This material introduces Unified Modelling Language (UML) as a graphical tool for software system design and communication, highlighting the class diagram as a frequently used type for outlining classes and their relationships. It then transitions to software design principles, including SOLID, emphasizing concepts like separation of concerns and avoiding repetition, while noting these are guidelines rather than strict rules. Finally, the text introduces the Spring Framework, an enterprise Java platform, covering its core features like Dependency Injection and Data Access Objects, and explains how to handle web requests and perform testing using Spring Boot and MockMvc.