Snippet : Where.java

import java.net.URL;
import java.security.CodeSource;
/**
 * Find out where a class on the classpath will be loaded from.
 * Fully qualified classname goes on the command line.
 */
public class Where
 {
 /**
 * main
 * @param args name of fully qualified class to find, using dots, but no dot class.
 * e.g. java.exe Where javax.mail.internet.MimeMessage
 */
 public static void main ( String[] args )
 {
 try
 {
 String qualifiedClassName = args[0];
 Class qc = Class.forName( qualifiedClassName );
 CodeSource source = qc.getProtectionDomain().getCodeSource();
 if ( source != null )
 {
 URL location = source.getLocation();
 out.println ( qualifiedClassName + " : " + location );
 }
 else
 {
 out.println ( qualifiedClassName + " : " + "unknown source, likely rt.jar" );
 }
 }
 catch ( Exception e )
 {
 err.println( "Unable to locate class on command line." );
 e.printStackTrace();
 }
 }
 }