Why should Java 8's Optional not be used in arguments

Question

I\'ve read on many Web sites Optional should be used as a return type only, and not used in method arguments. I\'m struggling to find a logical reason why. For example I h

Answer 1

At first, I also preferred to pass Optionals as parameter, but if you switch from an API-Designer perspective to a API-User perspective, you see the disadvantages.

For your example, where each parameter is optional, I would suggest to change the calculation method into an own class like follows:

Optional p1 = otherObject.getP1();
Optional p2 = otherObject.getP2();

MyCalculator mc = new MyCalculator();
p1.map(mc::setP1);
p2.map(mc::setP2);
int result = mc.calculate();