Initialization of Java classes and the order in which objects are created

Learn the idea of Java programming--class initialization p146

The order in which classes are loaded
* 1 Loader startup find Xxx.class file, search base class by extends keyword, load base class first
* Class 2 initialization initializes static member variables and static--->
* 2 Initialize the static member variable and static of the parent class first
* 3 Re-initializes the static member variable and static for this class

* After class loading, object creation begins
* 1 Load the non-static member variable of the parent class first (static member variables are loaded when the class is initialized, and non-static member variables are initialized with the creation of the object)
* 2 Load the constructor of the parent class first
* 3 Reload non-static member variables of this class
* 4 Load the constructor of this class again
*

Overall:
*--Indicates the order
* Parent Class--child class
* Static---Non-static
* Class-to-Object
* Static loads with class loading
* Non-static member variables are loaded with the creation of the object
* Member variables are loaded before the constructor

1  Packagecom.test.java.classs;2 3 /**4 * Created by Administrator on 2015/12/8.5 * Load order of Classes6 * 1 Loader startup find Xxx.class file, search base class by extends keyword, load base class first7 * Class 2 initialization initializes static member variables and static--->8 * 2 Initialize the static member variable and static of the parent class first9 * 3 Re-initializes the static member variable and static for this classTen * After class loading, object creation begins to load One * 1 Load the non-static member variable of the parent class first (static member variables are loaded when the class is initialized, and non-static member variables are initialized with the creation of the object) A * 2 Load the constructor of the parent class first - * 3 Reload non-static member variables of this class - * 4 Load the constructor of this class again the  * - * Overall: - * --Indicates the order - * Parent Class--child class + * Static---Non-static - * Class -to-object + * static loads with class loading A * Non-static member variables are loaded with the creation of the object at * Member variables are loaded before the constructor -  * -  */ -  Public classClassloadorderextendsfather{ -     //2 The static domain of the child class is loaded after the static member variable of the parent class is loaded -     Private Static intK = Printint ("Child static K initialized"); in     //5 Initialization of non-static member variables for subclasses -     Private intm = printint ("Child non-static variable load"); to  +     //the constructor of the child class is loaded -      PublicClassloadorder () { theSystem.out.println ("Child constructor initialized"); *System.out.println ("k=" +k); $System.out.println ("j=" +j);Panax Notoginseng     } -  the     Static { +SYSTEM.OUT.PRINTLN ("Child static Initialized"); A     } the     Static intPrintInt2 () { +SYSTEM.OUT.PRINTLN ("Child static function initialized"); -         return50; $     } $  -      Public Static voidMain (string[] args) { -Classloadorder C =NewClassloadorder (); the     } - }Wuyi  the classfather{ -     Private intI=9; Wu     protected intJ; -     //4 Parent class constructor loading About Father () { $System.out.println ("Father constructor initialized"); -System.out.println ("i=" +i+ ", j=" +j); -j=39; -     } A     //3 When an object is created, initialize the non-static member variable of the parent class first +     intn = printint ("Father non-static variable loading"); the     //1 Load the static domain of the parent class first -     Static { $System.out.println ("Father Static initialized"); the     } the     //1 the     Private Static intX1 = Printint ("Father Static. X1 Initialized"); the     Static intPrintint (String s) { - System.out.println (s); in         return47; the     } the}

Results:

Father Static initialized
Father Static. X1 Initialized
Child static k initialized
Child static initialized
Father non-static variable loading
Father Constructor initialized
I=9,j=0
Child non-static variable loading
Child constructor initialized
k=47
j=39

Initialization of Java classes and the order in which objects are created