Java member variables static variable code block static code fast load order

Preface

Base Class A

Class B inheritance implements Class A

1 The class is loaded first when you start an instance of new B . (Classes are loaded by the Java class loader only when they are created with the New call) 2 A , then load the subclass B
3 , after loading the parent class A , complete the static action (including static code and variables, their levels are the same, the order in which they appear in the installation code is initialized)
4 , after loading subclass B , Complete static action

1 B , first instantiate the parent class A
2 , instantiating the parent class A , first member instantiation (non-static code)
3 a
4 B
5 , subclass B Construction method

Initialize the static code of the parent class first ---> initializing the static code of a subclass - initializes the non-static code of the parent class ---> initializes the parent class constructor ---> Initialize subclass non-static code ---> Initialize subclass Constructors

Test code:

Abstract class Base
{
public int Age=getnumber (100);
static{
System.out.println ("Base static block");
}

{
System.out.println ("Base nonstatic block");
}
static int Sage=getnumber (50);
Base () {
System.out.println (age);
System.out.println ("base start");
Draw ();//Will call the subclass override method, here is 0!
System.out.println ("base End");
}
static int getnumber (int base) {
SYSTEM.OUT.PRINTLN ("Base.getnumber int" +base);
return base;
}
public void Draw () {
System.out.println ("Base.draw");
}
}

public class Initializeorder extends base{
public int Age=getnumber (1001);
private int _radius=getnumber (10);
static int Sage=getnumber (250);
static{
System.out.println ("Subclass static Block");
}
{
System.out.println ("Subclass nonstatic block");
}
Initializeorder (int radius) {
_radius=radius;
System.out.println (age);
Draw ();//here is 1000.
System.out.println ("Initializeorder initialized");
}
public void Draw () {
System.out.println ("Initializeorder.draw" +_radius);
}
public static void Main (string[] args) {//TODO auto-generated method stub
New Initializeorder (1000);

}

}

The output is:

Base static block
Base.getnumber Int50
Base.getnumber int250
Subclass Static Block
Base.getnumber int100
Base nonstatic block
100
Base Start
Initializeorder.draw 0
Base End
Base.getnumber int1001
Base.getnumber int10
Subclass Nonstatic Block
1001
Initializeorder.draw 1000
Initializeorder initialized

This article is from the "Android IOS" blog, so be sure to keep this source http://lovely1133.blog.51cto.com/1612511/1694264

Java member variables static variable code block static code fast load order