Equals Method in Enum Type

Question

public enum EnumEqualsMethod {

    A,B,C

}


public enum EnumEqualsMethod1 {

    A,C,D

}

EnumEqualsMethod a =  EnumEqualsMethod.C;
ЕnumEqualsMethod1 b=  EnumEqualsMethod1.C;

System.out.println(a.equals(b));

Output is false.Why?

possible duplicate of [Comparing Java enum members: == or equals()?](http://stackoverflow.com/questions/1750435/comparing-java-enum-members-or-equals) — Smutje, Dec 19 '14 at 11:36
It's not because they have the same name that they are equals. Even if they are enums, they are still objects. — Alexis C., Dec 19 '14 at 11:44

score 5 · Accepted Answer · answered Dec 19 '14 at 11:36

5

Enums are compared as Objects. These are two distinct objects of different classes. Why should they be equal? A,B,C - are just names of variables. They mean nothing in comparison operation.

answered Dec 19 '14 at 11:36

Mikhail

4,175
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31

we can't use equals method for constants in different enum classes.Right? – Furkan Aktaş Dec 19 '14 at 11:38
You should understand difference between reference, reference name and object. Once again reference names do not mean equality of objects. – Mikhail Dec 19 '14 at 11:40
1

You can use `equals()` for `enum` constants, but there's no point. It's the same as `==` for `enum`. One great thing about java `enum`s is that they each have their own name-space, so `C` in `EnumEqualsMethod` has nothing to do with `C` in `EnumEqualsMethod1`. – Paul Boddington Dec 19 '14 at 11:44

score 0 · Answer 2 · answered Dec 19 '14 at 11:44

In order to understand why the output is false you should think of EnumEqualsMethod as a Class and A, B, C as Instances of that Class.

For example the comparison of the Enums is like doing the following:

Class1 a = new Class1();
Class2 b = new Class2();

System.out.print(a.equals(b));

Equals Method in Enum Type

2 Answers2