UML Diagrams for Your Final-Year Project
Your project report has a "System Design" chapter, and it is mostly diagrams. Here is which UML diagrams to include, what each one must show, and how to avoid the mistakes that cost marks in the viva.
Final-year project · 2026-10-14 · 10 min read
The usual set
| Diagram | Answers the question | Must show |
|---|---|---|
| Use case | Who uses the system, and for what? | Actors, use cases, system boundary |
| Class | What are the main objects and how are they related? | Classes, attributes, methods, associations |
| Activity | How does a process flow, including decisions? | Actions, decisions, start/end, swimlanes if several roles |
| Sequence | In what order do objects talk to each other for one feature? | Lifelines, messages, return messages |
| State | How does one object change over its life? | States and the events that move between them |
Most reports also include two non-UML diagrams: a DFD (data flow) and an ER diagram (database). Together these seven cover analysis, design and data.
Use case diagram
Draw the system as a box. Put actors (stick figures) outside it — Student, Admin, Payment gateway — and use cases (ovals) inside — Register, Pay fees, View results. Connect each actor to the use cases it performs. Use «include» for a step that always happens as part of another (Pay fees includes Verify login) and «extend» for an optional one (Apply late fee extends Pay fees).
Example: Use case diagram for an ATM.
Class diagram
Each class is a box with three parts: name, attributes, methods. Show visibility (+ public, − private), types (title: String), and relationships: a plain line for association with multiplicities (1, 0..*), a hollow triangle for inheritance, a filled diamond for composition (the part dies with the whole) and a hollow diamond for aggregation.
Example: Class diagram for a library system.
Activity diagram
Like a flowchart with superpowers: a filled circle to start, rounded rectangles for actions, diamonds for decisions and merges, a bar for parallel work (fork and join), and a bullseye to end. If several roles are involved, split it into swimlanes so it is clear who does what.
Example: Activity diagram for an online exam.
Sequence diagram
Pick one feature — "Student logs in" — and draw each participant as a lifeline across the top: Student, Login page, Server, Database. Arrows going down the page show messages in time order; dashed arrows show replies. Use an alt frame for if/else (valid vs invalid password) and a loop frame for repetition.
State diagram
Choose the one object whose status matters — an Order, an Application, a Ticket — and draw its states (Placed, Paid, Shipped, Delivered, Cancelled) with arrows labelled by the event that causes each change.
Viva questions to prepare
- What is the difference between «include» and «extend»?
- What is the difference between aggregation and composition?
- Why did you choose this multiplicity between these two classes?
- How is an activity diagram different from a flowchart?
- Which diagram shows the timing of messages between objects?
- How does your DFD level 1 balance with level 0?
Tip: Make sure the diagrams agree with each other: every use case should appear as a sequence or activity diagram somewhere, and every class should map to a table in the ER diagram.
Try: class diagram for your project →
Frequently asked questions
Which UML diagrams are required for a final-year project?
Typically use case, class, activity and sequence diagrams, often with a state diagram. Most reports add a DFD and an ER diagram, which are not UML but are expected.
What is the difference between include and extend in a use case diagram?
«include» is a step that always happens as part of the base use case; «extend» is optional behaviour that happens only in some situations.
Can AI generate UML diagrams for my project?
Yes. Describe your project in AI Flowchart and it generates editable use case, class, activity, state and sequence diagrams — or use the Project Kit to get the whole set with explanations and viva questions.