Enums on steroids - let's look at sealed classes ! by Marcin Chrost

Explore Java's sealed classes with pattern matching and switch expressions. Learn about type-safe hierarchies, records, and improved syntax for handling variants.

Key takeaways

Sealed classes and interfaces allow restricting which classes can inherit/implement them, providing better type safety than enums
Pattern matching with switch expressions in Java provides cleaner syntax compared to traditional if-else chains when handling different types
Records in Java offer concise immutable data classes with built-in constructors and accessors, similar to Lombok’s @Value
Guarded patterns allow additional conditions in switch cases while maintaining exhaustiveness checking
Arrow labels in switch expressions improve readability and reduce boilerplate compared to traditional switch statements
When using records in switch expressions, you can deconstruct record members directly without explicit getter calls
Preview features in Java go through testing periods before becoming permanent, requiring explicit opt-in during preview phase
Sealed hierarchies provide compile-time verification that all possible subtypes are handled
Switch expressions with sealed types eliminate need for default cases since compiler knows all possible variants
Local variables in switch branches have their own lexical scope, preventing accidental variable leakage

Enums on steroids - let's look at sealed classes ! by Marcin Chrost

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