jvm classloader知识

1. jvm classloader 分

bootstrap classloader

system classloader

extention classloader

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package com.jason.jvm;import java.net.URL;public class JvmClassLoaderDemo {/** * bootstrap classloader */public void bootstrap(){URL[] urls=sun.misc.Launcher.getBootstrapClassPath().getURLs();for (int i = 0; i < urls.length; i++) {System.out.println(urls[i].toExternalForm());}}/** * extention classloader */public void extention(){System.out.println(System.getProperty("java.ext.dirs"));ClassLoader extensionClassloader=ClassLoader.getSystemClassLoader().getParent();System.out.println("the parent of extension classloader : "+extensionClassloader.getParent());}/** * system classloader */public void system(){System.out.println(System.getProperty("java.class.path"));}/** * @param args */public static void main(String[] args) {// TODO Auto-generated method stubJvmClassLoaderDemo a = new JvmClassLoaderDemo();System.out.println("**********bootstrap begin************");a.bootstrap();System.out.println("**********bootstrap end************");System.out.println("**********extention begin************");a.extention();System.out.println("**********extention end************");System.out.println("**********system begin************");a.system();System.out.println("**********system end************");}}