Matters of parent-child class construction method in inheritance

Matters of parent-child class construction method in inheritance

1、 In an inheritance relationship , The subclass must call the constructor of the parent class , There is an implicit in the subclass constructor “super()” call , So you must call the constructor of the parent class first , Construction of post execution subclass .
Be careful super() Is the parameterless constructor of the parent class of the call .

Public Zi(){
    
	super();// Default implies , If you don't write, there will be 
	sout:" Subclass construction method ";
}

2、 Subclass construction can be done by super Keyword calls the parent class overload constructor
3、 Only child class constructors can call parent class constructors
4、super() The parent class construct of calls , Must be the first statement of subclass construction .
5、 A subclass construct cannot be called more than once super() structure .