Duplicate Spring Boot 2/3 starter and autoconfigure modules for Spring Boot 4

[adinauer]

After my first attempt at fixing #14363, in #14415, I instead tried creating new modules for supporting Spring Boot 4.

New modules:

• spring-boot-autoconfigure-4.0
• spring-boot-starter-4.0

I've set both of them as otel.stable=false, so they're released as alpha version.

I've confirmed this to work with Spring Boot 4 on one of our Sentry sample applications by publishing to my local Maven repository. The ClassNotFoundException for org.springframework.boot.autoconfigure.web.client.RestClientAutoConfiguration is gone and the application starts up.

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: adinauer / name: Alexander Dinauer (acd7c8c)
• ✅ login: otelbot[bot] (e827295)

[otelbot-java-instrumentation]

🔧 The result from spotlessApply was committed to the PR branch.

[laurit]

Since #14363 was resolved is this still relevant?

[adinauer]

My understanding is you would prefer it to be implemented differently. Afaik there's currently no support for Spring Boot 4 and #14363 only fixed the exceptions but didn't implement the required functionality. LMK if I'm wrong.

[laurit]

My understanding is you would prefer it to be implemented differently.

Correct, duplicating all the code seems excessive. I would prefer not to do it if possible.

Afaik there's currently no support for Spring Boot 4 and #14363 only fixed the exceptions but didn't implement the required functionality. LMK if I'm wrong.

Correct. Since we don't have tests for spring 4 can't say with certainty but some instrumentation should still work while some others, that use classes that were moved in spring 4, were disabled.