Java module system: "access to public member failed" when using 'opens' x to 'y'

[mfdewit]

Describe the bug Allowing runtime-only access to a package by org.eclipse.yasson is not working. I have a module-info file containing the following statement:

opens nl.scuro.media.model to org.eclipse.yasson;

This should allow Yasson to be able to read this package when (de)serializing. Unfortunately, I get an error:

Caused by: java.lang.IllegalAccessException: access to public member failed: nl.scuro.media.model.MediaRefClientWrapper.getMediaRef[Ljava.lang.Object;@6af6a361/invokeVirtual, from public Lookup
	at java.base/java.lang.invoke.MemberName.makeAccessException(MemberName.java:955)

I can work around this by exporting my package: exports nl.scuro.media.model;

But I there are scenarios where one doesn't want to export globally.

To Reproduce Create a simple project with a module-info file and package containing a POJO. Add Yasson as a dependency and open this package to org.eclipse.yasson.

Expected behavior I would expect Yasson to be able to access all classes in the opened package.

System information:

• OS: Linux
• Java Version: 17
• Yasson Version: 2.0.4

Additional context While I'm not very experienced with the module system yet, this seems to be incorrect behavior.