Class loading is broken with Spring Boot's DevTools again.

Hello Luke,

Sadly #331 introduced a regression of #267.

That became apparent in a change of Neo4j-OGM where we now rely on ClassGraph being able to find scanned classes.

Find attached a reproducer:

try(ScanResult r = new ClassGraph()
			.ignoreClassVisibility()
			.whitelistPackages("com.example.gh729.domain")
			.scan()) {

			for(ClassInfo classInfo : r.getAllClasses()) {
				if("com.example.gh729.domain.SomeClass".equals(classInfo.getName())) {
					SomeClass f = (SomeClass) classInfo.loadClass().getConstructor().newInstance();
				}
			}
		}

This works in 4.8.17 and starts to fail in 4.8.19 again (as before my contribution).

This is the expected order of class loaders withorg.springframework.boot.devtools.restart.classloader.RestartClassLoader present

This is now what I get in 4.8.19+

Both screenshots from debugging into io.github.classgraph.ClassGraphClassLoader and displaying the order of class loaders used.

Find the reproducer attached. Open in your IDE and run Gh729Application.

gh729.zip

Related OGM ticket is https://github.com/neo4j/neo4j-ogm/issues/729

[lukehutch]

Actually now that I understand the Restart classloader better, I made some further cleanups to simplify the ClassLoaderHandler in the last commit. Please check also that 4.8.61-SNAPSHOT (the git master version) works for you in addition to 4.8.60. (The master version should also work fine.)

[michael-simons]

Great work, Luke! I can confirm both 4.8.60 and 4.8.61-SNAPSHOT works.