Additional Notes
What happens if a subclass of a sealed class is not listed in the ‘permits’ clause?
Track: Java
Topic: Language Upgrades
Focus: Sealed Classes
Java: Sealed Classes
Answer
The compiler will generate an error. Frame the concept in practical terms so you can explain it during interview discussion.
If a subclass is not listed in the 'permits' clause of a sealed class, the Java compiler will produce an error. This ensures that only the specified subclasses can extend the sealed class, maintaining the integrity of the design. For example, if `GiftCard` is not in the 'permits' list of `Payment`, any attempt to subclass `Payment` with `GiftCard` will result in a compile-time error.
If a subclass is not listed in the 'permits' clause of a sealed class, the Java compiler will produce an error. This ensures that only the specified subclasses can extend the sealed class, maintaining the integrity of the design. For example, if `GiftCard` is not in the 'permits' list of `Payment`, any attempt to subclass `Payment` with `GiftCard` will result in a compile-time error.
Topics: Java Language Upgrades Sealed Classes