updated 08:30 pm EDT, Thu August 29, 2013
Keeping Java up-to-date can help avoid inconvenience
If Mac users already have Java installed, they may have a Java System Preference pane that can be used to update to the latest version. Otherwise, users will need to download and install the latest Java from Oracle's web page. User of OS X 10.6 can check Software Update to see if any new versions exist. Neither Apple nor Oracle support Java on machines running 10.5 or earlier, or on PPC-based Macs, and strongly advise owners of such machines to disable Java completely.
Apple has been advising users to enable Java in their web browser only when required to run a Java application. It also recommends that users confine the web browser to only the site that needs the Java plug-in, and not to open any other websites while the Java web plug-in is enabled. When finished with the website in question, the company suggests you disable the Java web plug-in. Apple itself automatically disables the plug-in when it hasn't been used in 30 days.
The security problems surrounding Java have become so serious that Apple was forced to take the unprecedented step of remotely disabling the plug-in to prevent the spread of malware and identity theft late last year, and have periodically had to re-block Java as new and serious security issues were uncovered. Java use on the Internet has dropped dramatically as a result of the issues, but many web sites still have Java-based web apps that can run in order to allow both Mac and Windows users access to the same programs.
Some gaming sites such as Pogo.com rely on Java (and Flash, which also has a long history of security issues) for their games. Users of such sites should be vigilant in remaining up-to-date on the latest versions of Java in order to avoid the inconvenience of blocked sites.