Applet support has been greatly enhanced in Mac OS X version 10.2. Although there have been many individual bug fixes, the biggest change has been a re architecture of how applet support is provided as a whole. This is important information for both applet developers and developers of applications that display applets, usually Web browsers. The changes provide many requested benefits but may require a few changes on your part to take full advantage of them.
In versions of Mac OS X prior to version 10.2, applications that displayed applets, like Web browsers, used Mac OS X’s Java Embedding Framework to embed the java applets in the native application. The Java Embedding Framework itself used Sun's reference applet viewer class to provide access to the Java VM. Since the Java Embedding Framework did not use Sun’s Java Plug-in, the added functionality of the plugin was not available to applet developers or users. Since browser developers were required to use the Java Embedding Framework, they had to write special code to handle applets in their browsers for Mac OS X.
These issues have been addressed in Mac OS X version 10.2
by removing the emphasis from the Java Embedding Framework. Though
still there, it has been modified and should no longer be used for
new development by external developers. In its place Apple has introduced
the Java Applet.plugin for application developers.
This is a Netscape 4.0 style plugin that you should use if you are
building applications that need to display applets. For Applet developers,
Apple has replaced the usage of Sun's reference applet viewer with Sun’s
Java Plug-in. This gives you the added benefits of the plug-in like
Jar Caching and the Java Console. Java applet embedding application
developers should read “Modifying Applet Embedding Applications”. Applet developers should read “Taking Advantage of Sun’s Java Plug-in” respectively.
A related change is that Applet Launcher has moved to /Applications/Utilities/Java and also now uses the applet viewer from Sun's Java Plug-in to display applets. This is a change from previous versions of Mac OS X where Applet Launcher used Sun's reference applet viewer. If you want to test your applet using Sun's reference applet viewer, you may use /usr/bin/appletviewer.
Full documentation on Sun’s Java Plug-in is available at http://java.sun.com/products/plugin/1.3/docs/index.docs.html.
Taking Advantage of Sun’s Java Plug-in
Modifying Applet Embedding Applications