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Comment by leapis | Hacker News Reader

Nullable is a huge issue in Java, but annotation-based nullability frameworks are both effective and pervasive in the ecosystem (and almost mandatory, IMO).

I'm really excited about https://jspecify.dev/, which is an effort by Google, Meta, Microsoft, etc to standardize annotations, starting with @Nullable.

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This can never be as effective as changing the default reference type to be not nullable, which would break backwards compatibility, so you can never really relax.

I know Kotlin is basically supposed to be that, it has a lot of other stuff though, and I haven't used it much.

That's basically what c# has done. But it's implemented as a warning which can be upgraded to an error. I think it might even be an error by default in new projects now.

Holy shit, how didn't I know they'd taken it this far? This is great! https://learn.microsoft.com/en-us/dotnet/csharp/nullable-ref...

They actually fixed the billion dollar mistake...

They didn't. A proper fix would require getting rid of null altogether in favor of ADTs or something similar. I work with C# daily and nulls can still slip through the cracks, although it's definitely better than @NotNull and friends.

I haven't worked with Kotlin in a while, but IIRC their non-nullable references actually do include runtime checks, so you cannot simply assign null to a non-nullable and have it pass at runtime like you can (easily) do in C#.

they won’t change the default reference type to non null. might take a few years but you can see their planned syntax here: https://openjdk.org/jeps/401

I hope they succeed. So many people have tried.

Not having nulls is easy.

Persuading Java devs not to use nulls is hard.

I was just writing about nullability annotations!

https://news.ycombinator.com/item?id=37534184

Nullable annotations don’t work with well with generics, or at least those tools I use.

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