How should I load Jars dynamically at runtime?

URLClassLoader child = new URLClassLoader (myJar.toURL(), this.getClass().getClassLoader());
Class classToLoad = Class.forName ("com.MyClass", true, child);
Method method = classToLoad.getDeclaredMethod ("myMethod");
Object instance = classToLoad.newInstance ();
Object result = method.invoke (instance);

public class ClassPathHack {
    private static final Class[] parameters = new Class[] {URL.class};

    public static void addFile(String s) throws IOException
    {
        File f = new File(s);
        addFile(f);
    }

    public static void addFile(File f) throws IOException
    {
        //f.toURL is deprecated
        addURL(f.toURL());
    }

    public static void addURL(URL u) throws IOException
    {
        URLClassLoader sysloader = (URLClassLoader) ClassLoader.getSystemClassLoader();
        Class sysclass = URLClassLoader.class;

        try {
            Method method = sysclass.getDeclaredMethod("addURL", parameters);
            method.setAccessible(true);
            method.invoke(sysloader, new Object[] {u});
        } catch (Throwable t) {
            t.printStackTrace();
            throw new IOException("Error, could not add URL to system classloader");
        }

    }
}

JarClassLoader jcl = new JarClassLoader();
jcl.add("myjar.jar"); //Load jar file
jcl.add(new URL("http://myserver.com/myjar.jar")); //Load jar from a URL
jcl.add(new FileInputStream("myotherjar.jar")); //Load jar file from stream
jcl.add("myclassfolder/"); //Load class folder
jcl.add("myjarlib/"); //Recursively load all jar files in the folder/sub-folder(s)

JclObjectFactory factory = JclObjectFactory.getInstance();

//Create object of loaded class
Object obj = factory.create(jcl,"mypackage.MyClass");

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 * Copyright (c) 2004, Federal University of So Carlos                                           *
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 *     * without specific prior written permission.                                               *
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/*
 * Created on Oct 6, 2004
 */
package tools;

import java.io.File;
import java.io.IOException;
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.net.URL;
import java.net.URLClassLoader;

/**
 * Useful class for dynamically changing the classpath, adding classes during runtime.
 * @author unknown
 */
public class ClasspathHacker {
    /**
     * Parameters of the method to add an URL to the System classes.
     */
    private static final Class<?>[] parameters = new Class[]{URL.class};

    /**
     * Adds a file to the classpath.
     * @param s a String pointing to the file
     * @throws IOException
     */
    public static void addFile(String s) throws IOException {
        File f = new File(s);
        addFile(f);
    }//end method

    /**
     * Adds a file to the classpath
     * @param f the file to be added
     * @throws IOException
     */
    public static void addFile(File f) throws IOException {
        addURL(f.toURI().toURL());
    }//end method

    /**
     * Adds the content pointed by the URL to the classpath.
     * @param u the URL pointing to the content to be added
     * @throws IOException
     */
    public static void addURL(URL u) throws IOException {
        URLClassLoader sysloader = (URLClassLoader)ClassLoader.getSystemClassLoader();
        Class<?> sysclass = URLClassLoader.class;
        try {
            Method method = sysclass.getDeclaredMethod("addURL",parameters);
            method.setAccessible(true);
            method.invoke(sysloader,new Object[]{ u });
        } catch (Throwable t) {
            t.printStackTrace();
            throw new IOException("Error, could not add URL to system classloader");
        }//end try catch
    }//end method

    public static void main(String args[]) throws IOException, SecurityException, ClassNotFoundException, IllegalArgumentException, InstantiationException, IllegalAccessException, InvocationTargetException, NoSuchMethodException{
        addFile("C:\dynamicloading.jar");
        Constructor<?> cs = ClassLoader.getSystemClassLoader().loadClass("test.DymamicLoadingTest").getConstructor(String.class);
        DymamicLoadingTest instance = (DymamicLoadingTest)cs.newInstance();
        instance.test();

    }
}

public void initialize(String libDir) throws Exception {
File dependencyDirectory = new File(libDir);
File[] files = dependencyDirectory.listFiles();
ArrayList<URL> urls = new ArrayList<URL>();
for (int i = 0; i < files.length; i++) {
    if (files[i].getName().endsWith(".jar")) {
	urls.add(files[i].toURL());
	//urls.add(files[i].toURI().toURL());
    }
}
classLoader = new JarFileClassLoader("Scheduler CL" + System.currentTimeMillis(),
	urls.toArray(new URL[urls.size()]),
	GFClassLoader.class.getClassLoader());
}