"An applet is a program written in the Java programming language that can be included in an HTML page, much in the same way an image is included in a page. When you use a Java technology-enabled browser to view a page that contains an applet, the applet's code is transferred to your system and executed by the browser's Java Virtual Machine (JVM)", quoted from Java.sun.com.
See following panorama and virtual tour sample:
Java-supported panorama made by Panoweaver
Java-supported virtual tour made by Tourweaver
Besides Java-supported output, Panoweaver also publishes Flash and Quicktime format tours, while Tourweaver also supports Flash and video tours.
Download full featured trial version of Panoweaver and Tourweaver!