Can I permanently prevent Java security updates from installing Yahoo Toolbar?
Two points...
If you do not want the added software you only have two options.
Continue to uncheck the box and keep your automatic updates.
Use the offline installer at java.sun.com. The offline installer has not added software. If you are industrious or know someone excellent with batch files you could write a script to check their ftp servers, compare file names, download a new one if present and then do a silent install.
That's about it...
I'd write the batch file for you but I really don't know how. ;)
Here is help with silent installs - http://download.oracle.com/javase/1.4.2/docs/guide/plugin/developer_guide/silent.html
Maybe block toolbar.yahoo.com at the router?
I had to come down to my father's house to unblock his email client after he hit the wrong option in a firewall requester after updating the email client.
When I checked the link in the email he was waiting for I noticed the Yahoo toolbar that Java had sneaked into an update.
After removing it using the add-on system in Firefox, I added toolbar.yahoo.com to the blocked list in the router, I guess I'll find out if it worked next time they push an update.
I never install java... I just copy it and manually set it to my classpath and other variables as needed to start the application.
Of course I do not get auto updates... then again.. maybe I do not want auto updates ! This ensures that I remain in control of my deployed environment and as a bonus... My toolbars are free of yahoo junk !
then again... that does snot really answer the question though