'Black Widow' is a common name used for rogue Java applets available in the WWW.
So far, no viruses written in Java or utilizing the Java holes in Netscape have been found. Other security problems have been located in Java applets, though.
Do not that 'Black Widow' is also a product name for a Java-based ORB (Object Request Broker) made by PostModern Computing. See the PostModern Computing website.
Depending on the settings of your F-Secure security product, it will either automatically delete, quarantine or rename the suspect file, or ask you for a desired action.
More information on the scanning and removal options available in your F-Secure product can be found in the Help Center.
You may also refer to the Knowledge Base on the F-Secure Community site for more information.