/* Copyright (c) 2011. Peter Lawrey

*

* "THE BEER-WARE LICENSE" (Revision 128)

* As long as you retain this notice you can do whatever you want with this stuff.

* If we meet some day, and you think this stuff is worth it, you can buy me a beer in return

* There is no warranty.

*/

import java.lang.reflect.Field;

import java.net.URL;

import java.net.URLClassLoader;

public class Main {

public static void main(String... args) throws ClassNotFoundException,

NoSuchFieldException, IllegalAccessException, InterruptedException {

URL url = Main.class.getProtectionDomain().getCodeSource().getLocation();

final String className = Main.class.getPackage().getName()

+ ".UtilityClass";

{

ClassLoader cl;

Class clazz;

for (int i = 0; i < 2; i++) {

cl = new CustomClassLoader(url);

clazz = cl.loadClass(className);

loadClass(clazz);

cl = new CustomClassLoader(url);

clazz = cl.loadClass(className);

loadClass(clazz);

triggerGC();

}

}

triggerGC();

}

private static void triggerGC() throws InterruptedException {

System.out.println("\n-- Starting GC");

System.gc();

Thread.sleep(100);

System.out.println("-- End of GC\n");

}

private static void loadClass(Class clazz) throws NoSuchFieldException,

IllegalAccessException {

final Field id = clazz.getDeclaredField("ID");

id.setAccessible(true);

id.get(null);

}

private static class CustomClassLoader extends URLClassLoader {

public CustomClassLoader(URL url) {

super(new URL[] { url }, null);

}

@Override

protected Class> loadClass(String name, boolean resolve)

throws ClassNotFoundException {

try {

return super.loadClass(name, resolve);

} catch (ClassNotFoundException e) {

return Class.forName(name, resolve, Main.class.getClassLoader());

}

}

@Override

protected void finalize() throws Throwable {

super.finalize();

System.out.println(this.toString() + " - CL Finalized.");

}

}

}

class UtilityClass {

static final String ID = Integer.toHexString(System

.identityHashCode(UtilityClass.class));

private static final Object FINAL = new Object() {

@Override

protected void finalize() throws Throwable {

super.finalize();

System.out.println(ID + " Finalized.");

}

};

static {

System.out.println(ID + " Initialising");

}

}