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javascjp

A SCJP Question on topic Enums

From the SCJP Questions PDF book, I got this question..

1. enum Animals {
2. DOG("woof"), CAT("meow"), FISH("burble");
3. String sound;
4. Animals(String s) { sound = s; }
5. }
6. class TestEnum {
7. static Animals a;
8. public static void main(String[] args) {
9. System.out.println(a.DOG.sound + " " + a.FISH.sound);
10. }
11. }

The Options are,

A. woof burble

B. Multiple compilation errors

C. Compilation fails due to an error on line 2

D. Compilation fails due to an error on line 3

E. Compilation fails due to an error on line 4

F. Compilation fails due to an error on line 9

A is the correct Answer,..

Can some body explain this..

Whether the enum can have constructors?

Solution

  • Yes, enums can have constructors and methods and instance variables just like other classes. But you cannot call the constructor yourself, like you would with a regular class. You can't call a= new Dog("wooooof"). The constructor will be called by the compiler for you.

    This will compile fine, but on line 9, I think the compiler will warn you that you are accesing a static field in a a non-static way. Animal.DOG.sound is the "proper way" and not a.DOG.sound.