Oooh.. I don't recommend you incorporate a Java applet on your page unless it's the ONLY way to accomplish something (like the StormVue Java applet). Java is a major disincentive to viewers of a website as
1) it takes a loooonnnngggg time to load the Java engine (killing your first response to the website)
2) it's a fairly intense memory hog in the browser while running, and can slow down the viewers browser substantially.
If you want to let your viewers have a 'good' experience visiting your website, keep it simple and fast to load .. otherwise, they might not return... I have similar (negative) feelings about other applet controls (like Flash, Shockwave, audio players), especially if they're there only for the 'eye candy' and not for a needed purpose (slide shows of radar/map images, etc).
My (somewhat biased) opinion .. YMMV
Best regards,
Ken