code: public void updateSite(String siteRoot) {
  
          try {
              CmsObject cloneCms = OpenCms.initCmsObject(m_cms);
              if (siteRoot == null) {
                  siteRoot = "/system";
              }
              cloneCms.getRequestContext().setSiteRoot(siteRoot);
              m_cms = cloneCms;
          } catch (CmsException e1) {
              LOG.error(e1.getLocalizedMessage(), e1);
          }
          updateValidation();
      }
docs: Updates the site root.<p>
  
  @param siteRoot the site root