Java Class Loader dumpClassLoader(ClassLoader cl, PrintWriter out)

Description

dump Class Loader

License

Open Source License

Declaration

public static void dumpClassLoader(ClassLoader cl, PrintWriter out) 

Method Source Code

//package com.java2s;
/*// ww w . ja v  a2 s  .c o  m
 * JBoss, Home of Professional Open Source.
 * Copyright 2006, Red Hat Middleware LLC, and individual contributors
 * as indicated by the @author tags. See the copyright.txt file in the
 * distribution for a full listing of individual contributors.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */

import java.io.PrintWriter;

import java.lang.reflect.Method;
import java.net.URL;

public class Main {
    public static void dumpClassLoader(ClassLoader cl, PrintWriter out) {
        int level = 0;
        while (cl != null) {
            String msg = "Servlet ClassLoader[" + level + "]: " + cl.getClass().getName() + ':' + cl.hashCode();
            out.println(msg);
            URL[] urls = getClassLoaderURLs(cl);
            msg = "  URLs:";
            out.println(msg);
            for (int u = 0; u < urls.length; u++) {
                msg = "  [" + u + "] = " + urls[u];
                out.println(msg);
            }
            cl = cl.getParent();
            level++;
        }
    }

    /** Use reflection to access a URL[] getURLs method so that non-URLClassLoader
     *class loaders that support this method can provide info.
     */
    private static URL[] getClassLoaderURLs(ClassLoader cl) {
        URL[] urls = {};
        try {
            Class returnType = urls.getClass();
            Class[] parameterTypes = {};
            Method getURLs = cl.getClass().getMethod("getURLs", parameterTypes);
            if (returnType.isAssignableFrom(getURLs.getReturnType())) {
                Object[] args = {};
                urls = (URL[]) getURLs.invoke(cl, args);
            }
        } catch (Exception ignore) {
        }
        return urls;
    }
}

Related

1. createClassloader(File libDir, ClassLoader cl)
2. createClassLoader(File root)
3. createClassLoader(final String[] cpEntries)
4. createClassLoader(String fileName)
5. createFallbackClassLoader(Collection files)
6. getClass(Object classLoaderMakedObject, File file, String targetClass)
7. getClassInputStream(String className, ClassLoader cl)
8. getClassLoader()
9. getClassLoader(File[] directories)