If you have not yet seen or acted upon Homeland Security's warning, I urge you to do so immediately:

The U.S. Department of Homeland Security is advising people to temporarily disable the Java software on their computers to avoid potential hacking attacks.  The recommendation came in an advisory issued late Thursday, following up on concerns raised by computer security experts.

BlazingCatFur explains the situation:

My suspicion is that it's related to this: Iran blamed for massive cyber attack on U.S. banks data centers as 'puppet hacking group' says they did it because the anti-Mohammed movie is still on the internet.

BCF links to a helpful site, but the instructions may be a bit confusing to some:

Last month Oracle released a new Java version, Update 10, that includes a one-stop option for disabling Java in all browsers in the Java Control Panel. Open Control Panel and launch the Java applet. If you don't see it, switch to Classic View (in XP) or small icons (in Vista or Windows 7). Click the Security tab. In previous versions this tab just allowed advanced users to manage Java-related certificates. It now displays a security-level slider and, more important, a single checkbox titled "Enable Java content in the browser." Un-check this box, click OK, and you're done.

I suggest just uninstalling Java from the Control Panel and then restarting your computer. No Java, no Problem!

For Windows, click Start (1) on your taskbar, then control panel (2), then Programs and Features (3), then find Java (4), then click to uninstall (5):