Weird classloader issue

[schauder]

With Open JDK 17 I get a weird exception message when my entity is package private, while it works fine, when the entity is public.

Error message:

java.lang.IllegalAccessError: failed to access class com.tsdjb.chapter1.BoardGame from class jdk.proxy2.$Proxy70 (com.tsdjb.chapter1.BoardGame is in unnamed module of loader 'app'; jdk.proxy2.$Proxy70 is in module jdk.proxy2 of loader 'app')

Reproducer: up coming
The actual project is in the subdirectory chapter1.

Running ./mvnw clean verify demonstrates the error. Changing the BoardGame class to public resolves it.

The problem occurs when using getByName, not when using getById.

[mp911de]

This is perfectly valid. The proxy is in the package jdk.proxy2 while your package-private entity is in the com.tsdjb.chapter1 package. Accessing a package-private class in com.tsdjb.chapter1 from jdk.proxy2 would violate the JVM rules. Switching the repository interface to package-private lets the proxy generator generate the proxy class in the com.tsdjb.chapter1 which satisfies access rules.