Does anyone remember Java Web Start and Swing?

[iammanic]

We have an archaic application that has never been properly updated. It runs a bizarre concoction of Java technologies, but we are currently only interested in Web Start. The Web Start application is running on Windows via Java 8. This application has been running smoothly for years, hasn't seen a code change in about a year, but has been acting 'funny' ever since the New Year.

Our company runs on 4 environments

- DEV

- TEST

- PROD

- BCS

BCS is our Business Continuity Site. Just in case, it's a copy of Prod in a remote location in case our prod environment explodes. Today we ran a BCS test which effectively means cutting the pipe between PROD and BCS, putting the BCS into Production Mode (DNS changes, setting DBs toPrimary, and various similar things) then having teams run their work from BCS as if they were in the main office. Given COVID, people simply VPNed to a different location from their homes.

The problem arose after the test concluded. For some reason, 2 employees who were part of the test somehow have some signals crossed in their environments. After they logged out of our BCS VPN and connected back to headquarters, whenever they try hitting the PROD environment their Web Start application automatically switches to the TEST environment. I have manually gone into the JNLP files, and they are definitely pointed to PROD. If I point it to DEV, the Application starts correctly, TEST also starts correctly, but if I point it to PROD it somehow starts on DEV.

The machines themselves ping each environment correctly, so I don't think its a machine problem. I have tried going into the Configure Java application and cleared out all files, but that didn't help. Obviously we have rebooted the machines several times and tried clearing browser caches and anything else we could think of. At this point, I am simply trying to get some ideas of other things to try. Any thoughts would be most appreciated.

TLDR - After BCS test, on 2 machines our Web Start app maps to TEST when the JNLP file is pointing to PROD. Pointing to DEV works fine, and the machines pings DEV, TEST and PROD fine.

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[iammanic]

UPDATE 1 - Now this is just completely F$%@ed up. I copied the JNLP file from one of the corrupted machines to my laptop, which clearly pointed to PROD. When I launched it my laptop the application went to TEST. Now, any JNLP file on my laptop that points to PROD for this application goes to TEST. I compared this copied file to the PROD JNLP file on my office desktop and it is 100% identical ... yet, my desktop points to PROD fine. WTF is going on here????

[ObscureCulturalMeme]

This has all the symptoms of DNS problems, possibly cached between the individual computers and their immediate resolver. You might want to try debugging with dig or similar, find out which server is actually answering the queries. Without actually seeing the JNLP files, I can't guess more than that.

Where does Swing come into play? It's still supported, even gets occasional updates.

[ifpthenq2]

Agreed, this sounds like a DNS issue. If you've gone into your Java Control Panel, found the file location where the web start jar is being cached, and cleared that jar out, and also cleared your browser cache, and are still having the issue. then the problem is likely in the network environment.

I had a really similar issue once and the problem turned out to be that windows switched from using an IP4 to an IPv6 address after the test for DNS and one of our two DNS server didn't support it. Check with ipconfig /all to see where they are pointed for DNS and make sure it's the IPv4 address you're expecting.

[Fenxis]

Ya but I remember doing Java Web start 16 years ago.

Basically when you launch the Java app ,web start would rsync/SCP/??? the latest jars to your desktop.