What are the main differences between JavaBeans and applets?
Applets are Java programs which are meant to be run by an applet-runner (which is typically inside a web browser). By definition, applets are applets because they inherit from java.applet.Applet. Also, applets are pretty constrained in what they are/aren't allowed to do.
Traditional JavaBeans are Java software components. A bean may be a single, simple, standalone class or it may be a complicated behemoth but, as long as it follows the rules and conventions of JavaBeans, then it's a JavaBean.