[Solved] In a parking lot system, a developer implements the Vehicle class hierarchy but overrides the equals() method only in the... What subtle bug might this cause when comparing different vehicle types? | OOP & Design Patterns

OOP & Design Patterns - Design a Parking Lot - LLD with OOP (Classes, Patterns, Extensibility)

In a parking lot system, a developer implements the Vehicle class hierarchy but overrides the equals() method only in the base Vehicle class. What subtle bug might this cause when comparing different vehicle types?

ADifferent vehicle types may be considered equal if only base class fields are compared

Bequals() method will throw a runtime exception for subclasses

CPolymorphism ensures correct equals() behavior automatically

DComparisons will always return false due to type mismatch

Step-by-Step Solution

Solution:

Step 1: Understand equals() override implications
Overriding equals() only in base class compares base fields, ignoring subclass-specific fields.
Step 2: Analyze comparison results
Different vehicle types with same base fields may be incorrectly considered equal.
Step 3: Evaluate other options
equals() does not throw exceptions (B); polymorphism does not fix equals() logic automatically (C); comparisons won't always be false (A).
Final Answer:
Option A -> Option A
Quick Check:
Base equals() ignores subclass fields causing equality bugs [OK]

Quick Trick: Base equals() ignores subclass fields causing equality bugs [OK]

Common Mistakes:

MISTAKES

Assuming polymorphism fixes equals() automatically
Expecting exceptions from equals() override
Thinking comparisons always fail due to type

Trap Explanation:

PITFALL

Candidates overlook that equals() must be carefully overridden in subclasses to avoid incorrect equality.

Interviewer Note:

CONTEXT

Tests subtle OOP pitfalls in method overriding and equality.

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More OOP & Design Patterns Quizzes

What subtle bug might this cause when comparing different vehicle types?

Step 1: Understand equals() override implications

Step 2: Analyze comparison results

Step 3: Evaluate other options

Final Answer:

Quick Check:

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