How do I allow offline use AND check for updates if online?

Question

I am actually not sure if this is a bug or not, as the behavior changed when I updated from 1.6u20 to u21. I have an application in a single JAR, and a JNLP file. I am testing with Windows 7 64-bit (with both the 32- and 64-bit version of the JVM installed, 1.6u20-b06 on both). The application cache is enabled. Here is my JNLP file:
<?xml version="1.0" encoding="us-ascii"?>
<jnlp
  spec="6.0+"
  codebase="http://hidden"
  href="Librarian.jnlp">
  <information>
    <title>Librarian</title>
    <vendor>Vendor</vendor>
    <homepage href="http://hidden"/>
    <description>Description.</description>
    <offline-allowed/>
    <shortcut online="false">
      <desktop/>
      <menu submenu="Vendor"/>
    </shortcut>
    <icon href="Librarian.gif"/>
  </information>
  <security>
    <all-permissions/>
  </security>
  <resources>
    <j2se version="1.6+"/>
    <jar href="Librarian.jar" main="true"/>
  </resources>
  <application-desc main-class="com.vendor.apps.librarian.Librarian"/>
</jnlp>I am observing the following behavior wrt updates and allow-offline:
When allow-offline is present:
- JWS does not download updates to the JAR file when the desktop link is clicked.
- The application can run when I disable the network connection.
- The "-offline" switch is passed to javaw in the desktop shortcut.
When allow-offline is not present:
- JWS does download JAR updates when the desktop link is clicked.
- The application can not run when I disable the network connection (HostNotFoundException).
- The "-offline" switch is not passed to javaw in the desktop shortcut.
What I want to happen is for JWS to check for updates if it can, and if it times out, instead of barfing, just go ahead and run the cached version. What I can get right now is either no updates + offline allowed, or updates + offline disallowed. However, I can obtain the behavior I want if I specify allow-offline then hand-edit the desktop shortcut and remove "-offline":
When allow-offline is present but I remove "-offline" from the desktop shortcut:
- JWS does download updates to the JAR file.
- The application can run when I disable the network connection, after a short timeout.
Now, I was under the impression that this behavior is the intended behavior of allow-offline: attempt to download update, on error, silently start the cached version instead. This does not seem to be the case. I actually wonder if this is a bug, as with 1.6u20, it seemed to download JAR updates just fine when allow-offline was specified (I had issues when the cache was disabled with 1.6u20, and so I moved to u21).
How can I make this work the way I want without having to hand edit the desktop shortcut?
Is this a bug, or am I misconfiguring (OED says this is a real word!) the application?
Is there something else I have to do to indicate that the JAR is updated besides just uploading a new version to the server?
It should be noted that I am not doing any web page magic here, I'm testing by simply downloading the JNLP file off the server and opening it. This is actually my first JWS experience and I haven't gotten to properly embedding it in a web page yet. I do not know if this is significant or not.
Thanks!
M

Answer 1

Well, I solved that quick. I've been staring at it for over an hour but it popped out at me as soon as I looked at my JNLP file in my post here (guess it's the red text, heh).
All I need to do is set online="true" in the shortcut, and also specify allow-offline, and all works exactly as I want it to. :-)
Perhaps it was a bug in u20 that was causing it to check for updates anyways even with an offline shortcut... I'm not sure, and I don't have it in me to test it any more at the moment.
Thanks,
M