Nelz' Blog

Which Filesystem JAR Is A Class From?

In my environment, a test was blowing up. In my coworkers, it was working fine. On inspection, it seems my environment was expecting a different version of a class. How do I figure out what JAR the new/incorrect requirements are coming from?

I found this blog post, and it helped me greatly: From which Jar a Class was loaded?

I used this info to write the following utility:

package net.nelz.utils;

import javax.activation.*;
import java.security.*;
import java.net.*;

public class ClassFinder {
	public static String findClassOnFilesystem(final String className) {
		try {
			final Class clazz = Thread.currentThread().getContextClassLoader().loadClass(className);
			return ClassFinder.findClassOnFilesystem(clazz);
		} catch (ClassNotFoundException ex) {
			return "Class:" + className + " - CLASS NOT FOUND!";
		}
	}

	public static String findClassOnFilesystem(final Class clazz) {
		final ProtectionDomain pDomain = clazz.getProtectionDomain();
		final CodeSource cSource = pDomain.getCodeSource();
		final URL loc = cSource.getLocation();
		final String result = clazz.toString() + " - " + loc;
		System.out.println(result);
		return result;
	}
}

Additionally, after finding this solution, a coworker pointed me to the Dependency Finder as another tool that can help diagnose classpath issues.

Posted at 02:04PM Apr 10, 2008 by Nelson "Nelz" Carpentier in Java  |  Comments[0]