How I am able to access the enum value just by reference, where reference itself is null?

Asked Feb 19 '19 at 12:09

Active Feb 19 '19 at 12:09

Viewed 27 times

I have this following code:

enum Animals{
    DOG("woof"), CAT("meow"), FISH("burble");
    String sound;
    Animals(String s){ sound = s; }
}

class TestEnum{
    static Animals a;
    public static void main(String[] args){
        System.out.println(a + "   " +a.DOG);
    }
}

The output of this is:

null   DOG

I don't understand how I am able to access a.Dog where value of a is null. Can anyone explain this behavior?

asked Feb 19 '19 at 12:09

sanjiv saini

You haven't initialized the enum value `a`. Think of `a` as a static reference to all values inside the enum. – Sid Feb 19 '19 at 12:10
but why I am getting value for a.DOG? – sanjiv saini Feb 19 '19 at 12:11
Because DOG is `static` – Ayrton Feb 19 '19 at 12:11
'a' is just a reference without any object assigned to it – sanjiv saini Feb 19 '19 at 12:12
The enum values are static fields in the `Animals` class. You can always access a static field or method "with" a null reference to the containing class. – Andy Turner Feb 19 '19 at 12:12
Accessing a static field (here `DOG`) through an instance reference (here `a`) is poor style. Exactly because of the confusion it leads to in your case (among other reasons). Instead use `Animals.DOG`, and no confusion is possible. – Ole V.V. Feb 19 '19 at 12:15
Thanks @AndyTurner , It make sense now. I missed this rule. – sanjiv saini Feb 19 '19 at 12:21

How I am able to access the enum value just by reference, where reference itself is null?

0 Answers0