An in-depth exploration of Java sealed classes and their role in enabling exhaustive pattern matching, a feature introduced in Java 17+. The article demonstrates how sealed classes restrict inheritance hierarchies and allow compilers to verify that all cases are handled in pattern matching expressions.
Background
Java 17 introduced sealed classes (JEP 409) as a preview feature, later finalized in Java 17. Combined with pattern matching for instanceof (Java 16) and generalized pattern matching (Java 21), they enable safer and more expressive type hierarchy management.
- Source
- Hacker News (RSS)
- Published
- Oct 18, 2026 at 10:47 PM
- Score
- 7.0 / 10