What is a UML Use Case Diagram?

A UML Use Case Diagram is a powerful visual representation that helps depict the functional aspects of a system from a user's perspective. It's like a roadmap that showcases how users or external systems interact with a particular software application.
Key Components of a Use Case Diagram:
Actors:
These are the participants in the system, typically representing users or external entities. Actors are crucial as they initiate and participate in various use cases.
Use Cases:
Use cases are the specific functionalities or actions that the system provides to its users. Each oval in the diagram represents a use case, making it easy to understand the different features offered.
Associations:
The lines connecting actors to use cases illustrate the interactions between them. This visual connection helps in identifying which actors are involved in specific use cases.
System Boundary:
A box delineating the system boundary encloses all the use cases. It clearly defines the scope of the system under consideration.
Why Use UML Use Case Diagrams?
Clarity in Communication:

Use Case Diagrams serve as a common language between developers, designers, and stakeholders. They provide a clear and visual way to communicate the functionalities of a system.
User-Centric Design:
By focusing on how users interact with the system, Use Case Diagrams help in designing software from a user's perspective. This user-centric approach enhances the overall user experience.
Requirements Analysis:
These diagrams aid in the identification and analysis of system requirements. By visually mapping out use cases, development teams can ensure that all necessary functionalities are considered.
Creating an Example Use Case Diagram:
Imagine an online shopping system. The customer is the primary actor, and key use cases include browsing products, adding items to the cart, and the checkout process. Associations between the customer and these use cases illustrate the user's journey through the system