package org.jboss.book.jmx.ex0;import java.io.File;import java.net.URL;import java.net.URLClassLoader;import java.lang.reflect.Method;import org.apache.log4j.Logger;import org.jboss.util.ChapterExRepository;import org.jboss.util.Debug;/** An example of IllegalAccessExceptions due to classes loaded by two class * loaders. * @author Scott.Stark@jboss.org * @version $Revision: 1.1 $ */public class ExIAEd{   public static void main(String[] args) throws Exception   {      ChapterExRepository.init(ExIAEd.class);      String chapDir = System.getProperty("chapter.dir");      Logger ucl0Log = Logger.getLogger("UCL0");      File jar0 = new File(chapDir+"/j0.jar");      ucl0Log.info("jar0 path: "+jar0.toString());      URL[] cp0 = {jar0.toURL()};      URLClassLoader ucl0 = new URLClassLoader(cp0);      Thread.currentThread().setContextClassLoader(ucl0);      StringBuffer buffer = new StringBuffer("ExIAEd Info");      Debug.displayClassInfo(ExIAEd.class, buffer, false);      ucl0Log.info(buffer.toString());      Class ctxClass1 = ucl0.loadClass("org.jboss.book.jmx.ex0.ExCtx");      buffer.setLength(0);      buffer.append("ExCtx Info");      Debug.displayClassInfo(ctxClass1, buffer, false);      ucl0Log.info(buffer.toString());      Object ctx0 = ctxClass1.newInstance();      try      {         Class[] types = {Object.class};         Method useValue = ctxClass1.getDeclaredMethod("pkgUseValue", types);         Object[] margs = {null};         useValue.invoke(ctx0, margs);      }      catch(Exception e)      {         ucl0Log.error("Failed to invoke ExCtx.pkgUseValue", e);      }   }}