For what it's worth here is a warning from the Department of Homeland Security:
The Department of Homeland Security is urging computer users to disable or uninstall the Java programming language because of a serious security vulnerability.
The flaw in Java 7 "can allow a remote, unauthenticated attacker to execute arbitrary code on a vulnerable system," according to a warning posted Thursday by the U.S. Computer Emergency Response Team (CERT).
Hundreds of millions of consumers and businesses may be affected.
Hackers could exploit the flaw to install malicious software or malware that could make users vulnerable to identity theft or allow their computers to be exploited by "botnets" that could crash networks or be used to attack web sites.
"Note that applications that use the Internet Explorer web content rendering components, such as Microsoft Office or Windows Desktop Search, may also be used as an attack vector for this vulnerability," the warning adds.
DHS said it is "currently unaware of a practical solution to this problem." [USA Today]
Of course if you do disable it or delete it, you may not be able to use many websites nor engage in chat. You better call your computer folks before taking any drastic action, but at least now you have been warned.