Java继承与初始化

code

public class TestClassInitial {
public static void main(String[] args){
Beetle b=new Beetle();
}
}

class Insect{
private int i=9;
protected int j;
Insect(){
System.out.println("i="+i+", j="+j);
j=39;
}
{
System.out.println("  insect");

}
private static int x1=printStatic("static Insect.x1 init");
static{
System.out.println(" static insect");
}
public static int printStatic(String string) {
// TODO Auto-generated method stub
System.out.println(string);
return 1;
}
}
class Beetle extends Insect{
private String k="k";
static{
System.out.println("static Beetle");
}
{
System.out.println("Beetle");
}
public Beetle(){
System.out.println("construct Beetle");
}
private static int x2=Insect.printStatic("beetle x2");
}

总结流程：

加载main所在方法类

如果该类有基类，则加载基类，持续下去

反过来一个个加载static修饰的成员变量或者代码块 顺序从上到下

从基类开始，一次次加载非静态成员，一个类中从上到下，然后到初始化构造函数

子类加载非静态成员，然后构造函数

动态代码快在构造函数之前发生

运行结果

static Insect.x1 init
static insect
static Beetle
beetle x2
insect
i=9, j=0
Beetle
construct Beetle