A Web Dynpro Application is an entry point into a Web Dynpro Component and is the only Web Dynpro entity that can be addressed via a URL.There is often (but not always) a one to one relationship between an interface view and an application.In the same way that the functionality in an ABAP module pool can be accessed by defining multiple transaction codes, so the functionality of a single Web Dynpro component can be accessed by defining multiple applications.

Application definitionIn order to define a Web Dynpro application, you must specify The component to be invoked. This component is then known as the “root” component, Which interface view of the root component will be used as the initial view assembly, Which inbound plug will act as the entry point for the nominated interface view (this inbound plug must have the Startup check box selected)