I've been a fan of the "newtype" pattern for a while, especially as it applies in Rust. I'm really interested in applying this in my Java projects to avoid using generic types like `String` or `int` everywhere. I've been hesitant because I thought there would be significant runtime overhead, particularly from wrapping every ID string in our codebase. However, with the proposed value classes from the JEP 401, I wonder if I could implement this pattern without impacting performance. Will using value records like `value record FooID(String);` and `value record BarID(String);` be just as efficient as using plain strings? Should I reconsider using regular records or even traditional classes instead? I've always thought that wrapping each ID would add excessive heap allocations, but I'm not sure if that's the case. I'd love to hear your experiences and thoughts on this!
2 Answers
Value classes are definitely what you need! They can act as lightweight wrappers around your existing types with far fewer allocations and better optimization opportunities. Going forward, this should be the way to type safety in Java!
You are right to consider performance! But remember, only a few allocations can impact performance noticeably. If IDs are created and used temporarily, the impact of those wrappers might be negligible due to escape analysis optimizations in the JVM. Benchmarks are essential!
Exactly! You might find that the overhead is much less than you think. Just make sure to test it in your specific case.
Yes! Java needs to embrace these patterns more for safer APIs. Plus, the potential for cleaner semantics is just a bonus.