Sealed Classes #java

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Across
  1. 2. — Can appear in a permits clause; these classes are implicitly final.
  2. 3. — java.lang.Class methods related to sealing: isSealed() and permittedSubclasses().
  3. 7. — Permitted subclass modifier that allows further extension by unknown subclasses.
  4. 8. — Permitted subclass modifier meaning it cannot be extended further.
Down
  1. 1. — Reference conversion whose compile-time checks are enhanced by sealed hierarchies to rule out disjoint types.
  2. 4. — Modifier that restricts which classes or interfaces may extend/implement a type.
  3. 5. — Clause listing the specific subclasses or subinterfaces allowed to extend/implement a sealed type.
  4. 6. — For named modules, sealed types and all their permitted subclasses must be in the same one.