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
* @see #createFile
	 */
	protected IFile createFileHandle(IPath filePath) {
		if (filePath.isValidPath(filePath.toString()) && filePath.segmentCount() >= 2)
			return ResourcesPlugin.getWorkspace().getRoot().getFile(filePath);
		else
			return null;
	}
	/**
	 * Set the current input focus to self's destination entry field
 	 */
	protected void giveFocusToDestination() {
		fDestinationNamesCombo.setFocus();
	}
	/* 
	 * Overrides method from WizardExportResourcePage
	 */
	protected void setupBasedOnInitialSelections() {
		Iterator enum= fInitialSelection.iterator();
		while (enum.hasNext()) {
			Object selectedElement= enum.next();
			if (selectedElement instanceof ICompilationUnit || selectedElement instanceof IClassFile || selectedElement instanceof IFile)
				fInputGroup.initialCheckListItem(selectedElement);
			else
				fInputGroup.initialCheckTreeItem(selectedElement);
		}
		
		TreeItem[] items= fInputGroup.getTree().getItems();
		int i= 0;
		while (i < items.length && !items[i].getChecked())