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== Get the path from where a class is loaded ==



<source lang="java">
public class Main {
public static void main(String[] args) {
Main csl = new Main();
csl.getCodeSourceLocation();
}
private void getCodeSourceLocation() {
System.out.println("Code source location: "
+ getClass().getProtectionDomain().getCodeSource().getLocation());
}
}</source>



== Loading a Class That Is Not on the Classpath ==



<source lang="java">
A URLClassLoader can be used to load classes in any directory.
import java.io.File;
import java.net.URL;
import java.net.URLClassLoader;
public class Main {
public static void main(String[] argv) throws Exception {
File file = new File("c:\\");
URL url = file.toURI().toURL();
URL[] urls = new URL[] { url };
ClassLoader cl = new URLClassLoader(urls);
Class cls = cl.loadClass("com.mycompany.MyClass");
}
}</source>



== Load the class source location from Class.getResource() ==



<source lang="java">
public class Main {
public static void main(String args[]) {
Class theClass = Main.class;
java.net.URL u = theClass.getResource("");
System.out.println("This class (FromWhere) is located at : " + u);
}
}</source>



== Obtain from where a Class is loaded ==



<source lang="java">
public class Main {
public static void main(String args[]) {
Main m = new Main();
System.out.println(m.getClass().getName() + " is loaded from "
+ m.getClass().getProtectionDomain().getCodeSource().getLocation());
}
}</source>



== Returns a reference to a file with the specified name that is located somewhere on the classpath. ==



<source lang="java">
/*
* JCommon : a free general purpose class library for the Java(tm) platform
*
*
* (C) Copyright 2000-2005, by Object Refinery Limited and Contributors.
*
* Project Info: http://www.jfree.org/jcommon/index.html
*
* This library 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 library 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 library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
* USA.
*
* [Java is a trademark or registered trademark of Sun Microsystems, Inc.
* in the United States and other countries.]
*
* ------------------
* FileUtilities.java
* ------------------
* (C) Copyright 2000-2004, by Object Refinery Limited.
*
* Original Author: David Gilbert (for Object Refinery Limited);
* Contributor(s): -;
*
* $Id: FileUtilities.java,v 1.5 2005/10/18 13:16:02 mungady Exp $
*
* Changes (from 5-Nov-2001)
* -------------------------
* 05-Nov-2001 : Changed package to com.jrefinery.io.* (DG);
* 04-Mar-2002 : Renamed Files.java --> FileUtilities.java (DG);
* 10-Oct-2002 : Fixed errors reported by Checkstyle (DG);
*
*/
import java.io.File;
import java.util.StringTokenizer;
/**
* A class containing useful utility methods relating to files.
*
* @author David Gilbert
*/
public class FileUtilities {
/**
* Returns a reference to a file with the specified name that is located
* somewhere on the classpath. The code for this method is an adaptation of
* code supplied by Dave Postill.
*
* @param name
* the filename.
*
* @return a reference to a file or <code>null</code> if no file could be
* found.
*/
public static File findFileOnClassPath(final String name) {
final String classpath = System.getProperty("java.class.path");
final String pathSeparator = System.getProperty("path.separator");
final StringTokenizer tokenizer = new StringTokenizer(classpath, pathSeparator);
while (tokenizer.hasMoreTokens()) {
final String pathElement = tokenizer.nextToken();
final File directoryOrJar = new File(pathElement);
final File absoluteDirectoryOrJar = directoryOrJar.getAbsoluteFile();
if (absoluteDirectoryOrJar.isFile()) {
final File target = new File(absoluteDirectoryOrJar.getParent(), name);
if (target.exists()) {
return target;
}
} else {
final File target = new File(directoryOrJar, name);
if (target.exists()) {
return target;
}
}
}
return null;
}
}</source>

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