$ java broken/PrivateCtor.java     (OpenJDK Runtime Environment Temurin-25.0.4.1+1 (build 25.0.4.1+1-LTS))
instance main() reached through a PRIVATE zero-argument constructor

$ java broken/PrivateCtor.java     (OpenJDK Runtime Environment Temurin-27+35 (build 27+35))
error: no non-private zero argument constructor found in class PrivateCtor
remove private from existing constructor or define as:
   public PrivateCtor()