code: ExtensionLoader createDefaultExtensionLoader() {
          // First find the right Class/ClassLoader
          final Class<?> extensionLoaderImplClass;
          try {
              extensionLoaderImplClass = ClassLoaderSearchUtil.findClassFromClassLoaders(EXTENSION_LOADER_IMPL,
                  getClassLoaders());
          } catch (final ClassNotFoundException cnfe) {
              throw new IllegalStateException(
                  "Could not find extension loader impl class in any of the configured ClassLoaders", cnfe);
          }
  
          // Return
          return SecurityActions.newInstance(extensionLoaderImplClass, new Class<?>[] { Iterable.class },
              new Object[] { this.getClassLoaders() }, ExtensionLoader.class);
      }
docs: Obtains the default {@link ExtensionLoader} to be used if none is specified
  
  @return