一道关于ClassLoader的面试题

import java.net.*;



public class Andromeda {

	private static final Andromeda instance = new Andromeda();

	

	private Andromeda(){

		

	}

	

	public static Andromeda getInstance(){

		return instance;

	}

	

	public static void main(String[] args) throws Exception{

		

		URLClassLoader loader1 = new URLClassLoader(new URL[]{new URL("file:///home/root/workspace/andromeda/bin/")}){

			public String toString(){

				return "loader1";

			}

		};

		

		URLClassLoader loader2 = new URLClassLoader(new URL[]{new URL("file:///home/root/workspace/andromeda/bin/")}, 

				ClassLoader.getSystemClassLoader().getParent()){

			public String toString(){

				return "loader2";

			}

		};



		Class clazz1 = loader1.loadClass("Andromeda");

		Class clazz2 = loader2.loadClass("Andromeda");

		

		Andromeda obj1 = (Andromeda)(clazz1.getDeclaredMethod("getInstance", new Class[0]).invoke(null, new Object[0]));

		System.out.println(loader1 + " loads " + obj1);

		

		Andromeda obj2 = (Andromeda)(clazz2.getDeclaredMethod("getInstance", new Class[0]).invoke(null, new Object[0]));

		System.out.println(loader2 + " loads " + obj2);

		

		Andromeda obj3 = Andromeda.getInstance();

		System.out.println(Andromeda.class.getClassLoader() + " loads " + obj3);

	}

}