I've got a kuhl application that among other things, for a demo,
flashes pictures, meant to look like a top-down view of a map,
based on two image data sets stored in the jar file. The call to
find them, and alternate them in a JPanel is done like this:

 public void actionPerformed(ActionEvent ae)
 {
   java.net.URL imgURL;

   if ( ae.getSource() ==

EvwfConstantButtons.buttonElementArray[EvwfConstantButtons.PBC_REFRESH_MAP_BUTTON])
   {

     if ( maptoggle )
     {
       imgURL = EvwfUtilities.class.getResource
       (
         "images/EvwfSampleMap1.png" // FIXME Obviously we don't want
this hard wired
       );
     }
     else
     {
       imgURL = EvwfUtilities.class.getResource
       (
         "images/EvwfSampleMap2.png" // FIXME Obviously we don't want
this hard wired
       );
     }

     maptoggle = maptoggle ? false : true ;

     Image img = getToolkit().getImage(imgURL);

     System.err.print( "Refreshed Map URL is: " + imgURL.toString() +
"\n" );
     try {
         MediaTracker tracker = new MediaTracker(this);
         tracker.addImage(img, 0);
         tracker.waitForID(0);
     } catch (Exception e) {}

     int iw = img.getWidth(this);
     int ih = img.getHeight(this);
     bi = new BufferedImage(iw, ih, BufferedImage.TYPE_INT_RGB);
     Graphics2D big = bi.createGraphics();
     big.drawImage(img,0,0,this);
     this.repaint();

   }
 }

which works fine, the two faked up maps are in the Jar at the
correct relative location to the package's directory, and all
is well.

The trace of the call shows that java.net.URL found my data
sets at:

Refreshed Map URL is:

jar:file:/home/rooty/java/EastValleyWaterForumInterface/evwfLocal.jar!/edu/asu/dt/evwf/images/EvwfSampleMap2.png
Refreshed Map URL is:

jar:file:/home/rooty/java/EastValleyWaterForumInterface/evwfLocal.jar!/edu/asu/dt/evwf/images/EvwfSampleMap1.png

The same code, running not from the jar file, found them here, in
normal, non-jar-archive relative file path names, converted to full
ones, instead:

Refreshed Map URL is:

file:/home/rooty/java/EastValleyWaterForumInterface/edu/asu/dt/evwf/images/EvwfSampleMap2.png
Refreshed Map URL is:

file:/home/rooty/java/EastValleyWaterForumInterface/edu/asu/dt/evwf/images/EvwfSampleMap1.png

But now, I want to _run from_ the jar, but _access files_ (the real
map data this time, being updated by an independent process from
outside my control) from a non-jar directory relative to the one in
which the jar file sits.

How do I convince java.net.URL (or more correctly the
EvwfUtilities.class.getResource( String dataRelativeLocation )
calls) to do that?

xanthian.