Running under MacOS
Testing this applet for MacOS, we found that it can run well under certain circumstances. The only problem we had was with Netscape 3.xx. The best Mac "virtual machines" appear to be the most recent, not surprisingly. The Apple MRJ virtual machine, which runs on MacOS 7.6.1 and later, is available at developer.apple.com/java It currently works as an optional VM under Internet Explorer 3 and 4 for Macintosh. The Netscape 5.0 browser is supposed to support this sort of configuration as well. In the mean time, Netscape's 4.xx browsers, available at netscape.com seem to handle Java well enough under System 8.5.
The earlier Macs, based on the 68x000 architecture are not very Java compatible. Likewise, MacOS prior to System 7.6.1 seems to be fairly hostile to Java.
The GraphicJam applet works fine under IE 4, Mac OS 8.5, running either the Microsoft or the Apple MRJ 2.0 virtual machines. It was tested under both a 604 PowerPC and a G3 machine. Netscape 4.5 and 4 also worked fine on these machines. In general, the older your computer, system, and browser, the less compatible you're likely to be with advanced Java functionality. Good luck!