToolkit().createCustomCursor(cursorImage,new
Point(1,1),"Custom");
		setCursor(customCursor);
  }
}
b)jarImage.java
import java.awt.*;
import java.io.InputStream;

public class jarImage {
    public jarImage() { }
    // returns an Image retrieved from a jar file
    public Image getImageFromJAR(String fileName){
      if( fileName == null )
        return null;
      Image image = null;
      byte[] tn = null;
      Toolkit toolkit = Toolkit.getDefaultToolkit();
      InputStream in = getClass().getResourceAsStream(fileName);
      try{ int length = in.available();
        tn = new byte[length];
        in.read( tn);
        image = toolkit.createImage( tn);
      }
      catch(Exception exc){
        System.out.println( exc +" getting resource " +fileName );
        return null;
      }
      return image;
    }
  }
c)FILE:CursorBug.htm
<html>
<head>
<title>Cursor Bug</title>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
</head>
<body bgcolor="#FFFFFF">
<object classid="clsid:8AD9C840-044E-11D1-B3E9-00805F499D93"
    width = 100
    height = 100
  
codebase="http://java.sun.com/products/plugin/1.2.2/jinstall-1_2_2-win.cab#Versi
on=1,2,2,0">
  <param name=CODE value = CustomCursorBug.class >
  <param name=ARCHIVE value="cursbug.jar">
  <param name="type" value="application/x-java-applet;version=1.2">
  <param name="scriptable" value="false">
  <embed
    type="application/x-java-applet;version=1.2"
    code = CustomCursorBug.class
    archive="cursbug.jar"
    width=100
    height=100
    pluginspage="http://java.sun.com/products/plugin/1.2.2/plugin-install.html"
    scriptable=false>
    <noembed></COMMENT> alt="Your browser understands the &lt;APPLET&gt; tag but
    isn't running the applet." Your browser is completely ignoring
    the &lt;APPLET&gt; tag! </noembed>
  </embed>
</object>
</body>
</html>
3)No error reported
4)N/A
5)N/A
(Review ID: 101296)
======================================================================