code: private ExternalContentManager getExternalContentManager()
              throws Exception {
          if (s_ecm == null) {
              Server server;
              try {
                  server = Server.getInstance(new File(Constants.FEDORA_HOME),
                          false);
                  s_ecm = (ExternalContentManager) server
                          .getModule("org.fcrepo.server.storage.ExternalContentManager");
              } catch (InitializationException e) {
                  throw new Exception(
                          "Unable to get ExternalContentManager Module: "
                                  + e.getMessage(), e);
              }
          }
          return s_ecm;
      }
docs: Gets the external content manager which is used for the retrieval of
  content.
  
  @return an instance of <code>ExternalContentManager</code>
  @throws Exception is thrown in case the server is not able to find the module.