ImageIcon not loading from Jar file

Question

Hi,
I'm developing an application that uses ImageIcons in JButtons.
The images are stored in the following relative dir:
images/<filename>.jpg
They load fine when I run the application from class files in the appropriate directory.
However when I jar everything, my ImageIcons don't load.
I know that my jar file is in the classpath, because other items in the jar file load successfully.
I've tried everything the related threads recommend, but still nothing.
When I try to launch from the jar file, the ClassLoader.getResource("filepath"); returns null.
Whereas when I launch the class files, it returns the correct URL for the image.
What am I missing? Is this jar file security-related? Do I need to sign the jar file with all-permissions?
Any suggestions would be gratefully appreciated.
I'm using java 1.4.2_01-b06
Much thanks,
-Jeroen

Answer 1

Here is a little load program that you can use.
import java.io.*;
import java.util.*;
import java.util.zip.*;
* <p>Resources extracts all the resources from a jar file into binary large
* objects. These objects can be used to create images or read as streams.
* This class is implemented as a singleton model.</p>
* <p>An attempt is made to find the path to the jar file in
* if this file is not found no resources are
* loaded.
* @author Michael Couck
* @version 1.00, 16/01/2004
public final class Resources extends Constants {
      * The only instance of this class
     private static Resources resources;
      * Hashtables for the sizes of the entries in the jar
     private static Hashtable sizes= new Hashtable();
      * Hashtable for each entry in the jar as a blob
     private static Hashtable contents= new Hashtable();
      * Flag to test if the resources were loaded correctly
     private static boolean resourcesLoaded= false;
      * Initilises the <code>static</code> instance of the
      * <code>Resources</code> instance.
     public static void initiliseResources() {
          if (resources == null)
               resources= new Resources();
      * Instanciates a <code>Resources</code> object.
     private Resources() {
          init();
      * Returns a resource as a <code>byte</code> array, which can then be used
      * as a <code>ByteArrayInputStream</code> to instanciate among other things
      * images and property files.
      * @param name a resource name. This is the path to the recource from the
      *         root of the jar file.
     public static byte[] getResourceAsByteArray(String name) {
          if (resources == null)
               resources= new Resources();
          return (byte[]) Resources.contents.get(name);
      * Returns true if the resources were correctly loaded
     public static boolean resourcesLoaded() {
          return resourcesLoaded;
      * Reads the jar file and inserts the contents
      * into the Hashtables.
     public void init() {
          try {
               //Sizes into the table     
                                                                File jar= new File("[path to]/yourjar.jar");
               if (jar != null && jar.exists()) {
                    //Found the path to this jar file
                    ZipFile zipFile= new ZipFile(jar);
                    Enumeration enum= zipFile.entries();
                    while (enum.hasMoreElements()) {
                         ZipEntry zipEntry= (ZipEntry) enum.nextElement();
                         sizes.put(
                              zipEntry.getName(),
                              new Integer((int) zipEntry.getSize()));
                    zipFile.close();
                    //Contents into the table
                    FileInputStream fis= new FileInputStream(jar);
                    BufferedInputStream bis= new BufferedInputStream(fis);
                    ZipInputStream zis= new ZipInputStream(bis);
                    ZipEntry zipEntry= null;
                    while ((zipEntry= zis.getNextEntry()) != null) {
                         if (zipEntry.isDirectory()) {
                              continue;
                         int size= (int) zipEntry.getSize();
                         // -1 means unknown size.
                         if (size == -1) {
                              size=
                                   ((Integer) sizes.get(zipEntry.getName()))
                                        .intValue();
                         byte[] blob= new byte[(int) size];
                         int readBuffer= 0;
                         int buffer= 0;
                         while (((int) size - readBuffer) > 0) {
                              buffer=
                                   zis.read(blob, readBuffer, (int) size - readBuffer);
                              if (buffer == -1) {
                                   break;
                              readBuffer += buffer;
                         contents.put(zipEntry.getName(), blob);
                    resourcesLoaded= true;
          } catch (NullPointerException e) {
               Constants.logger.severe(e.getMessage());
               StackTraceElement[] stackTrace= e.getStackTrace();
               for (int i= 0; i < stackTrace.length; i++) {
                    Constants.logger.severe(stackTrace.toString());
               resourcesLoaded= false;
          } catch (FileNotFoundException e) {
               Constants.logger.severe(e.getMessage());
               StackTraceElement[] stackTrace= e.getStackTrace();
               for (int i= 0; i < stackTrace.length; i++) {
                    Constants.logger.severe(stackTrace[i].toString());
               resourcesLoaded= false;
          } catch (IOException e) {
               Constants.logger.severe(e.getMessage());
               StackTraceElement[] stackTrace= e.getStackTrace();
               for (int i= 0; i < stackTrace.length; i++) {
                    Constants.logger.severe(stackTrace[i].toString());
               resourcesLoaded= false;
} //End Resources
You can get the icons with "new ImageIcon(new ByteArrayResources.getResourceAsByteArray(String name));
See ya
Michael