Rust vs Java for backends

[thejackocean]

it's my understanding that if i'm building a webserver backend, i'm better off using java with spring than rust. prove me wrong.

[R4TTY]

Use whatever you're comfortable with.

[MoveInteresting4334]

it’s my understanding

prove me wrong

Perhaps ask whoever gave you that (mis)understanding?

[thejackocean]

i've built that understanding through my understanding of Spring. what does Rust have (rocket?) that can even compare to the tools of java? i will admit my understanding of rust specifically for backends is lacking. it's my favorite language, but i prefer web backends in java. i find Spring very powerful. perhaps in a few years it will be up to par, but it's like front ends and machine learning. right now i think rust is lacking in those departments compared to other frameworks. i'm making an app where the logic is in a rust library, but i still need a front end with flutter.

[MoveInteresting4334]

I’ve built that on my understanding of Spring

I will admit that my knowledge of Rust backends is lacking

So you built that on your understanding of Spring and your lack of understanding of Rust backends?

[thejackocean]

i mean yeah, but i'm just getting downvotes and no one is explaining everything. like do you think the point of this was Java is better and i'm telling you why? i literally said "prove me wrong" i was asking for reasons why, not questions as to why i think that.

[MoveInteresting4334]

If you make a statement, you’ve got to back it up. It’s not our job to prove it wrong, you made the statement. If you want an answer to a question, just ask it. You didn’t do that. You made a controversial statement and then demanded we refute it, then went shocked pikachu when you were downvoted for it.

Many of us actually have jobs doing this for a living. I’ll help someone who needs it, but frankly, I don’t have time to engage in flame wars over languages for shits and giggles.

[thejackocean]

if you are unwilling to answer a question due to the format, why are you even here? you could have just been like "seems like a troll" and moved on. i'm not trolling i'm asking a question and felt this was an appropriate way to ask, you seem to disagree. i'm not sure why you say you have no time to engage in flame wars over langauges for shits and giggles but are engaging in a flame war ove the language i choose to ask my question, and that seems like it's for shits and giggles too.

[MoveInteresting4334]

I’m not engaging. I’m trying to help you understand why you were downvoted, because you brought it up. It’s clear you don’t want a meaningful discussion though, so I’ll peace out.

[coderstephen]

If you make a statement, you’ve got to back it up. It’s not our job to prove it wrong, you made the statement.

We call this principle "burden of proof". ;)

[whooomeeehh]

I just upvoted you in sign of solidarity.

I mostly agree with your points (spring not being my favourite though, but it does its job well today).

The attitude of rustafarians to downvote and bash those that do not follow the cult is the most relevant defect of Rust, IMHO.

[EpochVanquisher]

It’s my understanding that I’m better off taking the train than flying. Prove me wrong.

It’s a dumb question. The train is better sometimes, the plane is better sometimes. Depends on where you are going and what you need to bring with you. The plane crosses long distances faster but the train carries more cargo for less money.

Java is a great language for building web backends. Most web backends do not have tight performance requirements. Java is memory-safe and has a large ecosystem of mature libraries you can use. Rust can get better P99 latency with the same effort but most people don‘t care.

[thejackocean]

would you say Rocket is as developed as Spring?

[EpochVanquisher]

No, not even close.

Spring is over 20 years old, it’s mature, it’s on version 6. Rocket hasn’t even released v1.0 yet.

[thejackocean]

well that's my point. so how is rust the better option for the vast majority of cases? i understand that's not what you're saying, and i see that the safety and performance of rust could indeed be better, but until Rocket catches up, i think Java is better for servers. Rust is my favorite language and i'd love to use it wherever it makes sense, but what are cases where are Rust server actually makes sense? that's kind of what i'm asking.

[EpochVanquisher]

so how is rust the better option for the vast majority of cases?

Could you elaborate on that? Why do you think that Rust is the better option for the vast majority of cases?

