Bug 11317 Won't export some files to .jar.
Create a new java project called "Foo". In the file system, create a folder named "Foo scripts", and in this folder create a file named "foo.txt". Drag this folder into the eclipse packages view and add it to the "Foo" project. Now try to export the project "Foo" to a .jar file. Only the manifest file shows up, even if the file "foo.txt" is checked!
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/jarpackager/JarFileExportOperation.java
Iterator iter= fJarPackage.getSelectedElements().iterator();
		while (iter.hasNext()) {
			Object element= iter.next();
			IResource resource= null;
			if (element instanceof IJavaElement) {
				IJavaElement je= (IJavaElement)element;
				try {
					resource= je.getUnderlyingResource();
				} catch (JavaModelException ex) {
					addWarning(JarPackagerMessages.getFormattedString("JarFileExportOperation.underlyingResourceNotFound", je.getElementName()), ex); 
					return count;
				}
			}
			else
				resource= (IResource)element;
			if (resource.getType() == IResource.FILE)
				count++;
			else
				count += getTotalChildCount((IContainer)resource);
		}
		return count;
	}
	
	private int getTotalChildCount(IContainer container) {
		IResource[] members;
		try {
			members= container.members();
		} catch (CoreException ex) {
			return 0;
		}