Program not behaving the same after making it a JAR

Question

Hello,
I'm developing a program using Eclipse and wanted to export a JAR file to test out. I was able to successfully make the JAR file and it does run, but not as expected. For example, I have the following code which opens up a JFileChooser and lets the user select multiple files to be stored in a JList (via a list model). When I run this from the IDE during development, it works as it should, allowing me to select multiple files from the JFileChooser and adds all of the files to the JList. However, when I run the JAR, it lets the user select multiple files but only adds ONE file to the list. Not only that, but it doesn't seem to be running my "loadComparePaper()" method after adding the item to the list model.
JFileChooser fileChooser = new JFileChooser();  // New JFileChooser
fileChooser.setMultiSelectionEnabled( true );     // Allow multiple files to be selected
FileFilter docFilter = new ExtensionFileFilter( null, acceptableFiles );  // "acceptableFiles" is an array of allowable extensions (not shown in this snippet)
fileChooser.addChoosableFileFilter( docFilter );  // Tell the JFileChooser to use my filter
int returnValue = fileChooser.showOpenDialog( null );  // Open the dialog; store result
if ( returnValue == JFileChooser.APPROVE_OPTION ) {
    File[] selectedFiles = fileChooser.getSelectedFiles();  // Get selected files; store in array
    for ( int i = 0; i < selectedFiles.length; i++ ) {  // For each selected file..
     compareListModel.addElement( selectedFiles[ i ].getName() );  // Add file name to list -- getting stuck here!
     loadComparePaper( selectedFiles[ i ] );  // Call method to load this file (read it)
}It seems like it's not running the whole for loop, because only one item is being added to the list and it never reaches "loadComparePaper()". Again, it works during development in the IDE and I've tried exporting the JAR quite a few times to see if that was the problem, but the JAR itself is executing.
Any ideas? I'm baffled as to why it works while I'm testing it out in the IDE, but after I export the JAR it's not working properly. Do you think this has something to do with Eclipse? Has anyone else experienced a problem like this?
Thanks

Answer 1

ThomYork:
Thank you for the advice. I'm new to using JARs and foolishly forgot or didn't realize that I should run it from the console to check for errors. Well, it seems this is the problem: I'm using Apache's POI package and have it stored in the directory +/my_project/lib/poi/+. Within the +/poi/+ folder are 3 JAR files that my program references. When I run my app from within the IDE, I don't get any errors because I've included them in the build path. However, when I run my JAR, it can't find the classes -- it doesn't seem to be looking in the +/lib/poi/+ folder even though my JAR file is in the same root directory as the main class when I run it within the IDE (i.e., both my_main_class and my_main_jar are in the same level directory, and would need to look in the +/lib/poi/+ folder for the other packages).
So I guess my problem is... my JAR file doesn't "see" the path of the other packages I'm using. In Eclipse, I've configured my project to include these other packages in the build path (and also the "Order and Export" build path) so I thought it would include them, but that doesn't seem to be working.
Am I missing something? How do I include JARs in other packages / folders so that they work in my JAR?
Thanks again
EDIT: I see some other people on this forum experiencing similar issues and I noticed you've helped them out. I tried creating a manifest file, but that didn't work, either... just to be more specific, this is the error message I'm getting:
Exception in thread "AWT-EventQueue-0" java.lang.NoClassDefFoundError: org/apache/poi/poifs/filesystem/POIFSFileSystem
        at OneToOne.loadSourcePaper(OneToOne.java:907)Edited by: ibanezplayer85 on Aug 14, 2008 10:19 PM