Yes, I know this isn't game-specific but this topic came up in game chat today and met with various reactions so the least I can do is to place the facts before you all and you can make whatever decision you consider relevant to your own machine. Suffice to say that Java is not installed on any machines here and, especially if you do anything of a financial nature with your PC (online shopping or banking, for example), you may share my opinion that it just is not worth the risk.
As the article to which I am linking below says,
"Time and time again we're seeing examples of cybercriminals exploiting flaws in Java to infect innocent users' computers.
For instance, earlier this year we saw more than 600,000 Macs infected by the Flashback malware because of a Java security flaw.
In fact, it has become increasingly common to see malware authors exploiting vulnerabilities in Java - as it is so commonly installed, and has been frequently found to be lacking when it comes to security.
Cybercriminals also love Java because it is multi-platform - capable of running on computers regardless of whether they are running Windows, Mac OS X or Linux. As a result it's not unusual for us to see malicious hackers use Java as an integral part of their attack before serving up an OS-specific payload."
Full article at: http://nakedsecurity.sophos.com/2012/08/30/how-turn-off-java-browser/
(Note: Java is not the same as Javascript.)
Though I don't use Sophos software, the Naked Security blog is excellent for remaining informed about current threats.