Apple has released an update to Safari for OS X 10.6 users which, along with the latest Java updates, gives Snow Leopard users the ability to enable Java on a site-by-site basis.
This news is in response to the development of the Java runtime that has moved it past official support for Snow Leopard. While the latest version of Java Apple developed (Java SE 6) is supported in Snow Leopard, support for this version of OS X ended when Apple passed the baton to Oracle to maintain Java.
With Java SE 7 requiring OS X 10.7 or later, unfortunately Snow Leopard users will not be able to benefit from new features, including security implementations, that will be developed into the runtime by Oracle. Therefore, instead of requiring these users to disable Java completely and then continue toggling it on and off to enable content for sites they visit, Apple has implemented a new site-specific Java feature that will allow users to enable the Java plugin only for Web sites they trust.
This new feature requires two updates Apple has just released for Java and for Safari, which are available through the Software Update service in OS X that can be accessed from the Apple menu.
The updates are about 100MB combined, and once installed, you can manage Java for each Web site by first opening a site with Java content, where you will see a notice about the site containing a Java applet, with options to block or allow the applet. If you see a standard "blocked plug-in" message where the Java content is, you will still be able to manage the java content, but will first need to update Java to the latest version.
Once the site has been visited, go to the Security section of Safari's preferences and click the new "Manage Website Settings..." button that is next to the "Allow Java" checkbox. In the drop-down panel that appears, you will see the recently visited site, which Safari will set to request permission to view Java content by default. In here you can click the setting to allow, always allow, or always block the Java content.
This feature is new for Snow Leopard, but is also available for those running Java SE 6 in OS X Lion.