spring-native VS spring-fu

It was probably not a very good idea to write Lambda using Java programming language and Spring Boot Framework. Despite the well-spread usage and knowledge of this framework, the fact that Spring (Boot) heavily uses reflection and takes time to start the embedded Web Application Server led to very big cold starts which we'll explore in the next section. But now with SnapStart on AWS and GraalVM Native Image Support we have two more options how to optimize those cold starts. So let's explore how to write Lambda function using the Spring Boot. The code of this sample application (the same as for the first 3 parts but rewritten to use Spring Boot) can be found here. It provides AWS API Gateway and 2 Lambda functions: "CreateProduct" and "GetProductById". The products are stored in the Amazon DynamoDB. We'll use AWS Serverless Application Model (AWS SAM) for the infrastructure as a code.

During this experience, I was surprised to find that Spring Native doesn't support caching yet. I believe this support will be added by the community soon. In the meantime, if you're looking to start/stop your infra as fast as possible, you probably don't care about caching. Caching is made for long-lived, JVM-strong, JVM-loving apps.

fuente: https://spring.io/blog/2021/03/11/announcing-spring-native-beta

As I just found out thanks to a comment from another Redditor, spring-aot will be getting some functional configuration compile time generation support in Spring Native's next release

Not sure how far they are currently, but have you heard of Spring Native? https://spring.io/blog/2021/03/11/announcing-spring-native-beta

I have to say Spring. Because it is so mature and well-documented. Sure, it is bloated sometimes and not very well-suited for small JAR packages. And I have tried other frameworks as well, but I find that I keep returning to Spring. Especially since Spring keeps adding features that caused competing framework to have an edge over Spring, like native images with Spring Native for example.

Our next steps are : provide great Kotlin/JVM/Native (Native with Kotlin JVM via GraalVM native images) support via https://github.com/spring-projects-experimental/spring-native/, empowering multiplatform development (with Kotlin/JS frontend for example), translating Spring Boot documentation to Kotlin (via a contribution from Kotlin team), make sure that some APIs like WebTestClient currently broken with Kotlin due to some type inference bugs with recursive generic types become usable.

I doubt micronaut has better runtime performance. You're probably talking about startup time and this point is moot with either https://github.com/dsyer/spring-boot-auto-reflect Or https://spring.io/blog/2021/03/11/announcing-spring-native-beta

The point isn't that one should reinvent the way that Tomcat is started, but that Spring Boot (by default) is using action at a distance and runtime reflection which have serious downsides if you want to understand what's actually going on because you're a) new to the technology, or b) have to debug some weird edge case.

The alternative is using explicit, reflection-less code - which you can do even with Spring, although it's experimental: https://github.com/spring-projects-experimental/spring-fu

Bean Definition -> Still needed although experimental projects like Spring Fu might remove their need in the future. Technically, there is nothing to stop you from registering beans functionally right now but the verbosity is likely to make that approach less optimal.

Most of these things can be done with higher-order functions too.

I think that if Java had had lambdas earlier, Spring and other such frameworks might look very different. You can see that already, Spring is adding (experimental?) support for more declarative styles of configuration instead of the rather slow and hard-to-debug reflection magic: https://github.com/spring-projects-experimental/spring-fu

Quarkus just moves the problem IMHO. I find it similarly convoluted to use as normal Spring. I had to deal with that a few months ago on a project. Honestly, it actually feels a lot like spring used to be; and not in a good way. Lots of annotation magic all over the place.

I use Spring Boot by default. But I aggressively limit the use of annotation magic. I've never liked the byte code hacks people do to make annotations inject magical behavior. Hard to debug and painful when it does not work as expected.

I don't think either of these frameworks have an edge over each other. You end up using a lot of the same underlying library ecosystem.

I do like the annotation less direction that Spring has been taking since they started adding Kotlin support 4-5 years ago. If you want to, you can get rid of most annotations for things like dependency injection, defining controllers, transactions etc.

Especially with Kotlin, this makes a lot of sense. With Java, dealing with builders is just a lot more painful without kotlin's DSL support. You basically end up with a lot of verbosity, method chaining, etc. But it's possible if you want to. It's a big reason, I prefer using Kotlin with Spring Boot. Makes the whole thing feel like a modern framework. The hard part with Spring Boot is being able to tell apart all the legacy and backwards compatible stuff from the actual current and proper way of doing things.

There's a project that they've been pushing to get rid of all annotations: https://github.com/spring-projects-experimental/spring-fu/tr.... I suspect a lot of that stuff might be part of spring boot 3.x later this year. And quite a bit of it is actually already part of the current version of Spring.

This makes spring boot very similar to what you'd do with ktor. All you do is call kotlin functions. No annotations. No reflection. No magic. Very little verbosity. It's all declarative. And a nice side effect is also that it makes things like spring-native easier, which they started supporting recently.

It's very similar to using ktor with koin (for dependency injection). That combination is worth a try if you are looking for something lightweight and easy to use. Spring Boot has more features and complexity but it can be as simple to use as that if you know what you are doing.

Mostly, keeping things simple is a good thing with Spring. Also, I don't tend to do everything the spring way. Spring integration is a bit of a double edged sword for example. It offers a subset of the features of the libraries that it integrates. If you want the full feature set, you end up working around that. IMHO, you should do that by default. I've removed spring integration from several projects.

> And that is a problem how? Stick to one style.

Switching an API from "a result or nothing" to "a result or an error message" happens all the time, and switching in the other direction is only slightly less frequent. And of course most programs have some APIs where one is appropriate and some where the other is. So consistency is valuable.

> https://github.com/spring-projects-experimental/spring-fu/tr...

Still reflection-based.

> There's nothing magical about it.

It's magical to anyone thinking in the language - it breaks the rules of the language, so you can't reason about what it does.

SpringFu (from Spring team): https://github.com/spring-projects-experimental/spring-fu/tree/main/jafu

It's mentioned in the article, even though the examples are written in Kotlin spring-fu supports a java-based dsl.

It's possible to remove it anyway, provided you accept to use APIs considered experimental. The solution is Spring Fu, with "Fu" standing for functional. It's available in two flavors, one for Java and one for Kotlin, respectively named JaFu and KoFu.

There is already a very close collaboration between Kotlin and Spring teams. I think leveraging more multiplatform capabilities and more DSL à la KoFu from https://github.com/spring-projects-experimental/spring-fu could increase Koltin usage on server side long term.

There's a next stage after annotations. The current thinking is to replace annotations with function calls. It makes more sense if you use Kotlin because Java is a bit verbose when you do this and in Kotlin you get to create nice DSLs. This cuts down on use of reflection and AOP magic that spring relies on and also enables native compilation. It also makes it easier to debug and it makes it much easier to understand what is going on at the price of surprisingly little verbosity. Kofu and Jafu are basically still experimental but work quite nicely https://github.com/spring-projects-experimental/spring-fu/tr...

Another trend is native compilation. Spring native just went into beta (uses the Graal compiler). That still relies on reflection but they re-engineered the internals to be more native friendly.

Spring Boot basically added the notion of autoconfiguring libraries that simply by being on the classpath self configure in a sane way. It's one of those things that makes the experience a bit more ruby on rails like. Stuff just works with minimal coding and you customise it as needed (or not, which is perfectly valid).

Compared to XML configuration, Spring has come a long way. Separating code and configuration is still a good idea with Spring but indeed not strictly enforced. @Configuration classes can take the place of XML and if you use the bean dsl, that's basically the equivalent of using XML. Only it's type checked at compile time and a bit more readable.