Roy Tang

Programmer, engineer, scientist, critic, gamer, dreamer, and kid-at-heart.

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While testing our setup for user acceptance testing, we got some reports that java applets in our web application would occasionally fail to load. The envt where it was reported was WinXP/IE6, and there were no errors found in the java console.

Obviously we’d like to avoid it. What sort of things should we be checking for here? On our local servers, everything seems fine. There’s some turnaround time when sending questions to the on-site guy, so I’d look to cover as many possible causes as possible.

Some more info: We have multiple applets, in the instance that they fail loading, all of them fail loading. The applet jar files vary in size from 2MB to 8MB. I’m told it seems more likely to happen if the applet isn’t cached yet, i.e. if they’ve been able to load the applets once on a given machine, further runs on that machine go smoothly. I’m wondering if there’s some sort of network transfer error when downloading the applets, but I don’t know how to verify that.

Any advise is welcome!


Is it possible that there are version dependencies/mismatches with the JRE on the failing machines? I’ve had some situations with code that required Java 6 crashing browsers (Mac/Safari) that didn’t have it.

My experience with applets in an enterprise environment usually leads down 1 of 3 paths in regards to problems.

Incorrect or conflicting JRE versions on the client

Corrupt JRE on the client.

Corrupt IE Cache

I have found uninstalling a single JRE is usually not enough, Its often required to uninstall all JRE’s on the machine and reinstall only the ones you need.

Another trick is to reset their NT profile. This does wonders to correct IE cache issues as well. Done this so often I have documented the procedure. I generally perform this when a JRE uninstall reinstall doesnt work.

This can only be done by an administrator off the workstation. 
Meaning a user with Admin access cannot delete their own profile.

Before a user profile is deleted good practice is to back up the following folders found in: 
C:\Documents and Settings\<USERNAME>

My Documents

These folders could be copied to the user’s H:\ drive then can be copied back to the same folder
after the user logs back on to the system.

1.	Reboot the workstation. When you are back to the log on screen log in as the administrator.

2.	Right click on My Computer and choose properties.

3.	Choose the Advanced Tab then, under User Profiles, click on Settings.

4.	Highlight the user profile you would like to remove then click Delete. Close all the way out of the properties box.

5.	Go to Windows Explorer and navigate to C:\Documents and Settings. The folder named after the USERNAME
should have been removed. If it still remains manually delete the folder, 
then empty the recycling bin to make sure it’s been fully removed from the system.

6.	Reboot the workstation. At the log on prompt the user can log back in as themselves. 
This will create a brand new NT profile with their username. 
This will recreate certain OS settings as well as Internet Explorer settings 
that might have been corrupted in the old profile.

7.	At this point the three folders copied to the users H:\ drive can now be copied back to 
C:\Documents and Settings\<USERNAME>