java - What is the point of OptionalInt?

Question

This question already has answers here: question from:https://stackoverflow.com/questions/65646978/what-is-the-point-of-optionalint

Answer 1

First of all, remember that there might be no value present after the filter method usage (or any that returns a different number of objects like reduce). It is not guaranteed that a value would be always present. That's behind the design of returning something that says that the value might be there instead of null that likely causes errors.

Is it really worth having OptionalInt just for that single return object at the end?

Yes, it is worth it. OptionalInt is a representation of Optional<Integer> that returns a primitive int instead (of course the value must be present). We can say it wraps int. Since boxing is related only to primitives, I guess introducing such object/s is for sake of convenience and boxing operation overhead avoidance.

OptionalInt optionalInt = IntStream.range(0, 10)
        .filter(i -> i > 5)
        .map(i -> i + 1)
        .findAny();
int resultInt1 = optionalInt.getAsInt();  // PROS: explicit method name advantage

Optional<Integer> optional =  IntStream.range(0, 10)
        .filter(i -> i > 5)
        .mapToObj(i -> i + 1)             // CONS: boxing (int -> Integer)
        .findAny();
int resultInt2 = optional.get();          // CONS: boxing (Integer -> int)
                                          // CONS: not explicit method name