What is `sealed` interface combined with `non-sealed` permitted subtype in Java 17+?

Explanation

The correct answer is A) non-sealed breaks the seal, allowing that subtype to be extended by any class, mixing sealed hierarchy control with open extension at chosen points. This combination allows for flexibility in the sealed hierarchy while maintaining control over specific subtypes.

Key points

`sealed` interface controls which classes can be subtypes
`non-sealed` allows specific subtypes to be extended by any class
This combination balances hierarchy control with open extension

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