类加载器

类加载器的作用

package com.guo.reflection;

public class Test07 {
    public static void main(String[] args) throws ClassNotFoundException {

        //获取系统类的加载器
        ClassLoader systemClassLoader = ClassLoader.getSystemClassLoader();
        System.out.println(systemClassLoader);    //sun.misc.Launcher$AppClassLoader@18b4aac2

        //获取系统类的加载器的父类加载器---->扩展类加载器
        ClassLoader parent = systemClassLoader.getParent();
        System.out.println(parent);    //sun.misc.Launcher$ExtClassLoader@1b6d3586

        //获取扩展类加载器的父类加载器---->根加载器(c/c++)
        ClassLoader parent1 = parent.getParent();
        System.out.println(parent1);    //null

        //测试当前类是那个加载器加载的
        ClassLoader classLoader = Class.forName("com.guo.reflection.Test07").getClassLoader();
        System.out.println(classLoader);    //sun.misc.Launcher$AppClassLoader@18b4aac2


        //测试JDK内置的类是那个加载器加载的
        classLoader = Class.forName("java.lang.Object").getClassLoader();
        System.out.println(classLoader);    //null


        //如何获得系统类加载器可以加载的路径
        System.out.println(System.getProperty("java.class.path"));

                //双亲委派机制--->安全性
                    //java.lang.String--->

        /*
            D:\environment\java\jdk1.8\jre\lib\charsets.jar;
            D:\environment\java\jdk1.8\jre\lib\deploy.jar;
            D:\environment\java\jdk1.8\jre\lib\ext\access-bridge-64.jar;
            D:\environment\java\jdk1.8\jre\lib\ext\cldrdata.jar;
            D:\environment\java\jdk1.8\jre\lib\ext\dnsns.jar;
            D:\environment\java\jdk1.8\jre\lib\ext\jaccess.jar;
            D:\environment\java\jdk1.8\jre\lib\ext\jfxrt.jar;
            D:\environment\java\jdk1.8\jre\lib\ext\localedata.jar;
            D:\environment\java\jdk1.8\jre\lib\ext\nashorn.jar;
            D:\environment\java\jdk1.8\jre\lib\ext\sunec.jar;
            D:\environment\java\jdk1.8\jre\lib\ext\sunjce_provider.jar;
            D:\environment\java\jdk1.8\jre\lib\ext\sunmscapi.jar;
            D:\environment\java\jdk1.8\jre\lib\ext\sunpkcs11.jar;
            D:\environment\java\jdk1.8\jre\lib\ext\zipfs.jar;
            D:\environment\java\jdk1.8\jre\lib\javaws.jar;
            D:\environment\java\jdk1.8\jre\lib\jce.jar;
            D:\environment\java\jdk1.8\jre\lib\jfr.jar;
            D:\environment\java\jdk1.8\jre\lib\jfxswt.jar;
            D:\environment\java\jdk1.8\jre\lib\jsse.jar;
            D:\environment\java\jdk1.8\jre\lib\management-agent.jar;
            D:\environment\java\jdk1.8\jre\lib\plugin.jar;
            D:\environment\java\jdk1.8\jre\lib\resources.jar;
            D:\environment\java\jdk1.8\jre\lib\rt.jar;
            C:\Users\cheng\Desktop\code\Annotation and Reflection\out\production\Annotation and Reflection;
            D:\software\IntelliJ IDEA 2025.3.3\lib\idea_rt.jar
        */


    }
}