What step are we talking about? Javac itself is absolutely on the same order of magnitude speed as Go per loc, while rust is significantly slower (which makes sense, the latter is a properly optimizing compiler with heavy static analysis, while the former two just spews out java byte code/machine code).
Gradle with a daemon is also pretty fast, you are just probably used to some complex project with hundreds of dependencies and compare it to a cargo file with a single dependency.
Just a nitpick, but the static analysis in Rust doesn’t account for most of why compilation is slow, as proven by the fact that cargo check is much faster than cargo build.
Yeah, I know. I believe it’s mostly the amount of LLVM IR that is the problem (e.g. each generic instantiation outputs by default a new copy of roughly the same code), isn’t it?
> Javac itself is absolutely on the same order of magnitude speed as Go per loc
Not really when it has to run on a cold JVM. And before it warms up, it’s already done.
Then you are in territory of keeping the compiler process between the runs, but that is a memory hog and also not always realiable (gradle often decides to run a fresh daemon for whatever reason).
So theoretically, in lab conditions yes, in practice no.
> while rust is significantly slower
Everybody repeats that but there is surprisingly little evidence in form of benchmarks. I can see rustic compiles over 50k Loc per second on average on my M2, which is roughly the same order of magnitude as Java. And checking without building is faster.
I've yet to see a project where Gradle daemon a) does anything useful and b) is acutally used by gradle itself (instead of seemingly doing everything from scratch, no idea what it does in the seconds it takes for it to start up).
>I've yet to see a project where Gradle daemon a) does anything useful
Also my experience.
Only using Gradle deamon does not help making a multi-project setup much faster. You also have to enable build cache, configuration cache and configure on demand with `--configuration-cache --configure-on-demand` and hope nobody in the project breaks the ability for Gradle to use these caches. But then it still took at least 10 seconds to build and start my services (and that's with incremental builds, like you changed one line of code after the first slow build). I spend two days and more after release to speed this stuff up, before it was 30 seconds sometimes 60 seconds.
And the protobuf Gradle plugin sometimes did not update the generated code, so you had force-delete the files on every build. And then other stuff in the caches broke and you had to delete `.gradle` directory and sometimes even the `~/.gradle` directory. And sometimes the Gralde daemon hangs so you have to force it to stop with `--stop.
Go build, deno and bun are so much more reliable and faster. Something that was surprisingly fast was using the Gradle setup with skaffolding. Java hot code swapping is very fast.
This. Gradle wastes tremendous amounts of time on non-compile tasks. So even if Java takes a few seconds to compile, the whole build is often much, much longer. Interestingly, my impression is that maven is significantly more snappy.
> gradle is faster as a build tool for incremental compilation
Implicit:
> …than it is building from scratch, where it needs to download lots of stuff
I mean, yes, saying Java builds are fast does seem a bit “rolls eyes, yes technically by loc when the compiler is actually running” …but, ^_^! let’s not start banging on about how great cargo/rust compile times are… they’re really terrible once procedural macros are used, or sys dependencies invoke some heinous c dependency build like autoconf and lots of crates do… and there’s still a subpar incremental compilation story.
So, you know. Eh. Live and let live. Gradle isn’t that bad.
So maybe I was just unlucky with gradle and lucky with cargo. A project that is a mixture of 20k LoC Scala and 300k LoC Java took 6 minutes to compile, and incremental was still several tens of seconds. Cargo/Rust cold compiles a project of 1M LoC (all dependencies) in about 1:30 on the same hardware and incremental is like 2-4 seconds.
As for precedural macros - yes they can be slow to compile but so are Java annotation processors.
Scala is a much different case, it has one of the most advanced type systems, many implicit scoping rules etc. Even a java change that might affect the scala codebase could result in a slow incremental build. Also, the build system may not have been as modular as it could.
In my experience, java annotations gets processed very fast.
Well, that's a bit of a stretch. It is definitely one of the most complex type systems due to interactions between nominal sub-typing and type classes which is a bit hairy. But in terms of what this type system can express or prove, it's both inferior (cannot express lifetimes or exclusive access) and superior (HKTs, path dependent types) to Rust in some aspects. Let's say they are close.
Scala is the problem here. Scala has several issues filed for slow compilation.
300K LOC Java should be done within ~1.5 minutes flat from zero. Can be even faster if you are running maven daemon for example. Or even within ~30 seconds if everything is within one module and javac is only invoked once.
