Currently, signed applets are hard to work with for two reasons:
Each of the large browser vendors uses a different format for signed applets.
Code signing tools are buggy.
You can compensate for the first problem, on the server side, by detecting the type of client browser and returning a page containing a browser-specific applet. (Yuck!) You can compensate for the second problem by sweating a lot and tearing your hair out. If your application design relies on signed applets, you should think long and hard before proceeding. Chapter 12, discusses some popular application architectures and the pros and cons of using an applet as a client. If you are developing an application in a partly closed environment, where you know that only one brand of browser will be used, then signed applets may be practical.
As this book goes to press, an interesting alternative technology is emerging: Sun’s Java Activator. This is a Java Runtime Environment (JRE) that runs as a plug-in or extension with Netscape Navigator and Internet Explorer. Basically, it enables applets to use Sun’s JVM instead of Netscape’s, or Microsoft’s. Signed applets are supported in Activator, but the exact technique is evolving. Check the documentation for details.
Furthermore, it’s not clear what will happen to Navigator vis-a-vis Java, now that Navigator is free and the source code will be published. Netscape has stated that it will no longer produce a JVM, instead making the browser accept any JVM developed by Sun or ...