Ensure that a static method is implemented

Question

I have several Java classes which contain static methods. I want to ensure that these static methods are implemented by each of the classes. How can I enforce that, since declaring static methods is not allowed in interfaces in Java?

Answer 1

Sort answer: You can't enforce that.

Static methods are not inherited the same way as instance methods, so you wouldn't be able to use it for anything meaningful anyway: You can't call MySuperClass.staticMethod() and expect some subclass to handle the call. This means that you have to call it using MySubClass.staticMethod() in which case you'll get a compilation error if MySubClass doesn't implement staticMethod.

I would suggest you look into solving it using a singleton or factory pattern and use instance methods:

MySuperClass.getInstance(parameter).yourMethod()

Answer 2

static methods are allowed on interfaces in Java8.

However, there's no way to enforce a class to implement a static method.

The only thing you can do, is make them non-static and abstract (either in an interface or in an abstract class).

Answer 3

If you have code that calls these methods, it won't pass compilation if they are not implemented. If you don't, you don't really need them.