Java ClassLoader loadAttachApi()

Description

Loads the com.sun.tools.attach.VirtualMachine class as the entry point to the attach API.

License

Open Source License

Declaration

public static Class loadAttachApi() 

Method Source Code

//package com.java2s;
/*// w ww.  ja v  a2s  . c om
 * Sonar Internals Monitor Plugin
 * Copyright (C) 2012 SonarSource
 * dev@sonar.codehaus.org
 *
 * This program 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 3 of the License, or (at your option) any later version.
 *
 * This program 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 program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02
 */

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

public class Main {
    /**
     * Loads the {@link com.sun.tools.attach.VirtualMachine} class as the entry point to the attach API.
     */
    public static Class loadAttachApi() {
        File toolsJar = locateToolsJar();
        ClassLoader cl = wrapIntoClassLoader(toolsJar);
        try {
            return cl.loadClass("com.sun.tools.attach.VirtualMachine");
        } catch (ClassNotFoundException e) {
            throw new IllegalStateException("Unable to find com.sun.tools.attach.VirtualMachine", e);
        }
    }

    /**
     * Locates the {@code tools.jar} file.
     */
    private static File locateToolsJar() {
        File home = new File(System.getProperty("java.home"));
        return new File(home, "../lib/tools.jar");
    }

    private static ClassLoader wrapIntoClassLoader(File toolsJar) {
        try {
            URL jar = toolsJar.toURI().toURL();
            ClassLoader base = ClassLoader.getSystemClassLoader();
            Method addURL = URLClassLoader.class.getDeclaredMethod("addURL", URL.class);
            addURL.setAccessible(true);
            addURL.invoke(base, jar);
            return base;
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }
}

Related

1. isVMAlive(String procId)
2. load(File propsFile)
3. load(final String filename)
4. load(String propertiesName)
5. load(String propsName)
6. loadCorrectedConfiguration(String configurationFilename)
7. loadFile(String file)
8. loadGuiConfiguration(String configurationFilename)
9. loadProperties(File inFile)