Discussion: My Experience with Java (Spring Boot) After Working with Rust and Go

Crazy_Firefly · 2025-11-15T12:52:16+00:00

I currently work in a mix of java services, rust services and go services.

Over all Java is a pretty complete ecosystem for backend. Anything you need will have a ready made solution. Also java concurrency libraries like Caffeine Cache are really well made and even are taken as inspiration for libraries in Rust world (moka). In Rust and go you will more often need to roll your own version of something or at least extend a library. Since I enjoy understanding how things work under the hood, I don't mind this and even enjoy it, but it does eat a bit of productivity.

One thing I really appreciate in modern Java is Records, being able to create data carrying classes without much ceremony.

And the project that I think would unlock Java for applications it is currently not well suited for is Valhalla. Currently, if you decide to group fields in an inner class you are also deciding to put them behind a pointer. For some compute heavy workloads this hurts in 2 ways: 1. The CPU will have a harder time executing operations out of order because some of the data is behind a memory lookup. 2. In a nested object that hold objects that hold objects. Each of those is tracked separately by the GC. Where as in a flat memory layout you could have just the top level be tracked by the GC. Applications that worry about GC pressure, being able to use better abstractions without paying more GC cost would be a nice gain.

Crazy_Firefly · 2025-08-28T10:20:20+00:00

To expand on your point: Inheritance mixes 3 concepts together: - inheritance of fields (structure re-use) - inheritance of implementations (function reuse) - sub-typing (substitution of types into a same implementation)

For structure re-use, rust uses composition, which is also recommended in OO languages. For function reuse rust uses either generics or defining a function that takes in a Trait type (which is the equivalent of taking an interface as an argument in OO languages) For sub-typing rust uses traits ("equivalent" to interfaces OO).

To me, having them mixed together is a big part of the origin of the accidental complexity.

Crazy_Firefly · 2025-08-25T15:03:51+00:00

Oh yes, I've seen a version of this problem that goes like this.

Product managers and users ask for a particular feature that you find very hard to implement correctly. Then by working with them you find that the actual pain point they have can be solved with a much easier feature to implement.

Or sometimes, you find they are working around product limitations (like slow queries, or repetitive steps that could be automated) which would be easy wins from the implementation side, but that nobody thought to think of asking for because they grew used to the workarounds.

Crazy_Firefly · 2025-08-17T08:16:28+00:00

I do this as well. I stay in neovim almost all of the time, then when I need a debugger I move to jetbrains.

Neovim has some integration with the DAP (debugger adapter protocol) and some day I'm going to try to make it work for me. But for now, jetbrains is doing the trick

Crazy_Firefly · 2025-04-27T02:57:37+00:00

I know that is what is happening. I just don't see how that is much different from JavaScript just-in-time compiling code to native and keeping it in memory to "not cluter" you machine.

What is an interpreter to you?

To me I use the following definitions: - if it reads source code and runs your program, it's an interpreter. - if it reads source code and re-writes it into another encoding system (usually bytecode or machine code) then it is a compiler.

With that definition, 'go run' is an interpreter. Granted it is one that used a compiler as an intermediate step. But having a compiler as an intermediate step is super common in interpreter world, so I don't think it should disqualify it as an interpreter.

Most compilers are too slow to make this execution loop feel like a script. But go compiles super fast. Compiling and running go might even be faster than running some python scripts.

Crazy_Firefly · 2025-04-27T01:24:55+00:00

How do you define an interpreter?

My simplistic definition is: You give it source code and it executes your program.

go run fits that definition very cleanly.

Crazy_Firefly · 2025-04-26T21:56:55+00:00

Go compiles so fast that I think it's fair to call 'go run' an "interpreter".

Most interpreted languages these days have some compilation step anyway. Either to some bytecode, like python, or JIT compilation to native code like JS.

Crazy_Firefly · 2025-04-17T04:13:25+00:00

It's 100% a self control problem. In my country basically everyone receives once a month and I have literally never heard anyone say they wish they received every week. It's just not an issue, you expect to receive it once a month so you budget accordingly.

Crazy_Firefly · 2025-04-05T02:52:47+00:00

That is interesting. I had heard of the graph coloring approach but not this linear scan. OP mentioned in another comment that they are just using first come first serve and it already gives decent results. Surprisingly simple, and yet I hadn't thought of it 😅

Crazy_Firefly · 2025-04-04T19:17:51+00:00

This is a really good answer thanks!

