CODEWITHSUNDEEP
javaenumsequals
user1056903
user1056903

Reputation: 941

Use == for comparison if enum only on one side

If an enum constant is compared with something else, is it permissible to use == in place of the equals method?

Example (User implements the interface IUser): 

IUser peter = User.PETER;
if (User.PETER == peter) {
// do something
}

Upvotes: 0

Views: 85

Answers (1)

mentallurg
mentallurg

Reputation: 5207

In your code we assume that your enumeration User implements interface IUser. Otherwise the code IUser peter = User.PETER; would compile.

Yes, it is safe. Because in the class loader there can be a single instance of each enumeration. This means, there can be only a single instance of each enumeration value. These values cannot be created by some other mechanism. That's why if there are two variables representing the same enumeration value, it must be the same instance. That's why simple comparison by == is sufficient.

Upvotes: 1

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