# -XX:+UseZGC -XX:-ZGenerational -Xlog:gc+init -version : generational ZGC is the only ZGC from Java 24 (JEP 490)

$ java -XX:+UseZGC -XX:-ZGenerational -Xlog:gc+init -version      (JDK 21)
    [0.004s][info][gc,init] Version: 21.0.12.1+9-LTS (release)
    [0.004s][info][gc,init] Using legacy single-generation mode

$ java -XX:+UseZGC -XX:-ZGenerational -Xlog:gc+init -version      (JDK 25)
    OpenJDK 64-Bit Server VM warning: Ignoring option ZGenerational; support was removed in 24.0
    [0.004s][info][gc,init] Version: 25.0.4.1+1-LTS (release)

$ java -XX:+UseZGC -XX:-ZGenerational -Xlog:gc+init -version      (JDK 26)
    Unrecognized VM option 'ZGenerational'
    Error: Could not create the Java Virtual Machine.

$ java -XX:+UseZGC -XX:-ZGenerational -Xlog:gc+init -version      (JDK 27)
    Unrecognized VM option 'ZGenerational'
    Error: Could not create the Java Virtual Machine.

$ java -XX:+UseZGC -XX:-ZGenerational -Xlog:gc+init -version      (JDK 23, Corretto image)
    OpenJDK 64-Bit Server VM warning: Option ZGenerational was deprecated in version 23.0 and will likely be removed in a future release.
    [0.004s][info][gc,init] Version: 23.0.2+7-FR (release)
    [0.004s][info][gc,init] Using deprecated non-generational mode

$ java -XX:+UseZGC -XX:-ZGenerational -Xlog:gc+init -version      (JDK 24, Corretto image)
    OpenJDK 64-Bit Server VM warning: Ignoring option ZGenerational; support was removed in 24.0
    [0.005s][info][gc,init] Version: 24.0.2+12-FR (release)