Cannot run or debug a project after upgrade to NB21

[gsteri1]

Hi!

I was developing a relatively complicated Java app in Netbeans18. I reached a stable point in my code and wanted to update the IDE. I installed using the exe installer on a Windows10 machine. I opened my project and dependencies. Netbeans21 converted the project files and everything seemed normal. I did a clean and build and the project built, all the new jars appeared. Everything looked good. I attempted to run a class in the generated jar.

I got an error like the following:

Error: Could not find or load main class com.example.AClass in module jdk.internal.vm.compiler

The project is a plain netbeans project that I've updated since circa 2017. It uses the standard ANT build process with NO overrides on my part. I placed some echo commands in the build-impl.xml and can verify that the class path points to dist/classes (in addition to the dependencies the main project has). Similarly, I get the error when I attempt to debug. I can see the class in the dist/classes directory. I can see the jar is created. There are warnings, but no errors.

This feels like a problem where something in a .properties file is missing, but I can't see anything obvious. I have tried changing the src to java20, in hopes whatever is missing would be overwritten, but nothing.