Thinking in java ： polymorphism

static methods are associated with the class , not with individual objects

public class Base{

public static void say(){

System.out.println(“Base say”);

}

}

}

public class Devide extends Base{
public static void say(){
System.out.println("Devide say");
}
public static void main(String []args){
Devide devide = new Base();
devide.say();
// output: "Base say"
}
}

Only non-private methods may be overridden

Orders of constructor calls, base-Class constructor > member initialization > self-Class constructor

key words: Upcast, late-binding, polymorphism, implements, inheritance, abstract