code: private void loadCategories() {
  
          CmsRpcAction<List<CmsCategoryTreeEntry>> action = new CmsRpcAction<List<CmsCategoryTreeEntry>>() {
  
              @Override
              public void execute() {
  
                  start(200, true);
                  CmsCoreProvider.getService().getCategoriesForSitePath(m_dialogBean.getReferenceSitePath(), this);
              }
  
              @Override
              protected void onResponse(List<CmsCategoryTreeEntry> result) {
  
                  m_dialogBean.setCategories(result);
                  m_handler.setCategoriesTabContent(result, new ArrayList<String>());
                  m_handler.onCategoriesTabSelection();
                  stop(false);
              }
          };
          action.execute();
      }
docs: Loading all available categories.<p>