code: @Override
      public I_CmsReportThread initializeThread() throws CmsRuntimeException {
  
          if (getParamIndexes() == null) {
              CmsIllegalArgumentException ex = new CmsIllegalArgumentException(
                  Messages.get().container(Messages.ERR_SEARCHINDEX_EDIT_MISSING_PARAM_1, PARAM_INDEXES));
              LOG.warn(ex);
  
              try {
                  getToolManager().jspForwardTool(this, "/searchindex", null);
              } catch (Exception e) {
                  LOG.error(e);
              }
  
              throw ex;
          }
          List<String> indexes = extractIndexNames();
          CmsIndexingReportThread thread = new CmsIndexingReportThread(getCms(), indexes);
          return thread;
      }
docs: Returns the <b>unstarted</b> <code>Thread</code> that will do the work of rebuilding the indexes
  provided by the request parameter "indexes" value (comma-separated List).<p>
  
  @throws CmsRuntimeException if the request parameter "indexes" is missing.
  
  @return the <b>unstarted</b> <code>Thread</code> that will do the work of rebuilding the indexes
  provided by the request parameter "indexes" value (comma-separated List)
  
  @see org.opencms.workplace.list.A_CmsListReport#initializeThread()