Java中类初始化代码块和父类构造器执行顺序问题,

Answer 1

I searched for a long time but couldn’t find the execution time of the block. Later, I used javap -c to check the class file and found that the block was thrown into the constructor, and the <init> method of invokespecial superclass was also in it, but it was in front of the block, so this Explained your problem.

Answer 2

First of all, after using the javac command to compile a java class, the initialization code block of the java class will disappear - the code in the initialization code block will be "restored" to each constructor and will be located in front of all the code in the constructor.

Basic process:

1.为要创建的对象分配内存空间，其大小取决于Java类及其父类和祖先类包含的所有实例域的数量和类型
2.如果内存分配成功(失败会抛出OutOfMemoryError错误)，把新创建的对象的所有实例域(包括父类的)都设为默认值
3.调用构造方法
    ①调用父类的构造方法，如果没有显式使用super关键字进行调用，则由编译器自动生成相关的代码
    ②按照类中实例域的顺序初始化实例域的值
    ③执行类的构造方法中的其他代码完成最终的初始化工作

You can analyze it yourself.