Java constructor Call Sequence

Java beginners

Like C ++, if Java has inheritance, it first calls the constructor of the parent class and then calls the constructor of the subclass. If a class object has a member, it is called

Before the constructor of this class, you must call the constructor of the class member variable.

Eg.

Class

{

A () // Constructor

{

System. Out. println ("Class A constructor! ");

}

}

Class B

{

B () // Constructor

{

System. Out. println ("Class B constructor! ");

}

}

Public Class C extends a // Class A is the parent class of class C

{

B = new B (); // Class C contains class B objects as member variables

C ()

{

System. Out. println ("Class C constructor! ");

}

 

Public static void main (string ARGs [])

{

C = new C ();

}

}

Output result

First, go to the public class. before calling the C constructor, call the constructor of the parent class, initialize the member variable, and call the constructor of the B class,

Finally, call the member functions of class C.