Strategy Pattern 2.0: How Modern Java (21-25) Makes the Strategy Pattern Actually Fun to Write

Classic Strategy Pattern tutorials often feel verbose. Modern Java changes that with language features that improve expressiveness and safety.

What changed

Sealed interfaces constrain valid strategy implementations. Records reduce data-carrier noise. Pattern matching supports cleaner decision flow when strategy families share structured inputs.

Practical benefit

You can implement strategy selection with less ceremony, stronger compile-time guarantees, and easier testing. This is especially useful in pricing engines, routing logic, and policy-based rule systems.

Design advice

Prefer composition and explicit capability boundaries. Keep strategy contracts narrow and deterministic. Modern Java gives you tools to write this pattern elegantly without overengineering.