Java程序初始化顺序

importjava.util.*;

publicclassDemo...{
static...{

System.out.println("iamstaticdemo.");
}
...{

System.out.println("iamdemo.");
}
staticvoidprint()...{
System.out.println("canomitinstanceinitialization?");
}
publicstaticvoidmain(String[]args)...{
newSub("child");
Demo.print();
}
}

abstractclassBase...{
publicStringname="";
publicStringsex="base";
publicBase(Stringname)...{
System.out.println("name:"+this.name);
this.name=name;
System.out.println("invokebaseconstructor");
System.out.println("name:"+name);
this.setName("parent");
}

...{
System.out.println("invokebaseinstanceblock");
System.out.println("this.sex:"+this.sex);
printInfo();
}

static...{
System.out.println("invokebasestaticblock");
}

//publicabstractvoidsetName();

publicabstractvoidprintInfo();

publicvoidsetName(Stringname)...{
this.name=name;
System.out.println("invokeparentsetNamemethod");
System.out.println("name:"+name);
}

}

classSubextendsBase...{
publicstaticintage=10;
publicStringsex="sub";
publicSub(Stringname)...{
super(name);
System.out.println("invokesubconstructor");
System.out.println("name:"+name);
}

...{
System.out.println("invokesubinstanceblock");
System.out.println("name:"+name);
}

static...{
System.out.println("invokesubstaticblock");
}

publicvoidprintInfo()...{
System.out.println(" ");
System.out.println("invokesubprintInfo");
System.out.println("age:"+age);
System.out.println("name:"+name);
System.out.println(" ");
}

publicvoidsetName(Stringname)...{
System.out.println("invokesubsetNamemethod");
this.name=name;
System.out.println("name:"+name);
}
}

输出结果；

i am static demo.
invoke base static block
invoke sub static block
invoke base instance block
this.sex:base

invoke sub printInfo
age:10
name:

name:
invoke base constructor
name:child
invoke sub setName method
name:parent
invoke sub instance block
name:parent
invoke sub constructor
name:child
can omit instance initialization?
初始化的实际过程为：

1. 在其它任何事物发生之前，将分配给对象的存储空间初始化成二进制的零。
2. 父类static 块或变量
3. 子类static块或变量
4. 父类的显式初始化
5. 父类构造函数
6. 子类的显式初始化
7. 子类的构造函数

此过程中若有父类构造体中调用方法可被子类重载，则JVM会从最低子类对象处寻找此方法，找到则执行，虽然此时对象还未完全生成（可能会造成潜在的错误）。