Design Document   Diagram of Architecture   Description of Interaction between Tiers The interaction between persistence tier and business tier has been implemented by implementing class for every object, and their respective EJB class, as can be seen from the Class Diagram. The class of every object has elements and fields inherited from the Product class, which are properties of the object. The EJB of their respective class has been implemented with the create, find, delete and merge operations. The interaction between presentation layer and business layer has been implemented by making the interfaces we based, using JSF pages on xhtml. The information related to product, customer or rentals can be retrieved using the web pages. The entities can be called and database queries has been implemented for the interaction of presentation layer with other two layers.   Description of Page Navigation The pages are made to navigate with following options: 1. The main page has options to: i. create product entry ii. stock of product iii. search for a product iv. create a new customer v. list customers vi. search customers vii. create new orders viii. list orders ix. search orders 2. Selecting any of the options above navigates the browser to the respective page. 3. Every page has options to navigate to main page. 4. The creation page has option of navigation to stock page. 5. Stock page has option to navigate to creation page.