When a JSP file is executed, it is first scanned by OpenCms. All files that point to the VFS are adjusted and then resources are copied to the real file system (into online or offline under $CATALINA_HOME/webapps/opencms/WEB-INF/jsp/). The JSP engine then parses the files into Java sourcecode, which it compiles into servlet class files. The FlexCache mechanism caches the results of dynamic elements (e.g. navigation) to expedite subsequent requests for the same content. FlexCache uses a Least Recently Used (LRU) policy, which maintains the most requested items in the cache while bumping out items that are not requested very often. The result is that the cache doesn't get bloated with rarely requested information, and it can make an intelligent tradeoff between size and performance.

JSPs are cached individually. That is, if a JSP includes two other JSPs, all three will be cached separately. This means that one component of a page can be cached while the rest are not. Once again...