UML Diagrams MCQs Questions With Answers – Part 31

April 20, 2025 John Howard

Test your knowledge and boost your confidence with these multiple-choice quizzes focused on UML diagrams, foundational software engineering concepts, and real-world best practices. Designed for students, developers, and exam candidates, these MCQs offer a quick and effective way to assess your understanding and sharpen your skills.

1. What does the “opt” fragment model in a sequence diagram?

A An asynchronous call

B An optional condition (if)

C An iteration

D A conditional program termination

The “opt” combined fragment represents a conditional option: the scenario inside the frame only runs if the condition is true. It’s like an “if” without an “else”. Example:

2. What does the “choice” pseudoterminal represent in a state diagram?

A A temporary action

B A decision point with multiple options

C A flow synchronization

D An automatic transition

The “choice” pseudoterminal directs the flow toward different transitions based on conditions. It looks like a diamond, similar to activity diagrams.

3. In a recipe app, each ingredient can be used in multiple recipes. What relationship is this?

A Many-to-many association

B Composition

C Aggregation

D Dependency

An ingredient can appear in multiple recipes, and each recipe contains multiple ingredients → many-to-many. Example:

4. How is a derived attribute written in UML?

A <<derived>> attributeName

B @attributeName

C /attributeName

D ?attributeName

A derived attribute is computed from other data. In UML, it’s shown with a slash: for example, /age may be derived from the date of birth.

5. You want to represent the logical sequence: “Authenticate → Choose action → Execute action”. Which diagram?

A Class diagram

B Activity diagram

C Component diagram

D State diagram

It shows the control flow, perfect for logical step sequences. Example:

6. In a UML activity diagram, how do you model exception handling?

A With a transition to a final state

B With a decision node

C With a handler (exception node) linked to the activity

D With an alt loop

Exceptions are modeled using an exception handler node, generally connected to a specific activity. This handler can catch the error and redirect the flow to an alternative process.

7. In a state diagram, what is a guard?

A A priority transition

B A blocking event

C A logical condition that must be true for the transition to occur

D An action performed during a transition

A guard is a Boolean condition (written in brackets [ ]) that must be true for the transition to happen. Example: [balance > 0] / authorizePayment().

8. You’re developing a medical system. A prescription contains multiple medications, but medications can exist elsewhere. What kind of relationship is this?

A Composition

B Aggregation

C Association

D Dependency

Medications are not deleted if the prescription is removed → aggregation (a weak relationship). Example:

9. What does the “alt” block represent here?

A It’s an exception

B It’s a condition with alternate branches

C It’s an iteration

D It’s a unit test

The “alt” block in a sequence diagram is used to model if/else logic, with alternative scenarios.

10. What does this arrow ..> mean?

A A inherits from B

B B is a subclass of A

C A depends on B (without owning it)

D A contains B

The dashed arrow with an open arrowhead indicates a dependency, often temporary (e.g., parameter, method).

1. What does the “opt” fragment model in a sequence diagram?

2. What does the “choice” pseudoterminal represent in a state diagram?

3. In a recipe app, each ingredient can be used in multiple recipes. What relationship is this?

4. How is a derived attribute written in UML?

5. You want to represent the logical sequence: “Authenticate → Choose action → Execute action”. Which diagram?

6. In a UML activity diagram, how do you model exception handling?

7. In a state diagram, what is a guard?

8. You’re developing a medical system. A prescription contains multiple medications, but medications can exist elsewhere. What kind of relationship is this?

9. What does the “alt” block represent here?

10. What does this arrow ..> mean?

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