Comment by koito17
Have people considered frameworks implementing JAX-RS instead? Or does the breakage happen specifically in extensions to Spring?
The only inconvenience I have experienced upgrading a Quarkus backend is renaming javax.* package imports to jakarta.*. Hopefully the next major version requires just as little effort (if not less).
I am sure there would have been a lot more work if the project used extensions like the Kubernetes client. But overall, I have had the best experience with tools like Maven (for Java) and Leiningen (for Clojure). It helps to avoid libraries that hack or access JDK internals (e.g. Lombok, or ancient libraries using sun.* internal packages for reflection)
The main problem is Spring Boot and some other Spring projects like Security.
If you would use Spring MVC directly, it is very possible that one could upgrade Spring versions for many years with minimal or no changes at all.
However Spring Boot regularly breaks code. And given the fact that it's very popular, it means that any Java upgrade is pain. You need to rewrite code, sometimes a lot of code.
If you just use JAX-RS, probably simple Spring setup would suffice, but people usually want to slap database, security stuff and other things and everything is provided by Spring, so it's not apples-to-apples comparison.