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Identify the subtle bug in the following Abstract Factory code snippet that creates Victorian furniture:

medium🐞 Bug Identification Q7 of Q15
OOP & Design Patterns - Factory vs Abstract Factory vs Builder - When to Use Each
Identify the subtle bug in the following Abstract Factory code snippet that creates Victorian furniture:
AVictorianChair class missing lie_on() method
Bcreate_sofa() returns VictorianChair instead of VictorianSofa
CVictorianSofa class missing sit_on() method
DFactory class missing abstract base class inheritance
Step-by-Step Solution
Solution:

  1. Step 1: Inspect create_sofa() method

    It incorrectly returns VictorianChair instance instead of VictorianSofa.

  2. Step 2: Trace method calls

    sofa.lie_on() will fail because VictorianChair lacks lie_on() method.

  3. Final Answer:

    Option B → Option B

  4. Quick Check:

    Incorrect product returned breaks Abstract Factory contract [OK]
Quick Trick: Factory must return correct product types [OK]
Common Mistakes:
MISTAKES
  • Overlooking wrong return type
  • Assuming missing methods cause bug
Trap Explanation:
PITFALL
  • Candidates confuse missing methods with wrong returned object type.
Interviewer Note:
CONTEXT
  • Tests bug spotting in Abstract Factory implementation.
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