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UML Activity Diagram Notation
publish date: 2026/06/09 19:47:9.964611 UTC
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The diagram below shows a simple UML activity diagram.
True or False: In this diagram, Activities B and C execute in sequence - B must finish before C can start.
Correct Answer
False
Explanation
Activities B and C execute in parallel, not in sequence. The solid bar (fork) after Activity A fans out into two arrows leading to both B and C - this means both may execute concurrently. The second solid bar (join) at the bottom requires both B and C to complete before Activity D can begin. This is a fundamental distinction between forks/joins (parallel) and decision diamonds (mutually exclusive alternatives).
Reference
Software Engineering, Ian Sommerville, 10th edition