Interface Classes and `implements`: Pitfalls

Pitfalls and red flags

• Confusing `interface class` with RTL `interface`; they solve different problems.

• Declaring `implements` but forgetting one required method implementation.

• Trying to store mutable instance state inside an interface class rather than in implementing classes.

• Using interface classes where shared implementation is needed; that belongs in a concrete/virtual helper class.

Related topics

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