Is it possible to call a super static method from child static method?
I mean, in a generic way, so far now I have the following:
public class BaseController extends Controller {
static void init() {
//init stuff
}
}
public class ChildController extends BaseController {
static void init() {
BaseController.loadState();
// more init stuff
}
}
and it works, but I'd like to do it in a generic way, something like calling super.loadState(), which doesn't seem to work...
In Java, static methods cannot be overidden. The reason is neatly explained here
So, it doesn't depend on the object that it is being referenced. But instead, it depends on the type of reference. Hence, static method is said to hide another static method and not override it.
For example (Cat is a subclass of Animal):
public class Animal {
public static void hide() {
System.out.format("The hide method in Animal.%n");
}
public void override() {
System.out.format("The override method in Animal.%n");
}
}
public class Cat extends Animal {
public static void hide() {
System.out.format("The hide method in Cat.%n");
}
public void override() {
System.out.format("The override method in Cat.%n");
}
}
Main class:
public static void main(String[] args) {
Cat myCat = new Cat();
System.out.println("Create a Cat instance ...");
myCat.hide();
Cat.hide();
myCat.override();
Animal myAnimal = myCat;
System.out.println("\nCast the Cat instance to Animal...");
Animal.hide();
myAnimal.override();
Animal myAnimal1 = new Animal();
System.out.println("\nCreate an Animal instance....");
Animal.hide();
myAnimal.override();
}
Now, the output would be as given below
Create a Cat instance ...
The hide method in Cat.
The hide method in Cat.
The override method in Cat.
Cast the Cat instance to Animal...
The hide method in Animal.
The override method in Cat.
Create an Animal instance....
The hide method in Animal.
The override method in Animal.
For class methods, the runtime system invokes the method defined in the compile-time type of the reference on which the method is called.
In other words, call to static methods are mapped at the compile time and depends on the declared type of the reference (Parent in this case) and not the instance the reference points at runtime. In the example, the compile-time type of myAnimal is Animal. Thus, the runtime system invokes the hide method defined in Animal.
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