Bug 31556 Export jar from Navigator view fails
(M5 build) In Navigator view (resource perspective), right-click on a src/ directory containing your sources, select export->jar file and the package selector opens with no resource selected (and finish button disabled); but it seems that the src/ dir is really selected, because if you re-select it in the window, it ends up with a "jar creation failed" and a lot of duplicate entries in the error log. If you try the same from the Projects view (Java browsing perspective), it works fine.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/jarpackager/JarPackageWizardPage.java
* accessor for subclasses.
	 *
	 * @return an iterator over the collection of elements currently selected for export
	 */
	protected Iterator getSelectedResourcesIterator() {
		return fInputGroup.getAllCheckedListItems();
	}
	/**
	 * Persists resource specification control setting that are to be restored
	 * in the next instance of this page. Subclasses wishing to persist
	 * settings for their controls should extend the hook method 
	 * <code>internalSaveWidgetValues</code>.
	 */
	public final void saveWidgetValues() {
		
		IDialogSettings settings= getDialogSettings();
		if (settings != null) {
			String[] directoryNames= settings.getArray(STORE_DESTINATION_NAMES);
			if (directoryNames == null)
				directoryNames= new String[0];
			directoryNames= addToHistory(directoryNames, getDestinationValue());
			settings.put(STORE_DESTINATION_NAMES, directoryNames);
			settings.put(STORE_EXPORT_CLASS_FILES, fJarPackage.areClassFilesExported());
			settings.put(STORE_EXPORT_JAVA_FILES, fJarPackage.areJavaFilesExported());
			
			settings.put(STORE_COMPRESS, fJarPackage.isCompressed());
			settings.put(STORE_OVERWRITE, fJarPackage.allowOverwrite());
		}
		
		internalSaveWidgetValues();