Spike - Investigate possible ways to determine what annotations exist on classes which implement interfaces that contain annotations.

[jtduffy]

The problem with annotating interfaces is that those annotations are lost at runtime on the implementing classes. So when you have a controller that implements an interface, and that interface's methods are annotated with a Spring mapping annotation, we can't pick that up, so we have to default to the method name. See the javadoc for Annotation Type Inherited :

Note also that this meta-annotation only causes annotations to be inherited from superclasses; annotations on implemented interfaces have no effect

The goal of the spike is to see if there is any way to determine these annotations at runtime, possible through reflection of the target interface(s) to fetch annotations and map those to classes that implement the interface(s).

[workato-integration]

https://new-relic.atlassian.net/browse/NR-177700

[jtduffy]

@mgr32
Snapshot artifact

We have 3 modules:

• spring-4.3.0: This is a replacement for the existing 4.3.0 module
• spring-6.0.0: This is identical to 4.3.0 except for the namespace change of javax --> jakarta
• instrumentation:spring-webflux-controller-mappings-5.0.0: Same functionality as the previous modules, just for webflux based controllers

The legacy controller pointcut has also been removed.

The README for the 4.3.0 module gives a decent overview of what should be supported.

If you see any issues, have any code comments, etc, let me know. If all goes well, this change will be part of our first release in 2024.