Loading an entire JAR via a classloader

Question

Hi how would I load an entire JAR file via a classloader. Currently I'm able to load one file at a time (in this case org.w3c.dom.Node) as shown below:
import java.net.*;
public class MyJarLoader {
   public static void main(String [] args) throws Exception {
     URL[] urlsToLoadFrom = new URL[]{new URL("file:subdir3/xml-apis.jar")};
     URLClassLoader loader1 = new URLClassLoader(urlsToLoadFrom);
     Class cls1 = Class.forName("org.w3c.dom.Node", true, loader1);
     System.out.println("Loaded '"+cls1.getName()+"'");
     org.w3c.dom.Node Node = (org.w3c.dom.Node) cls1.newInstance();
Thanks

Answer 1

Figured this one out as below. Note this is the simplistic solution since it requires that the jar files be present in the classpath. If not, you will have to write your own loadClass method to read the data from the zip (& then can't use the method 'Class.forName()').
Regards
//Load Apache JAR files
URL[] urlArrToLoadFrom = new URL[]{new URL("file:xalan-j_2_5_0/xml-apis.jar"),
            new URL("file:xalan-j_2_5_0/xercesImpl.jar"), new URL("file:xalan-j_2_5_0/xalan.jar")};
//Create a URLClassLoader to access jar files
URLClassLoader urlLoaderGeneric = new URLClassLoader(urlArrToLoadFrom);
//Foreach jar file, open, load class files & close
for(int i=0; i<urlArrToLoadFrom.length; i++) {
//Debug
   System.out.println(urlArrToLoadFrom.toString());
   //Open zip file
   ZipFile zf = new ZipFile(urlArrToLoadFrom[i].getFile());
   for (Enumeration enum = zf.entries(); enum.hasMoreElements();) {
     //Get entry
     ZipEntry ze = (ZipEntry) enum.nextElement();
     //Only load if it's not a directory and it's a class file
     int iIndexClass = -1;
     if (!ze.isDirectory() && ((iIndexClass = ze.getName().indexOf(".class")) != -1)) {
         //Remove .class & replace / with .
         String strApacheClassName = (ze.getName().substring(0,iIndexClass)).replace('/','.');
         //Load class file
         Class classApache = Class.forName(strApacheClassName, true, urlLoaderGeneric);
         System.out.println("Loaded '"+classApache.getName()+"'");
   //Close zip
   zf.close();