Java Records, Pattern Matching, and Sealed Classes: Modern Java Features

Modern Java (16+) has significantly reduced boilerplate while increasing type safety through three key features:

Records auto-generate constructors, getters, equals(), hashCode(), and toString() from a compact declaration. They're ideal for DTOs, value objects, and domain events. Custom validation via compact constructors allows normalization and constraint checking.

Sealed classes and interfaces restrict which classes can implement/extend them. Combined with records, they enable precise algebraic data types — think PHP enums, but with fields per variant.

Pattern Matching for switch (stable in Java 21) makes working with sealed types elegant. The compiler verifies exhaustiveness at compile time — if all permitted subtypes are covered, no default case is needed. Adding a new permitted type causes a compile error in all switch statements that don't handle it, eliminating an entire class of runtime bugs.

For PHP developers: Records ≈ readonly classes, Sealed Interfaces ≈ backed enums with data, pattern matching switch ≈ match expression. The main advantage in Java is compile-time verification of exhaustive case handling.