Applet only works with one Java version

[Rob Spoor]

I've written an applet inside a signed JAR (needs a lot of OS interaction) which works perfectly in Java 1.4.2, which it's also written in.

However, when I try it with different Java versions (1.4.1 and 1.5 are tested) I get the following error:

Java(TM) Plug-in: Version 1.4.1_03
Using JRE version 1.4.1_03 Java HotSpot(TM) Client VM
User home directory = C:\Documents and Settings\h.meeuwisse
Proxy Configuration: No proxy
 
----------------------------------------------------
c:   clear console window
f:   finalize objects on finalization queue
g:   garbage collect
h:   display this help message
l:   dump classloader list
m:   print memory usage
o:   trigger logging
p:   reload proxy configuration
q:   hide console
r:   reload policy configuration
s:   dump system properties
t:   dump thread list
v:   dump thread stack
x:   clear classloader cache
0-5: set trace level to <n>
----------------------------------------------------
java.io.IOException: Server returned HTTP response code: 401 for URL: <a href="http://xbox/ivrviewer/sivrviewer.jar" target="_blank" rel="nofollow">http://xbox/ivrviewer/sivrviewer.jar</a>
            at sun.net.www.protocol.http.HttpURLConnection.getInputStream(Unknown Source)
            at sun.plugin.net.protocol.http.HttpURLConnection.getInputStream(Unknown Source)
            at sun.plugin.net.protocol.http.HttpUtils.followRedirects(Unknown Source)
            at sun.plugin.cache.CachedJarLoader.isUpToDate(Unknown Source)
            at sun.plugin.cache.CachedJarLoader.loadFromCache(Unknown Source)
            at sun.plugin.cache.CachedJarLoader.load(Unknown Source)
            at sun.plugin.cache.JarCache.get(Unknown Source)
            at sun.plugin.net.protocol.jar.CachedJarURLConnection.connect(Unknown Source)
            at sun.plugin.net.protocol.jar.CachedJarURLConnection.getJarFile(Unknown Source)
            at sun.misc.URLClassPath$JarLoader.getJarFile(Unknown Source)
            at sun.misc.URLClassPath$JarLoader.<init>(Unknown Source)
            at sun.misc.URLClassPath$3.run(Unknown Source)
            at java.security.AccessController.doPrivileged(Native Method)
            at sun.misc.URLClassPath.getLoader(Unknown Source)
            at sun.misc.URLClassPath.getLoader(Unknown Source)
            at sun.misc.URLClassPath.getResource(Unknown Source)
            at java.net.URLClassLoader$1.run(Unknown Source)
            at java.security.AccessController.doPrivileged(Native Method)
            at java.net.URLClassLoader.findClass(Unknown Source)
            at sun.applet.AppletClassLoader.findClass(Unknown Source)
            at sun.plugin.security.PluginClassLoader.findClass(Unknown Source)
            at java.lang.ClassLoader.loadClass(Unknown Source)
            at sun.applet.AppletClassLoader.loadClass(Unknown Source)
            at java.lang.ClassLoader.loadClass(Unknown Source)
            at sun.applet.AppletClassLoader.loadCode(Unknown Source)
            at sun.applet.AppletPanel.createApplet(Unknown Source)
            at sun.plugin.AppletViewer.createApplet(Unknown Source)
            at sun.applet.AppletPanel.runLoader(Unknown Source)
            at sun.applet.AppletPanel.run(Unknown Source)
            at java.lang.Thread.run(Unknown Source)
java.io.IOException: Server returned HTTP response code: 401 for URL: <a href="http://xbox/ivrviewer/sivrviewer.jar" target="_blank" rel="nofollow">http://xbox/ivrviewer/sivrviewer.jar</a>
            at sun.net.www.protocol.http.HttpURLConnection.getInputStream(Unknown Source)
            at sun.plugin.net.protocol.http.HttpURLConnection.getInputStream(Unknown Source)
            at sun.plugin.net.protocol.http.HttpUtils.followRedirects(Unknown Source)
            at sun.plugin.cache.CachedJarLoader.isUpToDate(Unknown Source)
            at sun.plugin.cache.CachedJarLoader.loadFromCache(Unknown Source)
            at sun.plugin.cache.CachedJarLoader.load(Unknown Source)
            at sun.plugin.cache.JarCache.get(Unknown Source)
            at sun.plugin.net.protocol.jar.CachedJarURLConnection.connect(Unknown Source)
            at sun.plugin.net.protocol.jar.CachedJarURLConnection.getJarFile(Unknown Source)
            at sun.misc.URLClassPath$JarLoader.getJarFile(Unknown Source)
            at sun.misc.URLClassPath$JarLoader.<init>(Unknown Source)
            at sun.misc.URLClassPath$3.run(Unknown Source)
            at java.security.AccessController.doPrivileged(Native Method)
            at sun.misc.URLClassPath.getLoader(Unknown Source)
            at sun.misc.URLClassPath.getLoader(Unknown Source)
            at sun.misc.URLClassPath.getResource(Unknown Source)
            at java.net.URLClassLoader$1.run(Unknown Source)
            at java.security.AccessController.doPrivileged(Native Method)
            at java.net.URLClassLoader.findClass(Unknown Source)
            at sun.applet.AppletClassLoader.findClass(Unknown Source)
            at sun.plugin.security.PluginClassLoader.findClass(Unknown Source)
            at java.lang.ClassLoader.loadClass(Unknown Source)
            at sun.applet.AppletClassLoader.loadClass(Unknown Source)
            at java.lang.ClassLoader.loadClass(Unknown Source)
            at sun.applet.AppletClassLoader.loadCode(Unknown Source)
            at sun.applet.AppletPanel.createApplet(Unknown Source)
            at sun.plugin.AppletViewer.createApplet(Unknown Source)
            at sun.applet.AppletPanel.runLoader(Unknown Source)
            at sun.applet.AppletPanel.run(Unknown Source)
            at java.lang.Thread.run(Unknown Source)
load: class com.hecc.ivr.viewer.ViewerApplet not found.
java.lang.ClassNotFoundException: com.hecc.ivr.viewer.ViewerApplet
            at sun.applet.AppletClassLoader.findClass(Unknown Source)
            at sun.plugin.security.PluginClassLoader.findClass(Unknown Source)
            at java.lang.ClassLoader.loadClass(Unknown Source)
            at sun.applet.AppletClassLoader.loadClass(Unknown Source)
            at java.lang.ClassLoader.loadClass(Unknown Source)
            at sun.applet.AppletClassLoader.loadCode(Unknown Source)
            at sun.applet.AppletPanel.createApplet(Unknown Source)
            at sun.plugin.AppletViewer.createApplet(Unknown Source)
            at sun.applet.AppletPanel.runLoader(Unknown Source)
            at sun.applet.AppletPanel.run(Unknown Source)
            at java.lang.Thread.run(Unknown Source)
Caused by: java.io.IOException: open HTTP connection failed.
            at sun.applet.AppletClassLoader.getBytes(Unknown Source)
            at sun.applet.AppletClassLoader.access$100(Unknown Source)
            at sun.applet.AppletClassLoader$1.run(Unknown Source)
            at java.security.AccessController.doPrivileged(Native Method)
            ... 11 more

