Sakai is built on top of numerous third-party open source libraries and frameworks. Why write code for converting from XML text files to Java objects or connecting and managing databases, when others have specialized and thought out the technical problems and found appropriate and consistent solutions? This reuse of code saves effort and decreases the complexity of creating new functionality. Using third-party frameworks has other benefits as well; you can choose the best from a series of external libraries, increasing the quality of your own product. The external frameworks have their own communities who test them actively. Outsourcing generic requirements, such as the rudiments of generating indexes for searching, allows the Sakai community to concentrate on higher-level goals, such as building new tools.
For developers, also for course instructors and system administrators, it is useful background to know, roughly, what the underlying frameworks...