are java enums singleton? [duplicate]

Question

This question already has answers here:

Understanding Enums in Java (6 answers)

Life span of a Java enum instance (2 answers)

Comparing Java enum members: == or equals()? (15 answers)

Closed 7 years ago.

do java enums are singleton?

for example :

public enum State {

ACTIVE(0),
PENDING(1),
DELETED(2),
}


State s = State.ACTIVE;
State s2 = State.PENDING;
State s3 = State.PENDING;

is java create new instances every time we use State.FOO ??

Your enum has exactly three instances (ACTIVE, PENDING and DELETED) (or would if it was valid code). It does not create new instances every time you reference it. If you had only one element in your enum, instead of three, it would be a singleton. — khelwood
– khelwood, Commented Dec 20, 2017 at 16:05
"Because there is only one instance of each enum constant, it is permitted to use the ==operator in place of the equals method when comparing two object references if it is known that at least one of them refers to an enum constant." (JLS Sec 8.9.1) — Andy Turner
– Andy Turner, Commented Dec 20, 2017 at 16:07

cdbbnny · Accepted Answer · 2017-12-20 16:26:26Z

9

Enums in java are classes with several constant instances of themselves. These are created like static final variables. Accessing an enum constant returns a reference to the enum constant. It does not create a new instance of the enum constant.

answered Dec 20, 2017 at 16:26

cdbbnny

3302 silver badges9 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

are java enums singleton? [duplicate]

1 Answer 1

Comments

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Linked

Related