$ javac --release 21 broken/OnJdk21.java     (25.0.4.1+1)
OnJdk21.java:7: error: flexible constructors is not supported in -source 21
            super(name.strip());
                 ^
  (use -source 25 or higher to enable flexible constructors)
1 error
exit=1

$ javac --release 24 broken/OnJdk21.java     (25.0.4.1+1)
OnJdk21.java:7: error: flexible constructors is not supported in -source 24
            super(name.strip());
                 ^
  (use -source 25 or higher to enable flexible constructors)
1 error
exit=1

$ javac --release 25 broken/OnJdk21.java     (25.0.4.1+1)
exit=0