Client Browser Hangs When Running an Instrumented Applet

Problem

Client browser stops responding when the user navigates away from a certain Web pages. The affected client is using Internet Explorer with the 1.5.0 Java plug-in, and the IWSVA Applet and ActiveX Security scanning module is enabled, and Allow... Destructive Operations option is disabled (HTTP > Applets and ActiveX > Policies | Java Applet Security Rules).

Reason

Applet and ActiveX Security includes an option to detect and respond to potentially harmful Java commands, including stop() and destroy(). When a Java applet uses one of these commands to terminate itself, it may cause a conflict with Applet scanning that presents as an unresponsive browser.

Solution

There are four ways you can work around this issue:

Instruct your users to use a different browser (such as Firefox or Opera) to run the applet.
Exempt the page containing the applet from scanning by adding its address to the IWSVA trusted URL list: HTTP > URL Access Control > Global Trusted URLs.

Caution: Content received from URLs on this page is not scanned or filtered.

Prevent clients from accessing the page by adding it to the URL blocking list: HTTP > URL Access Control > Global URL Blocking | via Local List (clients will receive a notification message in their browser instead of the page).
"Dial-down" the instrumentation threshold in the policy settings to a level that allows the applet code to pass scanning.

Note: because the instrumentation level settings are policy wide, use caution if choosing this option and test some sample pages with a limited number of users to determine exactly which restrictions are involved (there may be more than one).
Tip: When running the applet under Internet Explorer, open the Java Console (Tools > Sun Java Console) and examine the output for clues about what the applet was trying to do at the time of the hang.