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
/**
	 *	Open an appropriate destination browser so that the user can specify a source
	 *	to import from
	 */
	protected void handleDestinationBrowseButtonPressed() {
		FileDialog dialog= new FileDialog(getContainer().getShell(), SWT.SAVE);
		dialog.setFilterExtensions(new String[] {"*.jar", "*.zip"}); 
		String currentSourceString= getDestinationValue();
		int lastSeparatorIndex= currentSourceString.lastIndexOf(File.separator);
		if (lastSeparatorIndex != -1) {
			dialog.setFilterPath(currentSourceString.substring(0, lastSeparatorIndex));
			dialog.setFileName(currentSourceString.substring(lastSeparatorIndex + 1, currentSourceString.length()));
		}
		else
			dialog.setFileName(currentSourceString);
		String selectedFileName= dialog.open();
		if (selectedFileName != null)
			fDestinationNamesCombo.setText(selectedFileName);
	}
	/**
	 * Returns the resource for the specified path.
	 *
	 * @param path	the path for which the resource should be returned
	 * @return the resource specified by the path or <code>null</code>
	 */
	protected IResource findResource(IPath path) {
		IWorkspace workspace= ResourcesPlugin.getWorkspace();
		IStatus result= workspace.validatePath(
							path.toString(),
							IResource.ROOT | IResource.PROJECT | IResource.FOLDER | IResource.FILE);