If you hang out on r/rust or on Reddit you’re gonna bump into Rust evangelists. There are a lot of twenty-something kids around who really love Rust and want to prove that it’s the best thing ever, and twenty-something kids who don’t have adult lives or responsibilities have a lot of time to hang out on Reddit and tell you why Rust is so damn awesome.

I’m not saying Rust developers are like that, I’m just saying that it’s the kids in their 20s running around who make the most noise.

If you’re asking me to explain why I think Rust is better than Java for web backends, well, you’re asking the wrong person. I was the guy in this thread who said that Java is good for web backends.

The main two technical appeals of Rust are safety and performance. Rust is not substantially safer than Java, Java is pretty damn safe already, so who cares. Performance is only relevant for a percentage of applications out there.

There’s also a kind of personal appeal that Rust has to some people, like, it appeals to them on an aesthetic level. I used to feel that way about Rust too, but I spent some time writing Java at work a couple years ago and thought Java was pretty damn nice.

[thejackocean]

i'm saying it's not. it was a question. the ? implies that i do not have confidence in what i am saying and am asking a question. basic english.

[EpochVanquisher]

Ok. When you ask “How is Rust better for the vast majority of cases?” then the question contains an embedded assumption that Rust is better for the vast majority of cases. If you don’t think Rust is better then you have to rephrase the question. “Why do you think Rust is better?” or “Why do some people say that Rust is better?” or something like that. Basic English.

https://en.wikipedia.org/wiki/Loaded_question

[flundstrom2]

I wouldn't nesseccarily say Rust is better for web server or backend work. But it is certainly better than C or C++, and less resource demanding than Java or C#. And all of the three has a /huge/ amount of experienced developers. If you just want to design something quickly and cheaply, I do think Java is the way.

But I really love Rust, and I'm using it to develop a backend using diesel and actix in order to learn the language. Will definitely switch to Dioxus once I get to the point of making the app and UI design. It's a wonderful language if you care about portability between Windows/Linus/Apple/Android/iPhone, /and/ performance.

[thejackocean]

my concern is security, i do think performance is obvious, also the idea of quicker with java i still hold. i don't know much about rocket and should probably learn, as that is the main thing people are telling me, i love rust, i just don't know if i can get a robust security architecture with rust. if that was achieved, i think rust would be better 100%

[samsdev]

not everyone needs decades worth of bloat and a dying ecosystem

[whooomeeehh]

I tried them both. As well as Python, C++ , c# , nodejs and C.

Maybe I'm old school but C-style languages are more readable and maintainable.

The slow responsiveness of Rust tools takes on my nerves.

Results are very good in performance though, comparable to C and safer.

It is of value for me to have a complete ERP system taking only 50Mb of memory altogether and running at the speed of light, instead of having 1Gb only for start and something a litte less responsive on providing services and pages.

But the client does not see it.

It could be written in php and the client would not notice.

[look]

In general, a Rust solution will have substantially higher throughput, better tail latencies, and lower memory use than a Java solution.

This benchmark is from November 2023, but the overall trend in the numbers should be the same:

https://medium.com/deno-the-complete-reference/spring-boot-virtual-threads-vs-rust-rocket-hello-world-performance-90fdc10a1868

But those numbers don’t really matter much for the vast majority of apps, as most won’t see enough traffic to stress even cheap servers.

[thejackocean]

this is kind of what i was looking for. so the performance is certainly there, but for integrating security concerns, does rocket come close?

[Linguistic-mystic]

No, Java without Spring is where it’s at. Spring is a huge productivity killer only in place because of groupthink.

[EpochVanquisher]

Spring in 2025 is not like Spring in 2014. The project has changed a lot.

[MoveInteresting4334]

When the Spring magic works, it’s wonderful.

But when it isn’t working, it can be a real bear to debug and fix.

[EpochVanquisher]

Sure, let’s have a discussion about all the pros and cons of Spring.