Congrats!
Are there any notable differences from the german edition?

In a distributed system, after "reloading" an object you might need to reattach it to an existing object graph and propagate it. Equals checks via state or id/version won't do, as they might have not changed, but the instance has changed nevertheless.

Yes, but we want to avoid the "-am" option in this case to avoid testing unaffected modules, so we need to resort to installing with m3.
Hopefully, Maven 4 will offer enhancements in this regard, but I did not try yet.

But how do you test a subset of modules of a multi-module build?
Imagine a CI pipeline that has compiled everything in the previous stage and now wants to test the affected modules by a change. Using options "-pl -amd" will lead to a test classpath referencing Jars in local repo last time I checked.