Hello. Thanks for article. Interesting thoughs. But I want to notice:

Standard Java enums can’t support a different kind of associated values per case so this means that we can’t have something like:

MONDAY(1),
TUESDAY(2),
WEDNESDAY(3),
THURSDAY(4),
FRIDAY(5),
SATURDAY(“WEEKEND”),
SUNDAY(“WEEKEND”);

Technically, you can do that. Here is a dummy sample that shows you that possibility:

public enum Files {
    FILE_METALLICA_NEM("Nothing else matters"),
    FILE_FILM_COUNT(3),
    FILE_COMPLEX(new ComplexFile(0, 1, 0, 0, 0, 1, 0));

    public final int dataInt;
    public final String dataStr;
    public final ComplexFile dataComplex;

    Files(int dataInt) {
        this.dataInt = dataInt;
        this.dataStr = null;
        this.dataComplex = null;
    }

    Files(String dataStr) {
        this.dataInt = 0;
        this.dataStr = dataStr;
        this.dataComplex = null;
    }

    Files(ComplexFile dataComplex) {
        this.dataInt = 0;
        this.dataStr = null;
        this.dataComplex = dataComplex;
    }
}
public class ComplexFile {
    public final int[] someComplexData;

    public ComplexFile(int... someComplexData) {
        this.someComplexData = someComplexData;
    }
}
//simple check test
public class Test {
    @org.junit.Test
    public void test() {
        Assert.assertEquals(Files.FILE_METALLICA_NEM.dataStr, "Nothing else matters");
        Assert.assertEquals(Files.FILE_FILM_COUNT.dataInt, 3);
        Assert.assertArrayEquals(Files.FILE_COMPLEX.dataComplex.someComplexData, new int[] { 0, 1, 0, 0, 0, 1, 0 });
    }
}