Performance, namespace pollution etc are all secondary in my view. Ask yourself what is logical. Is the method logically operating on an instance of the type, or is it related to the type itself? If it’s the latter, make it a static method. Only move it into a utility class if it’s related to a … Read more
The Answer Just use TheClassName.class instead of getClass(). Declaring Loggers Since this gets so much attention for a specific usecase–to provide an easy way to insert log declarations–I thought I’d add my thoughts on that. Log frameworks often expect the log to be constrained to a certain context, say a fully-qualified class name. So they … Read more
Java 8 permits static interface methods With Java 8, interfaces can have static methods. They can also have concrete instance methods, but not instance fields. There are really two questions here: Why, in the bad old days, couldn’t interfaces contain static methods? Why can’t static methods be overridden? Static methods in interfaces There was no … Read more
Overriding depends on having an instance of a class. The point of polymorphism is that you can subclass a class and the objects implementing those subclasses will have different behaviors for the same methods defined in the superclass (and overridden in the subclasses). A static method is not associated with any instance of a class … Read more
One rule-of-thumb: ask yourself “Does it make sense to call this method, even if no object has been constructed yet?” If so, it should definitely be static. So in a class Car you might have a method: double convertMpgToKpl(double mpg) …which would be static, because one might want to know what 35mpg converts to, even … Read more
Because “abstract” means: “Implements no functionality”, and “static” means: “There is functionality even if you don’t have an object instance”. And that’s a logical contradiction.
Though classmethod and staticmethod are quite similar, there’s a slight difference in usage for both entities: classmethod must have a reference to a class object as the first parameter, whereas staticmethod can have no parameters at all. Example class Date(object): def __init__(self, day=0, month=0, year=0): self.day = day self.month = month self.year = year @classmethod … Read more
Yep, using the staticmethod decorator: class MyClass(object): @staticmethod def the_static_method(x): print(x) MyClass.the_static_method(2) # outputs 2 Note that some code might use the old method of defining a static method, using staticmethod as a function rather than a decorator. This should only be used if you have to support ancient versions of Python (2.2 and 2.3): … Read more