Java-deep Java Virtual Machine 3

The initialization time of the class

 Packagepractise;classparent{Static intA =3; Static{System.out.println ("Parent static Block"); }}classChildextendsparent{Static intb = 4; Static{System.out.println ("Child Static Block"); }} Public classTest4 {Static{System.out.println ("Test4 static Block"); }     Public Static voidMain (string[] args) {System.out.println (child.b); }}

Result:
TEST4 static block
Parent static block
Child static Block
4

 Packagepractise;classparent5{Static intA =3; Static{System.out.println ("PARENT5 static Block"); }}classChild5extendsparent5{Static intb = 4; Static{System.out.println ("Child5 static Block"); }} Public classTEST5 {Static{System.out.println ("Test5 static Block"); }     Public Static voidMain (string[] args) {Parent5 parent=NewParent5 ();        System.out.println (PARENT5.A);            System.out.println (child5.b); }}

Result:
TEST5 static block
PARENT5 static block
3
CHILD5 static block
4

The "active use" of a child class in a program causes the parent class to be initialized, but the "active" use of the parent class does not cause the child class
Initialization

Calling the LoadClass method of the ClassLoader class to load a class is not an active use of the class and does not cause the initialization of the class.

 Packagepractise;classc{Static{System.out.println ("Class C"); }} Public classTest6 { Public Static voidMain (string[] args) {ClassLoader loader=Classloader.getsystemclassloader (); Try{Class<?> CLZ = Loader.loadclass ("practise. C); System.out.println ("----------------"); CLZ= Class.forName ("practise. C); } Catch(ClassNotFoundException e) {//TODO auto-generated Catch blockE.printstacktrace (); }    }}

Result:
----------------
Class C

Java-deep Java Virtual Machine 3