Find a Class in Jars

I often have to find a class (or its different occurrences) in a list of jars located in a folder (or its sub-folders). The Jython script below parses all the jars in a location, and display the name of all the jars containing the class I’m looking for. Stick it into a file called “”

import os, sys, traceback
from os.path import isdir,join
from import *
from java.util.jar import *
from import *

def scan_directory(class_name, directory=’.’): for f in os.listdir(directory): if os.path.isdir(join(directory, f)): scan_directory(class_name, join(directory, f)) if os.path.basename(f).lower().endswith(’.jar’) > 0 \ and not os.path.isdir(join(directory, f)): scan_jar(class_name, join(directory, f))

def scan_jar(class_name, jar_file): try: jar = JarFile(jar_file) entries = jar.entries() while entries.hasMoreElements(): entry = entries.nextElement() if entry.toString().find(class_name) >= 0: print ‘%s: %s’ \ % (os.path.abspath(jar_file), entry)

except ZipException: print ‘Error trying to open %s’ % jar_file traceback.print_exc(file=sys.stdout)

if name '__main__': if not len(sys.argv) 3: print “Usage: jython “ sys.exit(1) scan_directory(sys.argv[1] + '.class', sys.argv[2])

It can be called as follows:

jython MyNiceStub C:\application_server\lib

This script is quite handy when investigating issues related to ClassNotFoundException, or ClassCastException, or classloading-related problems. Watch out, the script appends “.class” to the name of the class you’re passing to the script, so if you’re looking for something other than a class (a resource file, for example), it won’t find it. It doesn’t look for classes which are not in jars either – but adding this to the script is trivial!