private static synchronized String getJavascript() {
   if (jstext == null) {
     InputStream istr = null;
     try {
       ClassLoader loader = Thread.currentThread().getContextClassLoader();
       istr = loader.getResourceAsStream(JAVASCRIPT_RESOURCE);
       jstext = StringUtil.fromInputStream(istr);
       istr.close();
     } catch (Exception e) {
       log.error("Can't load javascript", e);
     } finally {
       IOUtil.safeClose(istr);
     }
   }
   return jstext;
 }
 private ExternalizableMap loadMap(String extMapName, ClassLoader loader)
     throws FileNotFoundException {
   String first = null;
   String next = extMapName;
   List<String> urls = new ArrayList<String>();
   ExternalizableMap res = null;
   while (next != null) {
     // convert the plugin class name to an xml file name
     String mapFile = next.replace('.', '/') + MAP_SUFFIX;
     URL url = loader.getResource(mapFile);
     if (url != null && urls.contains(url.toString())) {
       throw new PluginException.InvalidDefinition("Plugin inheritance loop: " + next);
     }
     // load into map
     ExternalizableMap oneMap = new ExternalizableMap();
     oneMap.loadMapFromResource(mapFile, loader);
     urls.add(url.toString());
     // apply overrides one plugin at a time in inheritance chain
     processOverrides(oneMap);
     if (res == null) {
       res = oneMap;
     } else {
       for (Map.Entry ent : oneMap.entrySet()) {
         String key = (String) ent.getKey();
         Object val = ent.getValue();
         if (!res.containsKey(key)) {
           res.setMapElement(key, val);
         }
       }
     }
     if (oneMap.containsKey(KEY_PLUGIN_PARENT)) {
       next = oneMap.getString(KEY_PLUGIN_PARENT);
     } else {
       next = null;
     }
   }
   loadedFromUrls = urls;
   return res;
 }