Core Library 
The core library is the basic framework for the UI element libraries. This core library includes the following elements:
· Layout
In this library, the structure of the UI elements has already been specified, such that the application developers can easily access Web Dynpro concepts and thus quickly recognize, for example, the interaction between the UI element and the layout of the container. Similarly, the library offers application developers a starting point for considering the relationships between classes, such as generalization and aggregation.