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Webstart doesn't always recognize new jars available

Scott Presley

Joined: Apr 15, 2003
Posts: 25
I've been running webstart for a while in my test environment but we want to make the move to our production environment. I been having a problem with webstart not always recognizing that new jars are available.

Here is my process:
1. make changes to my application code
2. run ant to compile, jar, and sign my application and resource jars.
3. move the jars to the appropriate folder on the server, overwriting old jars
4. navigate to the web page that contains my launch button (link to my jnlp file)
5. first time launch button is clicked, application kicks off without updating jars.
6. close application and navigate back to the web page and click the launch button again.
7. webstart recognizes that updated jar are available and downloads the new jars before starting my application.

I did some poking around on the net and found a few resources, specifically this comment from the webstart FAQ at sun:

I don't want to rely on a server timestamp. How can I specify a versioned JAR and how can I get incremental updates of JARs?

Java Web Start supports versioned JARs and incremental updates. You can specify exact versions of the JAR files you want, instead of relying on timestamp information to determine if an update is available. Using version IDs also allows you to provide incremental updates from one version to another. See the JNLP Specification or the Developer's Guide for details.

I really haven't found anything in the developer's guide to detail how to version jar files. Does anyone know how to do this or at least know where i might find a resource that could explain this process?
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subject: Webstart doesn't always recognize new jars available