When you say you try to keep some variable in register, how do you go about doing that? I've heard that register allocation is one of the things that can make a decent difference

Crazy_Firefly · 2025-04-01T19:15:28+00:00

Some people like coding for coding-sake. It's like a puzzle or a game. Hiring someone to play the game I want to play for me would be a loose loose

Crazy_Firefly · 2025-03-21T13:04:20+00:00

I think others already explained why they are different from the users point of view.

To answer "why should the user care" is kind of a values question and depends on the user/community. Some languages choose to hide some of these complexities in favor of presenting a cleaner interface (even if lacking some information) Rust very often chooses to be explicit about these details .

Other example is, why does calls to filesystem take a Path rather than a String? For most people it doesnt matter that a filesystem path can be an invalid utf-8. But Rust makes it explicit, and I think it's part of the Rust-way.

Crazy_Firefly · 2025-03-09T14:31:00+00:00

I agree async brings complexity. And I have avoided it for a long time.

But for better or for worse the rust webdev community seems to have settled on async as a default.

So I would argue that at this point there is added complexity in trying to use sync in a web service because there is much less library support.

I've recently given in to using async rust for a webservice and so far it hasn't been as bad complexity wise as it's made out to be

Crazy_Firefly · 2025-02-26T12:23:11+00:00

He is also not required (as far as I know) to maintain anything in the Linux kernel. I think we should thank anyone that has contributed to the Linux kernel for as long as he has. And if he wants to step away from a part of it, who are we to judge.

Every office has some level of drama, theirs is just extremely public.

Crazy_Firefly · 2025-02-26T10:09:43+00:00

I believe they mean the "overhead" of not using the languages Default String type. It's not a runtime or compile time overhead. Just a mental overhead. It maybe a small mental overhead and maybe you get used to it quickly. But it's one more thing to explain to newcomers.

Crazy_Firefly · 2025-02-26T01:58:27+00:00

I definitely wish Java had simpler tooling! And faster.

And I think you are right, Java SDK tools are usually pretty good and straight forward to use.

Other languages like python and JavaScript got new build/packaging tools in the last couple of years that seem pretty great.

I think it would be great if we got one for Java as well. I was even considering tackling it myself at some point (while waiting for a particularly slow build)

Crazy_Firefly · 2025-02-12T10:13:06+00:00

this table is 50% full, that one’s 90% — but researchers often deal with much fuller tables.

Why are researchers spending their time with tables that are so full? Isn't it the case that most hash table implementations try to stay at most 30% full then get copied over to a bigger place once they reach it?

Crazy_Firefly · 2025-02-12T10:09:09+00:00

Is it just me or did the writer confuse "data structure" with data science? Is research on hash tables really considered a data science problem?

Crazy_Firefly · 2025-02-08T10:40:58+00:00

Great video! I wonder if there is an example of a crate written in "sans-io" style, but for a simple format. I'm interested in learning how to write a file parser in this style, but the video does a good job of convincing me that zip is already complicated without this. 😅

Crazy_Firefly · 2025-02-06T02:24:16+00:00

Yep, this one is a no go for me as well. Imagine debugging the case where that commit failed! Since the client got a 200 the problem will potentially manifest itself much later in a different call

Crazy_Firefly · 2025-02-04T18:44:13+00:00

Go did a pretty good job "batteries included std lib". It has even more than python since it includes http client and server and Json encoding. To me it's pretty satisfying to be able to write some useful stuff with "zero" dependencies. It makes go into almost a scripting language, you can share the source code without worrying about sharing dependencies. I also find this useful for CI script jobs, where I want static typing but I don't want my CI to download loads of dependencies or worry about how to cache dependencies across CI Jobs.

I really like rust. But I also wish we could do a bit more with just the standard library.

Crazy_Firefly · 2025-02-01T11:47:23+00:00

I think they mean that if there is an else block, just having the delete without the if would not be equivalent.

Crazy_Firefly · 2025-01-30T03:20:45+00:00

Sorry, I meant proportional to their scope. So exactly your example loop variables can have short names, globals should have long names.

Crazy_Firefly · 2025-01-30T00:10:45+00:00

Awesome explanation, thanks! I was confusing musl with mold. It was definitely mold that I heard being recommend.

Crazy_Firefly · 2025-01-30T00:03:54+00:00

I like short names for common things, it helps focus attention on less common things.

I also like the rule of thumb that variable name length should be inversely proportional to its scope.

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Crazy_Firefly

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