The JSPProvider class reads in the JSP, compiles it, and runs it to produce the channel content.
The JSPProvider class reads at most three JSPs, one for content, one for the Edit page, and one to process the form submission from the Edit page. All other JSPs used in a JSP-based channel are referenced from one of those JSPs, either by an include or a forward statement.
A simple JSP-based channel can have just one JSP. Multiple JSPs are useful when a single part of the Desktop has to be replicated in several places. For example, consider a channel that has several display modes based on links clicked in that channel. Further, assume that the channel has a banner that must be displayed in all modes but one. You could construct a JSP to reference a banner.jsp file that captures common formatting that is used in multiple branches of the logic. If you didn’t use this method, you would need to duplicate the content from the banner.jsp file, which is more difficult to maintain if that content needs to be changed.