[Solved] Considering maintainability, what is a key disadvantage of using abstract classes instead of interfaces in evolving APIs? | OOP & Design Patterns

OOP & Design Patterns - Abstraction - Abstract Class vs Interface - When to Use Which

Considering maintainability, what is a key disadvantage of using abstract classes instead of interfaces in evolving APIs?

AAbstract classes cannot provide default implementations, limiting maintainability.

BInterfaces allow adding new methods without breaking existing implementations; abstract classes do not.

CAbstract classes force all subclasses to recompile when changed, while interfaces do not.

DInterfaces cannot be extended, making them less maintainable than abstract classes.

Step-by-Step Solution

Solution:

Step 1: Understand API evolution constraints
Adding methods to interfaces traditionally breaks existing implementations unless default methods are used.
Step 2: Compare abstract classes and interfaces
Abstract classes can add new concrete methods without breaking subclasses; interfaces historically could not, but modern languages allow default methods.
Step 3: Identify key disadvantage
Abstract classes force recompilation of subclasses when changed; interfaces with default methods allow adding methods more safely.
Final Answer:
Option C -> Option C
Quick Check:
Abstract classes require recompilation of subclasses; interfaces with default methods ease API evolution [OK]

Quick Trick: Abstract classes require subclass recompilation on change [OK]

Common Mistakes:

MISTAKES

Trap Explanation:

PITFALL

Candidates overlook recompilation needs of abstract classes and default methods in interfaces.

Interviewer Note:

CONTEXT

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Considering maintainability, what is a key disadvantage of using abstract classes instead of interfaces in evolving APIs?