Error when no -Dconfluence.plugins.extra.bundled.locations is specified

    public List<PluginLoader> get()
    {
        List<PluginLoader> loaders = new ArrayList<PluginLoader>();

        for (String pluginModuleXmlLocation : pluginModuleXmlLocations)
        {
            loaders.add(new SinglePluginLoader(pluginModuleXmlLocation));
        }

        loaders.addAll(configuredLoaders);

        String[] extraBundledLocations = getExtraLocationsForSystemProperty(EXTRA_BUNDLED_PLUGINS_SYSTEM_PROPERTY);

        for (String extraBundledLocation : extraBundledLocations)
        {
            File location = new File(extraBundledLocation);
            if (!location.exists() || !location.canRead())
            {
                log.error("Unable to load extra plugins from " + extraBundledLocation + " specified in -D" + EXTRA_BUNDLED_PLUGINS_SYSTEM_PROPERTY + ". file not found or unreadable");
            }
            else
            {
                log.info("Loading additional plugins from " + extraBundledLocation);
                loaders.add(extraBundledPluginsFactory.newPluginLoader(location));
            }
        }

        return Lists.newArrayList(Collections2.filter(loaders, new Predicate<PluginLoader>() {
            @Override
            public boolean apply(@Nullable PluginLoader input)
            {
                return input != null;
            }
        }));
    }