rewrite VS spring-fu

If you're into this sort of thing, there's OpenRewrite[1] for the Java ecosystem.

[1] https://docs.openrewrite.org/

> Spring has gotten so bloated.

I'd call Spring feature-rich than bloated. You can always shed weight that you don't want to carry.

> Plus there's multiple ways of doing the same thing. e.g. JPA, spring-data.

That's because there are different ways to solve a problem. Someone may want an ORM-based approach to connect to the database; they can choose spring-data-jpa. Someone may want to use JDBC with a light abstraction on top of it; they can choose spring-data-jdbc. It's all about choices and right tradeoffs and Spring offers plenty of them.

> they don't provide easy upgrade paths between majors versions

That's not my experience. I've been happily upgrading 2.x.x versions and plan to upgrade to 3.2.x when it is ready. But depending on the codebase, I admit it can be painful. Projects like OpenRewrite[1] might help here.

> and they stop updating vulnerabilities on older major versions.

This is not news. They want you to pay for extended support if you need it.

> No docs on migration.

They do maintain migration docs on GitHub wiki which are a lot more detailed than their blog posts on migration. Here's the latest one to upgrade from Spring Boot 2 to 3: https://github.com/spring-projects/spring-boot/wiki/Spring-B...

[1]: https://github.com/openrewrite/rewrite

The issue you may run into when migrating from Spring Boot 2.x to 3.x is the JEE namespace renames. Migrating code from 8 to 17 in my experience hasn't been all that difficult. In most projects, there are no changes to make. However, with the namespace change, you'll probably have to do some planning and testing. If you are migrating a lot of projects, check out Open Rewrite, it may help automate a lot of these upgrades (for both 8 to 17 and Spring Boot versions).

Couldn't OpenRewrite (https://docs.openrewrite.org) do a big part of this manual work?

Openrewrite would probably be a big help, see https://docs.openrewrite.org

In a similar vein there is OpenRewrite which is an open-source project that works in a similar way. It also has a lot of great refactorings already built in, like doing all the grunt work for migrating to JUnit 5, or replacing string concatenation in SLF4J log calls with parameterized formatting.

seems a case for https://docs.openrewrite.org/

https://github.com/openrewrite/rewrite might help

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.