Resolving the "Not all jars signed with same certificate" issue

Almost a year ago I wrote posting on how to resolve the "Not all jars signed with the same certificate" problem encountered from time to time with signed Web Start applications.   My solution at that time was to use a short Groovy script to show each jar and a list of the certificates the jar was signed with.  For those familiar with Groovy, that's still my suggestion.

Recently one of our customer service folks was fighting this same problem at a customer site.  To make matters worse, they were not familiar with Groovy, so using my previous script was not an option.   I decided to bite the bullet and write the Java equivalent.

Below is my Java-equivalent of the Groovy script.  The code is saved as the JarSigners project at GitHub.

package util;

import java.io.File;
import java.io.FilenameFilter;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.zip.ZipEntry;
import java.util.zip.ZipException;
import java.util.zip.ZipFile;

/**
 *  Show which jars are signed with which code signing certificates
 */
public class JarSigners {

 private String folderName;
 private Map> map;
 private Set certs;
 
 public JarSigners(String folderName) {
  this.folderName = folderName;
  map = new HashMap>();
  certs = new HashSet();
 }
 
 public void listJarSigners() throws ZipException, IOException {
  File dir = new File(folderName);
  FilenameFilter filter = new FilenameFilter() {
      public boolean accept(File dir, String name) {
          return name.endsWith(".jar");
      }
  };
  String[] files = dir.list(filter);
  System.out.println("Found "+files.length+" files in folder: "+folderName);
  for (String fileName : files) {
   checkJarForCertificate(fileName);
  }
  System.out.println("Certificates used to sign the jars: "+certs);
  if (certs.size() > 1) {
   System.out.println("WARNING: More that one certificate shows up in the jars!");
  }
  System.out.println("Details jar->certificate: "+map);
 }
 
 private void checkJarForCertificate(String fileName) throws ZipException, IOException {
  File jar = new File(folderName, fileName);
  ZipFile zip = new ZipFile(jar);
  //System.out.println("Processing "+fileName);
  for (Enumeration entries = zip.entries(); entries.hasMoreElements();) {
         // Get the entry name
         String zipEntryName = ((ZipEntry)entries.nextElement()).getName();
         if (zipEntryName.endsWith(".RSA")) {
          if (!certs.contains(zipEntryName)) {
           certs.add(zipEntryName);
          }
          if (map.containsKey(fileName)) {
           List list = map.get(zipEntryName);
           list.add(zipEntryName);
          } else {
           List list = new ArrayList();
           list.add(zipEntryName);
           map.put(fileName, list);
          }
         }
     }
  zip.close();
  
 }

 /**
  * @param args
  * @throws IOException 
  * @throws ZipException 
  */
 public static void main(String[] args) throws ZipException, IOException {
  if (args.length != 1) {
   System.out.println("Invalid invocation: you must pass a folder name");
   return;
  }
  JarSigners js = new JarSigners(args[0]);
  js.listJarSigners();
  System.out.println("Done!");
 }

}

Hope this helps!