First of all, of course Rust hast some additional complexity because it is close to bare metal. But if you think this complexity away (to make it comparable to e.g. javascript), here are some reasons:
1) Better type-inference. In Java this has improved but is still much more clunky and boilerplatey. Good type-inference is important to not annoy the user.
2) Traits / type-classes. They enable a way of programming that comes much closer to duck-typing and avoid wrapping your objects in wrapper-classes to support interfaces like you are forced to do it in Java.
3) Better and less noisy error handling (looking at you Java, Go, C++ and most other languages)
You can't 'think away' the additional complexity of lifetimes and the borrow checker though. It's something you have to understand and keep in mind.
> Better type-inference. In Java this has improved but is still much more clunky and boilerplatey. Good type-inference is important to not annoy the user.
In my opinion, Java without type inference is fine - it's very minor issue, and there is a fairly limited scope of code that would actually benefit from type inference in terms of quality/readability. If you use a decent editor most of the redundant typing is auto-completed anyway.
> Traits / type-classes. They enable a way of programming that comes much closer to duck-typing and avoid wrapping your objects in wrapper-classes to support interfaces like you are forced to do it in Java.
Eh, Rust traits are better than Java's interfaces, but you can implement multiple interfaces for your own objects in Java without any wrappers. The issue is extending external objects to support new interfaces. Plus, the point is to have correct code defined and checked at interface/trait boundaries, something JS doesn't do at all.
> Better and less noisy error handling (looking at you Java, Go, C++ and most other languages)
The error messages for Rust can be much more complex than Java, and are probably more complex on average, simply because it's a more complex language and type system.
I would say the benefits of Java's type system far outweigh the imperfections and tiny costs when compared to a language like JS.
> You can't 'think away' the additional complexity of lifetimes and the borrow checker though
Of course you can't. But the problem of lifetimes does not go away, not matter if you use statical or dynamic typing. However, in javascript this problem does not exist, so obviously that can't be compared to Rust. If you use Rust, then because you _need_ this for performance.
> In my opinion, Java without type inference is fine
Fair enough, but most people see that very different, hence the unhappiness.
> Eh, Rust traits are better than Java's interfaces, but you can implement multiple interfaces for your own objects in Java without any wrappers. The issue is extending external objects to support new interfaces.
That's exactly what I said or at least meant. :)
> The error messages for Rust can be much more complex than Java
No no, not the error messages that the rust compiler gives you. I'm talking about error handling that the developer does.
> I would say the benefits of Java's type system far outweigh the imperfections and tiny costs when compared to a language like JS.
I agree, but just because the benefits outweight the problems, that doesn't mean people will be frustrated by these problematic parts. And let's not call it imperfections. Java is _so_ far away from perfection, that just gives your post a sarcastic touch.
> However, in javascript this problem does not exist, so obviously that can't be compared to Rust.
Static typing and a whole bunch of other things don't exist in JS as well. The point of a comparison is to highlight the differences and similarities. You were the one who said Rust is more similar to JS than Java, you can't just reduce the language to 'type inference and traits' - things JS doesn't have at all and say it's somehow similar to JS.
> Fair enough, but most people see that very different, hence the unhappiness.
You have data supporting this 'most people see it...' argument? Or you just made it up on the spot?
> No no, not the error messages that the rust compiler gives you. I'm talking about error handling that the developer does.
Error handling in Java is very straight forward and it's far more similar to JS than Rust is.
> And let's not call it imperfections. Java is _so_ far away from perfection, that just gives your post a sarcastic touch.
Java is a great language. It's not overly complex, it's fast, it has great tooling and IDE support, it has one of the largest library ecosystems. It has a huge developer community, many high profile projects, many high profile companies use it. It's easy to find decent Java developers for your project. It has a decent type system - far better than JS or python. From a pragmatic point of view Java is one of the best languages in existence.
1) Better type-inference. In Java this has improved but is still much more clunky and boilerplatey. Good type-inference is important to not annoy the user.
2) Traits / type-classes. They enable a way of programming that comes much closer to duck-typing and avoid wrapping your objects in wrapper-classes to support interfaces like you are forced to do it in Java.
3) Better and less noisy error handling (looking at you Java, Go, C++ and most other languages)