什么时候用

[pleasanton]

1. Class/static variables

2. Abstract Class／Abstract Methods

3. static method

public class Animal {
    public static  void foo() {
        System.out.println("Animal");
    }
}
 
public class Cat extends Animal {
    public static void foo() {  // hides Animal.foo()
        System.out.println("Cat");
    }
}
 
 
public class MethodHiding {
    public static void main(String[] args){
         
        Animal.foo(); // prints Animal
	Cat.foo(); // prints Cat

	Animal a = new Animal();
	Animal b = new Cat();
	Cat c = new Cat();
	Animal d = null;
 
        a.foo();  
        b.foo();  
        c.foo();  
        d.foo();
    }
 
}

prints:

Animal
Cat
Animal
Animal
Cat
Animal

[pleasanton]

Here, Cat.foo() is said to hide Animal.foo(). Hiding does not work like overriding, because static methods are not polymorphic.

[S117]

楼主在炫耀英语吗？

[pleasanton]

初中生就懂的几句英文，有啥好炫耀的？