Why should I create a static method and not one that could instantiate the class and use this method?

Question

I really don’t see any difference in these two methods uses. Could someone be more specific with me and inform me about this?

Answer 1

A static method should be created if it makes sense to have it without an instance of the Object.

Simple example: in a class Geladeira you may have a static method double converterCelsiusFahrenheit(double celsiu) even if it does not have a refrigerator. Already the method void adicionarItem(Item item) is referencing a specific refrigerator, so it shouldn’t be static, since it needs an instance.