code: public void start()
     {
        if (!started)
        {
           try
           {
              NodeData jcrSystem = (NodeData)dataManager.getItemData(Constants.SYSTEM_UUID);
              if (jcrSystem != null)
              {
                 NodeData exoNamespaces =
                    (NodeData)dataManager.getItemData(jcrSystem, new QPathEntry(Constants.EXO_NAMESPACES, 1),
                       ItemType.NODE);
                 if (exoNamespaces == null)
                 {
                    initStorage(jcrSystem, !repConfig.getAccessControl().equals(AccessControlPolicy.DISABLE));
                    this.nsRoot =
                       (NodeData)dataManager.getItemData(jcrSystem, new QPathEntry(Constants.EXO_NAMESPACES, 1),
                          ItemType.NODE);
                 }
                 else
                 {
                    this.nsRoot = exoNamespaces;
                 }
              }
              else
              {
                 throw new RepositoryException("Nodetypes storage (/jcr:systemnode) is not initialized.");
  
              }
           }
           catch (RepositoryException e)
           {
              throw new RuntimeException(e.getLocalizedMessage(), e);
           }
  
           started = true;
        }
     }
docs: {@inheritDoc}