对象初始化（静态代码块、构造函数、构造代码块执行顺序）

举例：

package com.md.test;

public class Test02 {
    static{
        System.out.println("public类的static 代码块。");
        j = 10;
    }
    private static int j;

    public static void main(String[] args) {
        System.out.println("====父类A====");
        new A();
        System.out.println(new A());
        System.out.println("=====子类B=====");
        new B();
        System.out.println("=====父类A=====");
        new A();
    }
}
class A{
    public A(){
        System.out.println("我是父类的无参构造");
    }
    {
        System.out.println("我是父类的构造代码块");
        int i = 10;
    }
    static {
        System.out.println("我是父类的静态代码块");
    }
    public void qaq(){
        System.out.println("我是父类的普通方法");
    }
}
class B extends A{
    public B(){
        System.out.println("我是子类的无参构造");
    }
    {
        System.out.println("我是子类的构造代码块");
    }
    static {
        System.out.println("我是子类的静态代码块");
    }

}

Console：

"C:Program FilesJavajdk1.8.0_301binjava.exe" "-javaagent:D:下载电脑应用IntelliJ IDEA 2021.2.1libidea_rt.jar=64685:D:下载电脑应用IntelliJ IDEA 2021.2.1bin" -Dfile.encoding=UTF-8 -classpath "C:Program FilesJavajdk1.8.0_301jrelibcharsets.jar;C:Program FilesJavajdk1.8.0_301jrelibdeploy.jar;C:Program FilesJavajdk1.8.0_301jrelibextaccess-bridge-64.jar;C:Program FilesJavajdk1.8.0_301jrelibextcldrdata.jar;C:Program FilesJavajdk1.8.0_301jrelibextdnsns.jar;C:Program FilesJavajdk1.8.0_301jrelibextjaccess.jar;C:Program FilesJavajdk1.8.0_301jrelibextjfxrt.jar;C:Program FilesJavajdk1.8.0_301jrelibextlocaledata.jar;C:Program FilesJavajdk1.8.0_301jrelibextnashorn.jar;C:Program FilesJavajdk1.8.0_301jrelibextsunec.jar;C:Program FilesJavajdk1.8.0_301jrelibextsunjce_provider.jar;C:Program FilesJavajdk1.8.0_301jrelibextsunmscapi.jar;C:Program FilesJavajdk1.8.0_301jrelibextsunpkcs11.jar;C:Program FilesJavajdk1.8.0_301jrelibextzipfs.jar;C:Program FilesJavajdk1.8.0_301jrelibjavaws.jar;C:Program FilesJavajdk1.8.0_301jrelibjce.jar;C:Program FilesJavajdk1.8.0_301jrelibjfr.jar;C:Program FilesJavajdk1.8.0_301jrelibjfxswt.jar;C:Program FilesJavajdk1.8.0_301jrelibjsse.jar;C:Program FilesJavajdk1.8.0_301jrelibmanagement-agent.jar;C:Program FilesJavajdk1.8.0_301jrelibplugin.jar;C:Program FilesJavajdk1.8.0_301jrelibresources.jar;C:Program FilesJavajdk1.8.0_301jrelibrt.jar;E:IDEAStudy every DayDay03targetclasses;E:apache-maven-3.8.1-binStudyorgspringframeworkbootspring-boot-starter2.4.1spring-boot-starter-2.4.1.jar;E:apache-maven-3.8.1-binStudyorgspringframeworkbootspring-boot2.4.1spring-boot-2.4.1.jar;E:apache-maven-3.8.1-binStudyorgspringframeworkspring-context5.3.2spring-context-5.3.2.jar;E:apache-maven-3.8.1-binStudyorgspringframeworkspring-aop5.3.2spring-aop-5.3.2.jar;E:apache-maven-3.8.1-binStudyorgspringframeworkspring-beans5.3.2spring-beans-5.3.2.jar;E:apache-maven-3.8.1-binStudyorgspringframeworkspring-expression5.3.2spring-expression-5.3.2.jar;E:apache-maven-3.8.1-binStudyorgspringframeworkbootspring-boot-autoconfigure2.4.1spring-boot-autoconfigure-2.4.1.jar;E:apache-maven-3.8.1-binStudyorgspringframeworkbootspring-boot-starter-logging2.4.1spring-boot-starter-logging-2.4.1.jar;E:apache-maven-3.8.1-binStudychqoslogbacklogback-classic1.2.3logback-classic-1.2.3.jar;E:apache-maven-3.8.1-binStudychqoslogbacklogback-core1.2.3logback-core-1.2.3.jar;E:apache-maven-3.8.1-binStudyorgapachelogginglog4jlog4j-to-slf4j2.13.3log4j-to-slf4j-2.13.3.jar;E:apache-maven-3.8.1-binStudyorgapachelogginglog4jlog4j-api2.13.3log4j-api-2.13.3.jar;E:apache-maven-3.8.1-binStudyorgslf4jjul-to-slf4j1.7.30jul-to-slf4j-1.7.30.jar;E:apache-maven-3.8.1-binStudyjakartaannotationjakarta.annotation-api1.3.5jakarta.annotation-api-1.3.5.jar;E:apache-maven-3.8.1-binStudyorgspringframeworkspring-core5.3.2spring-core-5.3.2.jar;E:apache-maven-3.8.1-binStudyorgspringframeworkspring-jcl5.3.2spring-jcl-5.3.2.jar;E:apache-maven-3.8.1-binStudyorgyamlsnakeyaml1.27snakeyaml-1.27.jar;E:apache-maven-3.8.1-binStudyorgslf4jslf4j-api1.7.30slf4j-api-1.7.30.jar" com.md.test.Test02
public类的static 代码块。
====父类A====
我是父类的静态代码块
我是父类的构造代码块
我是父类的无参构造
=====子类B=====
我是子类的静态代码块
我是父类的构造代码块
我是父类的无参构造
我是子类的构造代码块
我是子类的无参构造
=====父类A=====
我是父类的构造代码块
我是父类的无参构造

Process finished with exit code 0

总结：静态资源>代码块>构造函数>普通方法。    子类继承父类后，调用子类会先执行子类继承父类的功能，然后才会执行子类自己的功能。