docs: protected boolean refreshFromSystem() {
          Lock lock = this.namespacesLock.writeLock();
          try {
              lock.lock();
              // Re-read and re-register all of the namespaces ...
              SessionCache systemCache = repository.createSystemSession(context, false);
              SystemContent system = new SystemContent(systemCache);
              Collection<Namespace> namespaces = system.readAllNamespaces();
              if (namespaces.isEmpty()) return false;
              this.cache.clear();
              this.cache.register(namespaces);
          } catch (Throwable e) {
              logger.error(e, JcrI18n.errorRefreshingNodeTypes, repository.name());
          } finally {
              lock.unlock();
          }
          return true;
      }