The reliability of the migration procedure is not guaranteed.

[PhilippSalvisberg]

This error message ORA-29548: Java system class reported: could not find classes.bin version that matches executable version 23.8.0.25.2504154.0 11 is thrown when I run the next statement in my 25-3 environment, which was migrated from a previous version.

create or replace and compile java source named "Util" as
public class Util {
   public static long toEpoch(java.sql.Timestamp ts) {
      return ts.getTime();
   }
   public static void print(String in_text) {
      System.out.println(in_text);
   }
}
/

It works in a freshly set-up environment. I guess the problem is that the migration procedure assumes that the database volume is compatible. Which is probably true for a lot of things, but for sure not for Java. Maybe also for other things. I do not know.

The problem is that this simplified migration procedure is fast, but may lead to issues which look like an Oracle Database problem but are the result of the simplified migration procedure.

I don't know what the proper solution is, since the free edition does not support migrations. So setting up the environment from scratch seems the only fully reliable solution, which is, of course, very cumbersome.

Maybe just adding a warning to the documentation of the migration procedure is good enough, with the hint that if you run into problems, you should set up a fresh environment.