Additional Notes
Extending Sealed Classes?
Track: Java
Topic: Language Upgrades
Focus: Sealed Classes
Java: Sealed Classes
Answer
Subclasses must be final, sealed, or non-sealed.
When extending a sealed class, subclasses must be explicitly marked as final, sealed, or non-sealed. This requirement ensures that the class hierarchy remains controlled and transparent. For example, in a sealed class `Order`, the subclass `OnlineOrder` could be final, indicating it cannot be extended further, keeping the hierarchy clear and manageable.
When extending a sealed class, subclasses must be explicitly marked as final, sealed, or non-sealed. This requirement ensures that the class hierarchy remains controlled and transparent. For example, in a sealed class `Order`, the subclass `OnlineOrder` could be final, indicating it cannot be extended further, keeping the hierarchy clear and manageable.
Topics: Java Language Upgrades Sealed Classes