Webdynpro ABAP is a standard UI technology for developing web applications in the ABAP environment. It uses an MVC architecture with models to fetch data, views to display the UI, and controllers to connect models and views. The main differences between ABAP Webdynpro and Java Webdynpro are that ABAP Webdynpro uses ABAP coding to access data directly while Java Webdynpro uses RFCs or web services, and the ABAP code is stored centrally on the server. Webdynpro applications are composed of components, views, and contexts to transport data. Navigation between views is established through links and plugs.