无法创建java 9 JAR

如果我运行命令 jar --create --release 9 -C com.java.mrjar.nine\build\classes .

entry: META-INF/versions/9/com/java/mrjar/nine/Main.class, contains a new public class not found in base entries
entry: META-INF/versions/9/com/java/mrjar/nine/TimeUt.class, contains a new public class not found in base entries
invalid multi-release jar file mrjars\com.java.mrjar.jar deleted

以下是主要和TimeUt类:

package com.java.mrjar.nine;
import java.time.Instant;
public class Main {
    public static void main(String[] args) {
        System.out.println("Inside jdk9 Main.main()...");
        TimeUt t = new TimeUt();
        System.out.println("Local Date: "+t.getLocalDate(Instant.now()));
    }
}

package com.java.mrjar.nine;
import java.time.Instant;
import java.time.LocalDate;
import java.time.ZoneId;
public class TimeUt {
    public TimeUt() {
        System.out.println("creating jdk9 version of TimeUt");
    }
    public LocalDate getLocalDate(Instant now){
        return LocalDate.ofInstant(now, ZoneId.systemDefault());
    }
}

我可以正常创建jar,而无需添加 --第9版 版本>9