The class is com.hecc.ivr.viewer.ViewerApplet.
I haven't used any special Manifest to create the JAR, which is signed using a local keytool.

The HTML code:

<object classid="clsid:8AD9C840-044E-11D1-B3E9-00805F499D93" width="800" height="600"
        codebase="http://java.sun.com/products/plugin/autodl/jinstall-1_4_1_03-windows-i586.cab#Version=1,4,0,0">
  <param name="code" value="com.hecc.ivr.viewer.ViewerApplet">
  <param name="archive" value="sivrviewer.jar">
  <param name="name" value="IVRApplet">
  <param name="type" value="application/x-java-applet;version=1.4">
  <embed src="sivrviewer.jar" width="800" height="600" code="com.hecc.ivr.viewer.ViewerApplet"
         archive="sivrviewer.jar" name="TimePicker" type="application/x-java-applet;version=1.4">
</object>

This installs Java 1.4.1_03 (most users have that one) if no newer version is installed - if I replace it with 1.4.2_06 (the version used to compile) it still does not work.

Anyone know how I can solve this without requiring Java 1.4.2?

[Ernest Friedman-Hill]

HTTP response code 401 is "Unauthorized". Are you sure this is a Java version thing, and not a security thing? Is the web server where the applet lives allowed to send to JAR file to the client machine you're testing on?

[Rob Spoor]

You know, that is a good question.
The web directory it is in now has IIS security on it, so that might be the problem. If so, question is why 1.4.2 does work.

I'll test this tomorrow on my test server (IIS but no security).

[Rob Spoor]

Ok, security is the problem, and only in Java 1.4.1 - even a machine with only 1.5 worked (although I had to login twice).

Guess I'll have to change the HTML page to require 1.4.2_06 as the minimum.