What UML diagram types are available?+
Class (showing classes, attributes, methods, relationships), Sequence (showing object interactions over time), Use Case (actor-system interactions), Activity (flowcharts with decision points), State Machine (state transitions), and Component (system architecture).
What is the difference between association and aggregation in class diagrams?+
Association: two classes are related but independent. Aggregation (hollow diamond): one class contains others but they can exist independently. Composition (filled diamond): one class owns the others - they cannot exist without the parent.
What is PlantUML?+
PlantUML is a text-based diagramming language where you write diagram descriptions in a simple syntax and the tool renders them as images. It's popular for documenting code in comments, README files, and Confluence pages.
What is a sequence diagram used for?+
Sequence diagrams show how objects interact in a particular sequence over time - ideal for documenting API flows, authentication sequences, and microservice communication. Each vertical lifeline represents an actor or system component.