The execution order of Java parameter-free constructors

Here's a piece of code that uses an array construct stack to illustrate

1  Public classStackarray<e> {2 3     Privateobject[] data =NULL;4     Private intMaxSize;//Stack Capacity5     Private inttop =-1;//stack Top pointer6     7     /**8 * Override parameterless constructor9      */Ten Stackarray () { One          This(10);//The default stack size is 10 (if there is code in front of this line, this line will give an error) ASYSTEM.OUT.PRINTLN ("No parameter constructor execution"); -     } -      the     /** - * Parametric Constructors -      */ -Stackarray (intinitialsize) { +         if(initialsize >= 0){ -              This. maxSize =initialsize; +data =NewObject[initialsize]; Atop =-1; at}Else{ -             Throw NewRuntimeException ("Initialization size cannot be less than 0:" +initialsize); -         } -SYSTEM.OUT.PRINTLN ("parameter constructor execution")); -     } -      in      Public Static voidMain (string[] args) { -         NewStackarray (); to         //New Stackarray (a); +     } -}

1) New Stackarray () is an instantiation process without parameters:

Find the parameterless constructor > initialize the member variable (the reference type is initialized to null,int initialized to 0) > this (10) calls the parameter constructor > comes to the parameter constructor and initializes the assignment parameter (initialsize=10) > Member variable assignment (for example, top=-1) > Execute parameter Constructor internal code (output "parameter constructor execution") > Execute parameterless constructor internal code (output "No parameter constructor execution") > End

2) New Stackarray (20) has a parameter instantiation process:

Locate the parameter constructor > initialize the assignment parameter and initialize the member variable (the reference type is initialized to null,int initialized to 0) > member variable assignment (for example, Top=-1) > Execute code inside the Argument builder > End

3) If no parameter constructor is called within the parameterless constructor, the instantiation process of New Stackarray ():

Find parameterless constructor > Initialize member variable (reference type initialized to null,int initialized to 0) > member variable assignment (e.g. Top=-1) > execute parameterless constructor internal code (output "parameterless constructor execution") > End

The execution order of Java parameter-free constructors