Bug 67890 [PropertiesView] Exception when entries added to properties view
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/views/properties/ResourcePropertySource.java
*/
    public ResourcePropertySource(IResource res) {
        this.element = res;
    }
    /**
     * Return the value for the date String for the timestamp of the supplied resource.
     * @return String
     * @param IResource - the resource to query
     */
    private String getDateStringValue(IResource resource) {
        if (!resource.isLocal(IResource.DEPTH_ZERO))
            return NOT_LOCAL_TEXT;
        IPath location = resource.getLocation();
        if (location == null) {
            if (resource.isLinked())
                return UNDEFINED_PATH_VARIABLE;
            return FILE_NOT_FOUND;
        } else {
            File localFile = location.toFile();
            if (localFile.exists()) {
                DateFormat format = new SimpleDateFormat();
                return format.format(new Date(localFile.lastModified()));
            }
            return FILE_NOT_FOUND;
        }
    }
    /* (non-Javadoc)
     * Method declared on IPropertySource.
     */
    public Object getEditableValue() {