Is it OK to use == on enums in Java?

Question

Is it OK to use == on enums in Java, or do I need to use .equals()? In my testing, == always works, but I\'m not sure if I\'m guarant

Answer 1

Yes, == is fine - there's guaranteed to be just a single reference for each value.

However, there's a better way of writing your round method:

public int round(RoundingMode roundingMode) {
  switch (roundingMode) {
    case HALF_UP:
       //do something
       break;
    case HALF_EVEN:
       //do something
       break;
    // etc
  }
}

An even better way of doing it is to put the functionality within the enum itself, so you could just call roundingMode.round(someValue). This gets to the heart of Java enums - they're object-oriented enums, unlike the "named values" found elsewhere.

EDIT: The spec isn't very clear, but section 8.9 states:

The body of an enum type may contain enum constants. An enum constant defines an instance of the enum type. An enum type has no instances other than those defined by its enum constants.